[This book is reproduced from a photocopy in my collection. It originally was published in a pamphlet style in short columns which I could not maintain in this reproduction. It is most noticeable in the page numbering. I have tried to maintain the original grammar, spelling, and punctuation.
The effort of reproducing and reading this work is worthwhile as the many aspects of brewing haven’t changed much since 1883 to now; over 138 years later. I suggest that every reader notices the many references to the hours of mashing. It seems that two hours was the normal time allotted for that procedure and the bare minimal time used today is suspect and worthy of review. Much emphasis is given to the ratio of maltose to dextrin in producing a balanced wort.
The author, T.W. Lovibond became the Managing Director of Newcastle Breweries. He was only one of several Lovibond brothers involved in the brewing industry.]
BREWING WITH RAW GRAIN: A PRACTICAL TREATISE
THOS . WATSON LOVIBOND , F.C. S.
FIRST PRIZEMAN AND SILVER MEDALLIST IN HOUOURS GRADE IN BREWING, CITY AND GUILDS OF LONDON INSTITUTE TECHNOLOGICAL
EXAMINATIONS , 1882.
E. & F. N. SPON, 16, CHARING CROSS.
44, MURRAY STREET.
Page iii Preface Page 1 Diastase Page 9 Starch Page 14 Saccharification in a Separate Vessel Page 27 Saccharification in the Mash-Tun Page 37 Saccharification Under Pressure Page 42 Solution of Starch by Heat Page 45 Unprepared Grain in the Mash Page 52 Conversion by Acid Page 55 Comparison of Materials Page 66 Invert Sugar and Saccharum Page 70 English Infusion Process (Professor Graham’s Tables of Experiments) Page 75 Table of Experiments by the Author on Rice Flour
The greater part of the following pages was written at the request of the Editor of the “Brewers’ Guardian” and appeared in that journal dụring the months of October, November, and December last. When they were begun the hop crop was still in the uncertain future, and brewers were unaware of the need that would soon arise for using every possible means to compensate, as possible, for the extra cost of hops. Thus “Brewing with Raw Grain” has become a subject of rather than less interest to the brewing trade, and I therefore induced to seek a wider and more permanent circle of readers than can be afforded by any journal, however prominent.
In republishing the articles in the present form I have taken the opportunity of adding to the subject matter and also of printing some analytical tables which are of interest in connection with raw grain. That portion of the tables which has been compiled by Professor Graham is taken, with his kind permission, from his paper on Lager Beer.
I have endeavoured to treat the subject in a practical way, and, whilst pointing out the principles upon which the brewer must act, to indicate the cheapest and simplest method of applying those principles. The adaptability of the mash-tun to the purposes of a saccharifying vessel has been comparatively overlooked until recently; the practicability of using barley, and even rice, without preparation of any kind beyond grinding, and in the case of barley, kiln-drying, has also been but little known.
I hope I have succeeded in showing that raw grain can be easily, cheaply and beneficially used in partial substitution for malt. The chemical substances produced by its use, though differing in proportions, are identical in kind with those obtained from malt. It is, therefore, in proper proportions, a real substitute for malt, and one the use of which will not give rise in the minds of consumers to the feeling caused by the mysterious and sometimes nauseous compounds which as so-called substitutes for hops are largely advertised.
If any of my readers desire to enquire further on the subject, or if there are any points not yet clear to them, I shall be glad to do what I can to explain on hearing from them.
Opinions among brewers may differ as to the value of many of the restriction imposed on the trade by the operation of the new method of charging a brewing duty in place of the old malt duty. But all must agree that the liberty given at the same time to use any material capable of yielding a saccharine extract is any unmixed benefit. Yet it is somewhat remarkable that the brewing trade generally has up to the present time taken advantage to a very small extent of the long desired privilege. Malt, and one or other of the numerous sugars, invert sugars, saccharums and glucoses so largely advertised, are the only materials employed in the majority of breweries; while raw grain, by far the cheapest substitute for malt, and, under proper management and in proper proportions, a perfect one, is comparatively neglected. Here and there attempts, in most cases resulting in failure, have been made to use raw grain, but very few brewers have been so far successful in their experiments as to adopt its systematic use in any but the smallest proportions. It is proposed in the following pages to point out some of the reasons of the numerous failures; to explain in a practical rather than a scientific way the conditions under which raw grain may be employed for brewing purposes with safety and success; and to compare the values of the various descriptions of grain available, alike from the counting-house and the mash-tun points of view.
Before proceeding to examine the various methods in which raw grain may be used, and the apparatus required for the purpose, it is necessary to describe the substances, so far as they concern the brewer, which make up the grain, and the conditions theoretically required for their conversion into the form in which they are capable of assisting in fermentation. But as these pages are intended essentially for the practical brewer, this description will be as free as possible from scientific technicalities, and will go only so far as is necessary to make the problem clear to the unscientific mind.
Barley, rice, maize, wheat, oats, and rye are the only materials which will be treated of, as they alone, so far as this country is concerned, and at the same time cheap enough and good enough for the brewer’s purpose. Sago starch is a very pure material, of very high percentage value, but its price is practically prohibitory; and though it would be interesting to know how sago would behave in the mash-tun, as a prepared starch and not a “raw grain,” it is scarcely within the scope of the present inquiry.
The above mentioned cereals contain various substances, classed together as nitrogenous or albuminoids substances, which form from about 5 to 15 per cent of the total of the grain. Comparatively little is known of these albuminoids substances and their properties, but some of them are soluble in cold water only; others in hot; some at all temperatures, and some at none. In brewing, the most insoluble of them remain in the mash-tun, and are an important factor in producing the feeding value of the grains. The remainder find their way into the copper, where, under the influence of boiling and the tannin of the hops, a great part of them is precipitated in the flocculent form so familiar to the brewer when he sees his worts “break.” Still more are deposited by cooling on the coolers and refrigerators, so that the quantity remaining dissolved in the wort after this triple separation, does not amount to more than from 1.75 to 4 per cent of the original malt, the total quantity of nitrogenous matter in malt being from 9 to 12, or even 13 per cent. Thee soluble albuminoids are necessary for the proper nourishment of the yeast; but comparatively little suffices for this purpose. What is not removed by the yeast remains in the beer, and, while it plays an important part in producing flavor and fullness, an excessive quantity of it has a very damaging influence on the condition and keeping property of the beer. Malt which contains more than 2.5 per cent of soluble albuminoids is scarcely fit for export brewing, and malt with more than 3 percent is a dangerous material for any but running beers. A knowledge of this will enable the brewer, who is compelled to use malt containing too high a percentage of soluble albuminoids, to select for his use such raw grain and other materials as are calculated to restore the proportion he desires in his beer.
Among the soluble albuminoids of malt is found the substance called diastase, which plays so important a part in the mash-tun. Its function is, by its action on starch in the presence of heat and water, to convert the starch into first, dextrine, and then by degrees into maltose. The conversion into dextrine takes place very rapidly, but the complete conversion of the whole of the dextrine into maltose is only effected after many hours mashing – not less than seven of eight. The progress of this conversion can be very easily watched experimentally by adding a small quantity of ground malt to so some warm boiled starch. Before the malt is added, the solution will give the intensely blue reaction with iodine which is characteristic of starch. The instant the mash is stirred in the reaction becomes purple, owing to the production of some of the earlier or erythro-dextrines. These have a brown reaction with iodine, and the mixture of the brown and blue produce the purple. As the conversion proceeds the starch disappears, and the iodine reaction becomes quite brown; in a few minutes and brown reaction disappears, showing that the erythro-dextrines have in their turn converted into achroo-dextrine and maltose, neither of which has any reaction with iodine.
Diastase is present, more or less, in all malted grain; but in malt made from barley it exists in a much larger degree than in any other. Thus it is that barley malt is so pre-eminently suited for the use of brewers. There is no ready way determining of the amount of diastase in malt; the only practicable method of judging of the diastatic power of a given sample is to determine the proportion of maltose to dextrine present in the wort by means of Fehling’s copper solution. The higher the proportion of maltose to dextrine obtained under the same conditions as to time of mashing, heat, and quantity of water used, the farther the conversion has proceeded, and consequently the greater is the diastatic activity of the malt. This determination, however, takes some hours to arrive at, and requires some technical knowledge before it can be undertaken
Diastase is able to effect the conversion of many times as much starch as it finds in the malt of which it forms a part, and it is this excess of power which the brewer employs in making use of raw grain. Distillers are able to make a mash of malt and raw grain, in which only one tenth of the whole is malt; but the brewer, who has to produce an article which is bright, good in flavor, and which will keep sound, is obliged to be much more cautious in his mode of procedure than the distiller, who turns his wash into the still immediately after fermentation.
The action of the diastase on starch solution is not by any means uniform in its operation. It depends primarily on temperature. In the cold it has little or no action; at about 120 oF it begins to operate more actively, and the temperature of greatest activity is from 145 to 150 oF. Above these temperatures diastase gradually weakens in power, until at about 180 oF it becomes practically inert; boiling destroys it power entirely.
The presence of water is necessary for the action of diastase, and the more water present the better the conversion, so that the proportion of maltose to dexrine is always higher after a thin mash than in a stiff one, other conditions being the same. Time, also, of course, has an important influence on the diastatic action. Conversion is very rapid during the first hour; it then becomes slower and slower, until, in the case of well-grown, well-cured, active malt, at the end of seven or eight hours’ mash, maltose alone, or with but very little dextrine, is present.
From these observations it will be seen that the saccharine portion of wort from the mash-tun is always a mixture of maltose and dextrine, in proportions varying according to the temperature and time of mashing, the quantity of water used, and, most of all, to the natural diastatic activity of the malt. It also follows that in any attempt to compare the diastatic power of different malts, the conditions as to time, temperature, and quantity of water must always be the same. Professor Graham has made a very interesting series of experiments illustrating the influence of heat, time, and water on the action of diastase. By his kind permission the results, reprinted from his paper on Lager Beer, are given at the end of this volume.
The percentage of soluble albuminoids present in malt can be determined without any difficulty, and with but little previous practice, by the Wanklyn process; but useful as the result is, it is no guide to the diastatic power of the malt. The highest percentage of soluble albuminoids is found in badly-cured malts made from coarse, ill-harvested barleys, grown on heavy lands, whilst the greatest diastatic activity is found in malts well-grown on the malthouse floor, thoroughly kiln-dried, and made from mellow, well-harvested barley, grown on light lands.
Barley, rice, maize, wheat, oats and rye also contain, in proportions varying from about 50 to 80 per cent, a substance called starch, and it is this alone which supplies the saccharine material required for the subsequent process of fermentation. The starch is contained in exceedingly minute microscopic sacs or cells, each cell consisting of a thin skin or envelope, with its internal contents. The skin is composed of cellulose, and being insoluble, is of no interest to the brewer, except in so far as it adds very slightly to the bulk of his grains, and by its very bad power of filtration obstructs the freedom of his drainage. The internal contents of these cells form the substance known as starch, which it is the brewer’s aim to extract as completely as possible from the skins or cells containing it, and to convert, by means of diastase, into the more or less fermentable substances, maltose and dextrine.
In the presence of water, and under the influence of boiling heat or a little less, these starch cells burst, or exfoliate, as it is called, and the within-contained starch is dissolved in the water as starch paste or solution, which is very thick even when hot, and stiffens to a jelly on cooling. Theoretically, this is the most perfect method of extracting the starch from the containing cells, and in the laboratory, where small quantities are used, it is an easy and satisfactory way of preparing the starch for its quantitative determination. In the brewery, the mechanical difficulties in the way of manipulating a large quantity of the thick paste or jelly, and the persistent manner in which the starch thickens on the bottom and sides of the vessel, and if fire heat be used, becomes burnt, make the method scarcely practicable. As far as the writer knows, there is only one plan in operation in breweries in which starch is exfoliated by heat alone, and of this details will be given later on. It may be mentioned here that in dissolving starch by heat alone it is not sufficient to carry on the process until the solution appears jelly-like, as the solution of a very small proportion of the starch will make the whole mass stiff and pasty. Unless the dry starch is previously very finely ground indeed, the process of bursting the cells takes some little time, and, in fact, is not complete until the water and heat have penetrated to the very centre of each individual fragment of the material. Every housekeeper knows that in the case of rice for the table, it requires at least twenty minutes’ hard boiling in plenty of water to make each grain soft to the centre, in other words, to burst every cell. Consequently, the stewing of the ground grain must be continued for a time varying in proportion with the coarseness of the grinding.
Another method of forcing the starch cells to give up their contents, is to employ the osmotic or diffusion action of diastase.
To accomplish this, the ground grain is mixed with malt and water, and allowed to stand at as near 150 oF as possible, when the diastase of the malt finds its way through the cell walls and converts the within-contained starch into a solution of maltose and dextrine, which, being very fluid, readily escapes from the cells, and can be separated by filtration and washing. This operation, it will at once be seen, is not a quick one, like boiling or stewing. In most cases it is also an incomplete one. Barley and rye give upon the whole of their starch under the influence of diastase alone within the limits of time occupied by an ordinary mash, but most other descriptions of grain require considerable heat to bring them into the condition necessary for complete conversion. In the latter cases the proportion of starch converted or extracted by diastase unaided varies to some extent in proportion with the size and hardness or stubbornness of the starch cell, a small-celled, hard starch manifestly yielding up its contents with less readiness than a large, soft celled one. The use of raw grain whether in the form of “gelatinized grain,” of “brewing meal,” or of ground grain simply, direct in the mash-tun, without any preparatory heating process, depends for the measure of its success on this osmotic action.
An apt illustration of osmotic action is found in the growth of barley on the malthouse floor. Just as the acrospires advances up the side of the corn, so does its influence extend through the substance of the corn, from starch cell to starch cell, malting the grain as it goes. An insufficiently grown corn will be found flinty or starchy at the ungrown end, while a three-quarters or fully grown one is malt throughout.
The difficulties attending both the above mentioned methods of dissolving starch have led brewers almost universally to adopt a combination of the two. The essence of nearly all the plans at present in use is the following general plan: – The grain is mixed with a suitable quantity of water, a greater or less proportion of diastase is added, either in the form of unboiled wort, of cold infusion of malt, or of ground malt itself; the temperature is gradually raised from 105 oF or less, to a point somewhat short of boiling, the mixture being thoroughly stirred the whole time to prevent settling: it is then cooled to mashing heat, mixed with the malt in the mash-tun, and allowed to stand in the usual way. By these means the starch cells are subjected to the osmotic or diffusion action of diastase for a short time at the temperature most suitable for diastatic action – say 145 to 150 oF. A very short duration of this diastatic influence prepares and softens the starch for the ensuing exfoliation by heat, so that although very little actual conversion takes place, the starch on being heated does not gelatinize, and requires comparatively little stewing, and not very high heat: 185 oF in most cases is sufficient. At this stage the solution takes the form of a fairly thin gruel, and, on being cooled to mashing heat, can be readily run through pipes to the mash-tun.
The above preliminary explanation may seem somewhat tedious to those who have already studied the subject, but as these pages are intended more particularly for those to whom the use of raw grain is quite new, or who have failed to use it successfully, it has been thought necessary to go somewhat into detail
SACCHARIFICATION IN A SEPARATE VESSEL
In the following examination of the various methods by which the starch of raw grain may be converted into the maltose and dextrine required for fermentation, the ordinary measures familiar to brewers will always be made use of. By a quarter of malt or grain will be understood the Excise standard of 336 lbs. weight, or 8 bushels of 42 lbs. each. Proportions of water will be spolken of in barrels per quarter of malt or grain, as the case may be. Extract will be given in pounds per quarter, which are convertible into degrees of gravity by multiplying by the factor 2.777. The Fahrenheit scale will be used for denoting temperature. In comparing the cost of different materials, the results will be given as the cost per pound of extract expressed in pence and decimals of penny; thus malt costing 42s . 6d and yielding 85 lbs. per quarter, gives sixpence as the cost of a single pound of extract. If it is desired to express extract in the form of percentage of soluble solids, it can be done by dividing the extract in pounds per standard quarter by the factor 1.26; e.g. malt yielding 85 lbs. per quarter has 67.5 per cent of soluble solids. Professor Graham, in his most useful leaflet, entitled “Data for Brewers,” gives 1.2 as the factor for this purpose, but his calculation was made before the abolition of the malt duty, and when the imperial quarter, with an average weight of 40 lbs. per bushel, was in use. Now that the bushel weighs 42 lbs., the factor becomes 1.26 and this applies equally to malt and grain.
The first mode of conversion which claims our attention is what may be called the ordinary method, which has been referred to in the previous article as combining both the diastatic and the heating methods of attacking the starch cells. With very slight variations in detail only, and not in principle, this is the method recommended by most of the vendors of raw grain, and, with proper management, it is efficient.
The only plant required which is not to be found in most breweries is a saccharifier, or stewing vessel, with powerful internal rouser, and means of rapidly heating nearly or quite to boiling point. There are many forms of apparatus which have been devised by engineers for this purpose, some of them sufficiently complicated and costly to be highly satisfactory to the manufacturer of the machine. But in this, as in many matters, the simplest and cheapest form of machine is as good as any. An iron or well made wooden vessel, round in shape to ensure freedom from unmixed corners, with a propeller shaped rouser near the bottom, fixed on a perpendicular central shaft driven by steam-power, or even by hand in very small breweries, and having he means of introducing naked steam, is all that is required, and will cost less than most of the contrivances advertised. The steam should be admitted through on or more pipes having a large number of tiny holes opening downwards instead of simply an open end. The heating will be more uniform, and there will be less noise than if an open pipe only is used. The steam-cock should be as close as possible to the vessel, and the length of pipe inside the vessel should be easily detachable, so that it can be taken off and cleaned daily. If this is not done the grain, which will find its way into the pipe as soon as the steam is shut off, will stop up the small holes, as well as become putrid and a source of danger. Care should be taken to ensure clean steam, but where no objectionable boiler composition is used, and where there is sufficient distance, say 20 feet per pendicularly, between the boiler and the vessel, no harm need be feared.
The vessel must be fixed at such a height as to command the mash-tun, and be commanded by the hot and cold liquor supplies. The hot liquor supply can, if necessary, be dispensed with, and the steam alone used; but it will save time and labour, as well as be more convenient for cleaning purposes, if hot liquor is laid on.
The vessel should also be furnished with a hopper over, sufficiently large to contain the grain for one brewing. The pipe leading from the saccharifier to the masher or mash-tun should be of ample size to prevent possible choking not less than two inches in diameter, and the tap used should have a clear straight passage-way, so as to offer as little obstruction as possible. This tap should, like the steam-cock, be fixed close to the vessel. To prevent any of the grain, which sinks at the early stage of the process, from getting into the outlet pipe, it is advisable to use a wooden plug inside in addition to the tap. This plug should be long enough to reach to the top of the vessel, so that it can easily removed when he vessel is full.
Where an outside mashing machine is used it is best to run the grain mixture, after preparation, into the masher with the liquor supply; but where internal rakes only exist, the mixture can be run direct into the mash-tun over some kind of spreader, so as to distribute it as widely as possible. A piece of board will do for the purpose, a sparger will not.
The size of the saccharifier should be at the very least 5 barrels for every quarter of grain which is to be used in it; that is to say, a vessel for 10 quarters of grain should be of a capacity of not less than 50 barrels, and so on. In one brewery where this plan is employed with notable success, 9 barrels of liquor are used to each quarter of meal, requiring a vessel twice as large as that just described. This may seem more than is necessary, but 5 barrels per quarter is the very least that ought to be used, and the brewer erecting a new vessel is recommended to allow room for 7 barrels. Special attention must be given to this point, as the completeness of the conversion in the mash-tun, and the openness of the drainage, depend upon the thoroughness of the preliminary preparation, and that, in its turn, depends upon the mixture being sufficiently dilute. A little extra size in the saccharifier will be much less inconvenient than the contrary.
The only other apparatus necessary is an efficient internal mashing machine with rakes, but this is so commonly found in breweries that it can scarcely be considered as part of the plant required solely for the use of raw grain. It is, however, an absolute necessity for good work; it is impossible to get a perfect admixture of the grain and malt without a good internal machine. Very slight irregularities in mixing will cause great unevenness in drainage, and as the loss of extract arising from uneven drainage is much more serious with a mixed mash of malt and grain than with malt alone the greatest care must be taken to ensure an uniform mash. This cannot be urged too strongly. Bad drainage of the mash is the greatest practical difficulty in using raw grain, and is the cause of nearly all of the numerous failures.
The vessel being in good order, the first step in the process of saccharification is to run in not less than 3, or still better 4 barrels of liquor per quarter at about 160 o. Then, having started the rouser vigorously, run in the grain by degrees, as such a speed that it is thoroughly wetted as it goes in. If it is not run too quickly there is some times a tendency to ball, especially is he grain be finely ground of the heat too high. The temperature of the mixture should not be more than 130 o. The exact heat of the liquor required to get this result will vary somewhat, according to the size of the vessel, the time of year, and the condition of the grain, but a single train with liquor at 160 o will be sufficiently near the mark to enable the brewer to hit 130 o very closely in the ensuing brewings. The reasons for aiming at so low a heat as 130 o at this stage are, firstly, that diastase is more soluble at this temperature than a higher one; and, secondly, that if grain is mixed at once with very hot liquor, the fragments are, to some extent, glazed or covered with a coating of coagulated starch and albuminoids substances, which retards the action of the diastase about to be added. A good cook unconsciously applies this theory when, n boiling rice for curry she plunges it directly into an excess of boiling water for the purpose of keeping each grain of rice distinct and separate.
The rouser being kept constantly at work, finely ground malt should now be added, in the proportion of 5 per cent, the speed of the rouser may be slackened, so as only to keep the whole bulk in constant but not violent circulation. Practice varies very much in this matter of the proportion of malt, some brewers using as little as 2 ½ and others as much as 10 per cent, but 5 per cent will be found quite sufficient. The malt once in and incorporated with the grain, the steam should be turned on and the heat raised steadily at the rate of 1 o, or not more than 1 ½ o, per minute to 185 o, at which point it should be allowed to remain for half or three quarters of an hour, until in fact no hardness is felt in rubbing the grist between the finger and thumb, and the grain is thoroughly cooked. The rouser should be kept going gently the whole time. The heat may then be raised quickly to 200 o or 205 o, when the steam should be shut off, the speed of the rouser increased, and enough cold liquor run in to reduce the temperature of the whole to mashing liquor heat. This will require about 1 ½ barrels per quarter, bringing up the whole bulk to about 5, or if 4 barrels of liquor be used in the first instance, to a little over 6 barrels per quarter of grain. At this stage the mixture will be in the form of a thin, smooth gruel, perfectly free from hard or uncooked bits of grain, and it is now quite fit for mashing with. The diastase of the malt has quite prevented the gelatinizing or thickening, which would have taken place had heat alone been used.
If it is desired to increase the diastatic action of the malt, the rise in heat can be arrested at 150 o, and continued as before, after 15 to 30 minutes’ rest at that point; but this will not be found necessary.
Instead of 205 o as the highest heat reached, some brewers boil for 5 or 10 minutes, but this requires a powerful coil or steam-jacket, and cannot be done with naked steam at ordinary pressures. Moreover, the disintegrating action of boiling on the walls of the starch cells is such that the drainage in the mash-tun impeded, particularly if the grain be at all finely ground.
The first step in the mashing process is to run into the mash-tun sufficient liquor at the usual mashing heat to fairly cover the false bottom; this should not be omitted, as it is of the utmost importance to prevent the grain, and to a less extent the malt, from settling into the holes or under the plates. About 8 or 10 inches of malt should then be run in, through the outside masher if there be one, with about 24 barrels of liquor per quarter, so as to form a stratum of malt alone at the bottom of the tun, and still farther keep the raw grain off the plates. The mixture of grain which has been so carefully prepared should now be turned on into the outside masher, to meet the malt, and the ordinary mashing liquor supply slackened, or even shut off, so that the outflowing malt and grain may have a consistency equivalent to about 21 barrels of liquor per quarter. The appearance will tell the brewer sufficiently nearly how to proportion the malt and liquor supplies so as to obtain this consistency. Care should be taken to run down the grain mixture fast enough to ensure its all being down before the malt, but there will be no difficulty in doing this if the mashing liquor is almost or quite replaced by the grain solution so long as the latter lasts. Any small quantity of malt remaining must of course be mashed with liquor alone, as at the beginning.
During the whole of this process the rakes must be kept moving briskly, and a gentle flow of liquor at mashing heat kept running under the plates; half a barrel per quarter, or at most three quarters, should suffice to keep a constant upward current on to or under the plates. This undercharge should be continued for two or three minutes after the mash is all in and the rakes stopped.
Assuming that 25 per cent of grain is being used in a 30 – quarter brewing, the following statement will show about the quantity of liquor that should have been employed, and the manner in which it will have been disposed : –
7 ½ qrs. grain and ½ qr. malt, saccharified and cooked with 5 barrels of liquor per quarter of grain 40 barrels 4 qrs. malt, mashed with 2 ¼ barrels liqour, per qr. 9 barrels 18 qrs. malt, mashed with prepared grain solution, and a little liquor in addition say 11 barrels Undercharge, ½ bbl. per qr. on the whole quantity 15 barrels Total liquor used 75 barrels
This quantity divided by 30 gives exactly 2 ½ barrels of liquor per quarter. This may seem to some too thin a mash, but it has been pointed out before that for good conversion and drainage raw grain requires more liquor than malt alone, and a stiffer mash than this would not give equally good results. As he extract from raw grain should be considerably higher than from malt, nearly the usual quantity of sparge liquor can still be run over the goods. A moderate proportion of saccharum, or still better, good invert sugar, can also be used to increase the quantity of sparge liquor required; farther reference will be made to this later on.
Nothing has been said about the required heat of the mashing liquor. The reason is, that the temperature of the liquor necessary to produce a given initial heat of the mash varies so much in different breweries that no fixed instructions can possibly be given on this point. If, however, the grain solution and mashing liquor are both brought to the heat which is known to be necessary to obtain the desired initial heat with malt alone, using 2 ½ barrels per quarter, the result will be almost inappreciably in excess of an all-malt mash. On the subject of initial heat or heat of the mash, the brewer requires no instruction, as the temperature which is found to give good results with malt alone, will, with malt and raw grain manipulated in this manner just described, produce a wort differing very little in composition from the malt wort.
In breweries where there is a steam copper fixed high enough to command eh mash-tun, it may very conveniently be employed as a saccharifying vessel. For a few experimental brewing, the necessary rousing can be done by hand, but it is advisable to fix an efficient mechanical rouser as soon as possible.
With due regard to the directions and precautions given, raw grain may be used for the first time without any fear of the goods draining badly. The worts will run quite bright, be of good flavor, and quite free from that soluble starch of which so many brewers have a morbid terror. This method is suitable for any grain ground to any reasonable degree of fineness, but the extra conversion gained by very fine grinding will be more than counterbalanced by the damaging effect on the drainage. The best results will be got from grain ground to the size of fine gunpowder; this subject will e referred to again when comparing different forms of grain.
SACCHARIFICATION IN THE MASH-TUN
The second method of using raw grain which claims attention is similar, in many respects, to that just described. The agency of both diastase and heat is employed, but there is the important difference between the two plans that no outside vessel or saccharifier is required for that about to be considered. The principles involved in the two methods are exactly the same, but in that now under consideration the mash-tun is made, by a very small and inexpensive addition, to do double duty, first as a saccharifier and then as a mash-tun proper. The credit of practically applying this very happy idea is claimed by Mr. A. H. Mure, of Hampstead, and this gentleman has recently published an account of the process he has devised.
Mr. Mure recommends that the steam should be introduced into the mash-tun below the false bottom, by means of 1 in. or 1 ¼ in. pipes, having about twice as many steam inlets as wort outlets, and suggests that the wort outflow pipes may be utilized as steam pipes if necessary. He also points out that it is advisable to fasten down he plates of the false bottom to prevent their being moved by the incoming steam. But it will probably be found more convenient to have a separate service for the supply of steam; and, if the suggestion made in chapter 3, to admit the steam through small holes opening down wards, be adopted, it will not be found necessary to fasten down the plates.
For the purpose of mashing, Mr. Mure divides the grist into three portions, the first being the malt used for preparing the grain, the second the grain itself, and the third the malt used in the mashing process proper in order to convert the first and second parts into the maltose and dextrine for fermentation. The proportions he prefers are: for the first portion of malt, 5-12ths of the total grist; for the raw grain, 3-12ths or 25 per cent; and for the remaining 4-12ths the second portion of malt. If more or less than 25 per cent of grain be used, the first lot of malt must be diminished or increased accordingly; one third of the whole grist should be kept back in malt alone for the final mash. The grain and the first portion of malt are to be thoroughly mixed before mashing. This can best be done by means of a separate hopper with a regulating slide, delivering the ground grain under the malt rolls in a sheet the same width as the rolls, but of course any good way of accomplishing the mixture will do.
Having covered the false bottom with liquor, the next step is to mash through an outside masher this mixed malt and grain with two barrels of liquor per quarter, the rakes moving sharply; and at the same time to undercharge half a barrel of liquor per quarter, at such a rate as to ensure its passing up through the plates slowly the whole time. The heat of the liquor for the outside masher, Mr. Mure says, should be about 160 o, which alone would produce an initial or mixture heat of from 140 o to 142 o. The heat of the undercharge should be about 200 o, so as to raise the actual heat of this first mash, when all is in, to about 150 o or 152 o. As soon as this mash is completed the steam is to be turned on, and the heat raised at a rate of not less than 1 ½ o nor more than 2 o per minute to 197 o. When this temperature is reached, the steam should be nearly or quite shut off, and he mash kept between 196 o and 200 o for 30 minutes, the steam being turned on a little from time to time, to counteract the loss of hear arising from radiation and the movement of the rakes.
After this half-hour’s stew, the steam is to be quite shut off, and an undercharge of cold liquor run in, sufficient to reduce the temperature of the mash to about 158 o, or such a point as will give an initial hear of 150 o to 152 o, after adding dry and thoroughly mixing in the remaining third of the total grist, consisting of malt alone. The quantity of cold liquor required for this cooling down will be about half that used for mashing the malt and grain in the first instance.
After the dry malt has been thoroughly mixed in, the rakes, which have been kept moving briskly the whole time, should be revolved slowly for 30 minutes, they stopped, and the goods allowed to stand for another 30 minutes. The taps should then be set, and about 14 barrels per quarter run off. An under charge of half a barrel to the quarter at 168 o is then run in, the rakes are set going again for a short time, the goods permitted to stand for 10 minutes, and the taps set again, sparging and finishing the running of the worts in the usual way.
The liquor used in a 30 – quarter brewing by this method is as follows:
5/12ths of the total grist in malt = 12 ½ qrs. and 3/12ths of the total
grist in grain = 7 ½ qrs. mashed with 2 barrels per quarter 40 barrels
Undercharge ½ barrel per quarter 10 barrels
to cool down 25 barrels
4/12ths of the total grist in malt = 10 qrs. mashed in dry Undercharge ½ barrel per quarter after setting tap 15 barrels
Total liquor used 90 barrels
3 barrels per quarter
These are the details of the plan preferred by Mr. Mure, but it will be evident that they can be varied in many ways to suit the exigencies of different breweries, or the views of different brewers. For instance, where there is no outside mashing machine, the grain and the first portion of malt previously mixed can be run in dry and mashed by means of the rakes only. Or where there are no facilities for mixing the malt and grain before mashing, they can be run into the mash-tun separately, for the malt and then the grain, the rakes being relied upon to thoroughly mix them.
It will be noticed that the total quantity of liquor, 3 barrels per quarter, used by Mr. Mure is large. The second mash and accompanying undercharge of half a barrel per quarter can be omitted with advantage, and the total quantity thus reduced to 2 ½ barrels per quarter, the same as in the method first described. With so large a quantity of mashing liquor as 3 barrels per quarter, it would be very difficult to run on enough sparging liquor to exhaust the goods without either using a very large quantity of invert sugar or saccharum, or adopting the unwise practice of making return worts.
The advantages of this method are : – Firstly, the absence of any extra plant, and this is undoubtedly a great benefit. Secondly, that the time taken in the process is not much longer than in mashing with malt alone. In an all malt mash the time occupied in mashing and standing is usually two hours or thereabouts; by this method it is three hours, or, including the second mash and undercharge, three hours and a half; whilst by the plan first described, in which a separate saccharifying vessel is used, the whole time taken, from beginning to setting tap, is not less than four hours, and most likely more. Thirdly, that the unmalted starchy portions of steely malts are, so far as the first 5/12ths of the grist are concerned, subjected to the same treatment as the raw grain, and a slightly increased extract is therefore obtained from such malts. The corollary of this is that where a brewer uses badly – grown malt, which he should not do at all if it can possibly be avoided, he should do so only in this first stage of the mash, reserving good, well – grown, and thoroughly kiln – dried malt of high diastatic power for the final stage. Fourthly, that the proportion of dexrine in the wort is much higher than with malt alone, or even than with malt and grain mashed with a separate saccharifier, using only a small percentage of malt in preparing the grain.
This question of the proportion of maltose to dextrine, however, is very much in the brewer’s own hands. When the raw rain is prepared by the method first described, with very little malt and ample stewing, the wort will be found to contain maltose and dextrine in very nearly the same ratio as with malt alone mashed in the usual way. But where, as in this second method, the diastase of more than half the total malt used is destroyed by heating, and the diastase in the remaining small portion of malt is required to do all the work, it is evident that the conversion cannot be carried so far, and consequently the ratio of maltose to dextrine is reduced. Between these two extremes the brewer can choose the point he finds to answer his purpose best. For running beers, where fullness of flavor is one of the first considerations, the large proportion of dextrine produced by this second method is an advantage. For stock beers, where keeping qualities are of most importance, the conversion should be more completely effected by using less malt in the first stage of the mash and more in the second. The proportions of malt mentioned as employed in the two stages of mashing are those preferred by Mr. Mure, but the quantity used in the first stage can be reduced to as little as 5 per cent on the raw grain without interfering with the success of the mash. In the writer’s opinion it should be reduced considerably in all cases, but more particularly when brewing stock beers. When diminishing the quantity of malt in the first stage of the mash, it is not at all necessary to use a separate saccharifying vessel; the second, or mash-tun method is equally applicable whether the first portion of malt be 5, or, as Mr. Mure recommends, nearly 200 per cent on the grain.
It may be mentioned that there is no necessity for the undercharge of half a barrel per quarter, which is run in during the first stage of mashing, to be of a higher heat than the liquor used in the outside masher. In many breweries there is only one hot liquor back, and consequently there are no means of using mashing liquor of two heats simultaneously. Where this is the case, the same liquor can be used for both masher and undercharge, the temperature being raised correspondingly.
In breweries where steam cannot be obtained quite clean, or where an objection is entertained to using naked team at all, the necessary heating power can be procured at comparatively small cost by means of a coil placed underneath the false bottom for this method, or, for the first plan, fixed in the saccharifying vessel.
Revolving mashing machines are constructed to contain heating appliances within themselves. Some, like Tizard’s attemperating masher of many years ago, have hollow arms to carry the steam, connected with a self-acting condensed water trap. A mashing machine having this object in view has recently been patented by Mr. Cave. Besides the usual solid rakes, it consists of two large copper steam chambers, somewhat like ploughshares, fixed radially on the central shaft of the machine, and revolving with the rakes very close to the false bottom, but without touching it. By regulating the supply of steam the heat of the mash can be very exactly controlled. These machines are all of them somewhat costly; and as naked steam or a steam coil will be found quite sufficient for the purpose required, it is not advisable to condemn a good mashing machine for the sake of putting in one of them. In erecting a new mash-tun they offer advantages worth of consideration.
Mention may be made here of Mr. Cave’s process of using raw grain in the mash-tun without any other vessel, brought forward by him in connection with his mashing machine. Full working details of it are imparted by Mr. Cave only to those who are willing to make the necessary arrangements with him. It is no secret, however, that like the second method described here, it is a semi-decoction process. Whatever differences in detail there may be between the two plans, the same general principles apply to both; and the brewer who has mastered these will be well able to conduct a raw grain mash for himself with either a steam masher, a coil, or naked steam.
SACCHARIFICATION UNDER PRESSURE
The two methods of using raw grain, which have been described at some length, are those which will most commend themselves to the brewing trade generally. They are simple, cheap, entail little or no alteration of plant, and there is no patentee to claim a royalty. A review of the subject will, however, be incomplete which confines itself to these two methods only, and makes no mention of the more costly converters which have been introduced, and for which great advantages are claimed.
Probably the best of these is the raw grain converter patented by Mr. Kinder, the well known brewers’ architect and engineer, and as it adopts the principle, new to brewers, of carrying on the conversion under pneumatic pressure, it is worth of consideration in detail. It consists of a very strong, closed metal vessel, with a steam jacketed bottom and a dome-shaped top. Inside the vessel is a closely-fitting rouser, which revolves very near to the bottom and sides, so as to scrape off the thick starch and prevent it burning. This rouser is driven by geared shafting working through a steam-tight stuffing-box in the dome. There is also in connection with the interior of the vessel an air pump, which, by a simple arrangement of valves, can be used either as a compressor or vacuum pump. In addition of course, there are the necessary pressure gauge, manhole, inlets for grain, malt, liquor, steam, and air, and outlet for the prepared grain mixture.
In working the converter the raw grain only is first mixed in the vessel with 33 barrels of liquor per quarter, and kept for three or four hours under a steam pressure of 45 lbs. per square inch, the rouser being kept in motion the whole time. The effect of this is to very thoroughly exfoliate the starch of the grain, and to produce a paste of great consistency, requiring considerable power to keep it stirred. This paste is then cooled to 150 o or a little more, either by the introduction of sufficient cold liquor, or by means of the air pump, now used as a compressor, a pneumatic pressure of 80 lbs per square inch is obtained; the rouser is then stopped, and the whole is allowed to stand all night at this pressure, and as near 150 o in temperature as possible. The following morning when mashing, the now quite fluid mixture, having been first raised to the proper heat, is used as mashing liquor in the usual way, the precautions previously described to prevent the grain from settling on to or underneath the false bottom being carefully observed. The mixture will have lost some heat during the night, but not a great deal.
This method of saccharifying grain is calculated to produce a very complete conversion of the starch. The long standing at or near 150 o in the presence of diastase would alone go far to accomplish this, and the high pneumatic pressure tends to still further increase the diastatic action of the malt. Just as the converting power of acid in the manufacture of glucose or invert sugar is largely increased by pressure, so, Mr. Kinder asserts, is the action of diastase stimulated by the same means. The application of steam pressure being accompanied by great heat, which would destroy the diastase, Mr. Kinder makes use of pneumatic pressure in its place. He claims that the use of his patent avoids the objectionable flavor sometimes noticed in beer brewed with raw grain, but as plenty of excellent flavoured beer is made by other processes, this advantage does not belong to his plan alone.
Mr. Kinder also claims for his converter that, by its use, black and brown malts in the brewing of porter and stout may be entirely dispensed with. He states that if 10 or 15 per cent of malt added to the grain before it is subjected to the steam pressure of 45 lbs. per square inch, some colour and the true porter flavor are acquired. Any deficiency in the colour is to be made up afterwards by the addition of caramel or beer colouring. It is no doubt true that the exposure to 45 lbs. steam pressure for three or four hours would produce considerable caramelisation of the malt sugars, and if this is sufficient to make porter and stout of good flavor without black or brown malt, the gain in extract would be large. But it would not be wise to leave out the black malt entirely, until it is quite certain that the flavor obtained by this means is equal to that from ordinary porter grist.
The one drawback to this process is its considerable expense, both in first cost and working expenses. The converter, including air-pump and other fittings, varies in cost from about from about 70s per quarter of grain converted at one time in a small 2 – quarter machine to 35s, or a little less per quarter for a large one. In addition to this a royalty has to be paid to the patentee on all the material that passes through the machine. The steam power required to drive the rouser through a large pasty mass of thick starch solution would also be very considerable.
SOLUTION OF STARCH BY HEAT
Another process has been introduced from America similar in principle to Mr. Kinder’s, but dispensing with both the steam and pneumatic pressures employed by him. It has been used very successfully on some of the lager-beer breweries in the States, but has not yet obtained much favour in this country. In this case the converter is a semi-cylindrical metal vessel, with a steam-jacket and also a horizontal shaft, provided with revolving arms or rousers scraping the sides and bottom. The rouser being set in motion, finely ground grain or starch is run in gradually with about 10 barrels of liquor per quarter at a low temperature, the steam is turned on in the steam-jacket, and the heat raised to 205 o, the rouser being kept constantly moving to prevent settlement or burning. As soon as the starch is thoroughly exfoliated or dissolved, the heat is reduced to 150 o, either by mixing in sufficient cold liquor, or by substituting a stream of cold liquor for steam in the jacket. When the desired heat is attained, diastase is added, either in the form of malt powder, or a cold infusion of malt, in the proportion of 5 per cent on the grain. The starch solution immediately liquefies, and after a short time of continued stirring to ensure the complete disappearance of soluble starch, is again raised to 200 o or 205 o, then cooled to mashing heat, and used as mashing liquor. The very large quantity of liquor used by this method nearly or quite dispenses with the use of any other mashing liquor.
Here, again, the preparatory conversion, although not carried quite so far as by Mr. Kinder’s process, is very complete; and any small deficiency in this direction would be nearly or quite made up for in the mash-tun. The drawbacks are the size and cost of the apparatus required, and the large amount of power needed to drive the revolving arms when the starch solution is in the pasty condition. This latter might be reduced somewhat by using a small quantity of ground malt or cold malt infusion at the very beginning, in addition to that used later on, so as to prevent the solution ever assuming the very pasty consistency; but if this were done the method would be practically the same as that first described, without the advantages of simplicity and economy in machinery. If malt infusion be used, it should be prepared quite cold, at or below 60 o; there is then no fear of the lactic fermentation which would rapidly set in at a temperature between 75 o and 95 o. This method has been practically used in at least one brewery in England with some success, employing the wort copper as the converter and hand power only for the stirring, but the quantities used were very small, never reaching 3 quarters of grain. For larger quantities steam power and a proper vessel would be found absolutely necessary.
UNPREPARED GRAIN in the MASH
The very simplest of all methods of using grain, namely the direct admixture of ground grain with the malt in the mash-tun, without any previous preparation, is the next to be considered, and it is by no means the least promising. In this, the exfoliating action of heat on the starch cell is of little or no service; the osmotic or diffusive action of diastase through the starch cell wall is alone employed to effect the conversion. The whole work, both of penetrating the starch cell and converting its contents, being thus thrown upon the diastase, the conversion will be much less advanced in the same time by this method than by any other; in other words, the proportion of dextrine present in the wort will be high. This method, standing the mash the usual time, is, therefore, specially adapted to brewing running beers, but, by standing two and a half or three hours, the conversion will be advanced further, and a wort produced fitted for brewing stock beers.
The ratio of maltose to dextrine in the wort as well as the amount of extract obtained, will vary according to (1) the quantity of liquor used; (2) the time of standing of the mash; (3) the heat of the mash; and (4) the description of grain employed (see tables of experiment at the end). When barley or rye is used, the 1st, 2nd, and 3rd conditions have much less influence on the result than with rice or maize, as, owing partly to the presence of a considerable quantity of diastase in unmalted barley and rye, and partly to the large size of their starch cells, they produce a wort differing but little in composition from malt wort, and yield practically the whole of their extract, when mixed direct in the mash-tun without any previous preparation.
The points to be noted in using raw barley or rye in this way are, that they should be pretty finely ground, about as finely as the malt, to enable the diastase to act freely on every part, and that the precautions previously mentioned to procure thorough admixture, and to prevent settling on to or under the false bottom, should be carefully observed. The best initial mashing heat for conversion is 150 o, but barley and rye yield so readily to the action of diastase, that there is no need to alter the usual mashing heats. The chief objection to using raw barley, and to some extent rye also, by this or any other method, is the very large percentage of soluble albuminoids present in the grain. The processes of germinating and kiln drying reduce these soluble albuminoids, so that in malt there is only the proportion necessary to sustain a vigorous growth of yeast, without leaving too much albuminoids matter in the beer. Raw barley can only be safely used in any considerable quantity after having been subjected to a similar thorough kiln-drying at a high heat. The effect of this kiln-drying on the albuminoids of the barley is to make insoluble some of those which were previously soluble, and to convert others into torrefaction or colour products. Some dextrine is also produced on the kiln, the quantity varying in proportion to the heat employed.
A few months ago, Mr. Fordred, of Tottenham, patented a process for manufacturing “torrefied grain” for use in the mash-tun in this way, and a sample of “torrefied barley.” Examined at that time, seemed well fitted for the purpose. The barley was heated in cylinders for a short time, at a temperature much higher than would be obtained on an ordinary liln, sufficient indeed to swell every grain almost to the bursting point. Some corns had quite burst, and presented a broken appearance very similar, though less in degree, to the familiar pop-corn, which children make by roasting maize in wire baskets over a clear fire. This torrefied corn does not yet appear to be in the market, so that little can be said of its practical value or comparative cost.
In mashing rice or maize without any previous preparation, find grinding is even more necessary than in the case of barley or rye, on account of their harder character and the small size of the starch cells. The three conditions of liquor, time, and heat are also of much more importance in their case than that of barley. The quantity of liquor which can be used in practice does not vary very much; two and a half to three barrels per quarter should be used in any raw grain method, and much more than this would make it impossible to exhaust the goods without running too long a length.
Heat is by far the most important factor of the three in using unprepared rice or maize. In some experiments carried out by the writer, in which ordinary rice-flour was used, it was shown conclusively that a temperature of at least 150 o is necessary for a good conversion. By mashing for two hours at 150 o, the extract obtained from a mixture of half malt and half rice-flour was 96.6 lbs. per standard quarter, the maltose and dextrine in the wort being in the ratio of 2.87 of the former to 1 of the latter. By mashing at 140 o the extract obtained was only 66.6 lbs. per quarter, and the ratio of maltose to dextrine 10:31 to 1, showing an exceedingly incomplete conversion as to the total quantity of sugars obtained. Above 150 o the total extract very slightly but progressively diminished, and the ratio of maltose to dextrine rapidly decreased, until by mashing at 180 o the extract had fallen to 89.8 lbs. per quarter, and the wort was more than half dextrine, maltose to dextrine being as 0.92 to 1. By mashing the same mixture of malt and rice-flour, having first thoroughly prepared the rice by boiling it for 15 minutes, the extract obtained was 97.7, and the ratio of maltose to dextrine 3.87 to 1. The malt used in each case was the same, a well-cured malt made from thin-skinned foreign barley, and was of very high diastatic activity. Mashed alone it yielded 91.6 lbs. per standard quarter, with a maltose and dextrine ratio of 5.75 to 1. As the mixture of malt and boiled rice-flour yielded 97.7 lbs. per quarter and the malt alone gave 91.6, the extract obtainable from rice alone would be 103.8 lbs. This corresponds very closely with the percentage of starch present in the rice, determined by means of sulphuric acid, and is practically the full extract obtainable from that sample of rice. Thus it will be seen that when, instead of being previously boiled, rice-flour was mashed at 150 o without any preparation whatever, the total extract was reduced only 1.1 lbs. per quarter. This is equivalent to a loss of 2.2 lbs. per quarter on the rice alone, as the malt in each case may be assumed to yield the same, viz. 91.6 lbs. per quarter. The ratio of maltose to dextrine was also altered by not boiling the rice from [3.87 to 1] to [2.87 to 1].
The full results of these experiments are printed at the end of this volume in the form of a table.
It is clear then that, in the laboratory at any rate, rice-flour can be used unprepared, direct in the mash-tun, without any serious loss of extract – not more than 2.5 per cent. These results have been very largely confirmed in the brewery, but, owing to the incomplete mixture of the goods, the extract was not fully obtained. With a well-mixed tolerably thin mash the extract from rice-flour by this plan should consider ably exceed that from malt of average quality. In order to avoid too dextrinous a wort, the mash should be allowed to stand two hours, or for stock beers as long as 3 hours, at a temperature of 150 o; and to obviate loss of extract from the rice great care must be taken not to allow the heat to get below 105 o.
CONVERSION BY ACID
The only remaining plan of using raw grain in brewing which appears to require notice is what may be called the acid method, in which the starch of the grain is converted by the action of an acid in conjunction with steam pressure. The product of this conversion carried to its full extent is dextrose or grape-sugar only, but by arresting the process at the proper moment a product can be obtained containing more or less dextrine, and in some cases maltose as well. The material produced by the Manbré Saccharine Company, Limited, is a good example of complete conversion, the percentage of dextrine being usually very low. Johnson’s Saccharum Company, Limited, produce two articles, one an ordinary glucose in lumps, containing but little dextrine, the other a highly dexrinous substance, in which a considerable quantity of maltose is also present. The foreign glucoses are generally pretty fully converted.
Professor Graham has repeatedly stated in his Lectures on Brewing, delivered at University College, that the dexrines obtained by means of acid, although chemically indistinguishable from those produced by heat on the kiln, are of a much less stable character when subjected to the influences of fermentation. It will therefore be well, in purchasing manufactured glucoses for stock beers, to select those which consist as largely as possible of dextrose or grape-sugar, and contain but little dextrine, relying on the diastase in the mash-tun to produce the dextrine requited in the beer. For running beers, the dextrinous saccharums may have advantages of their own.
Dextrose or grape-sugar is rapidly and almost entirely fermented by the yeast organism into alcohol and carbonic acid, so that commercial glucoses are fitted rather to compensate for an excessive quantity of albuminoids in the malt and to produce a clean alcoholic beer than to give fullness of flavor.
Converting apparatus is constructed with a view to carry on the acid method in the brewery, but it is very costly. Manufacturers invariably use animal charcoal filters to purify and decolourise their product. A brewer employing his own acid-converting apparatus would have either to do the same as some cost and trouble or to use the syrup- obtained without treating it with charcoal. On the other hand, he need not dry his syrup to the solid condition, and would thus save the cost of vacuum-pans. Sulphuric acid is almost always the agent used, common chalk being employed to neutralize it. The process is so totally different from any to which the brewer is accustomed, that on the whole it is probably wiser to purchase the manufactured article than to attempt to make it in the brewery.
Mr. Alex. Manbré has patented a method for use in breweries, in which the converting agent is produced by adding sulphuric acid to bone ash. He claims that the results are identical with those obtained by a diastatic conversion; but as the sulphuric acid is used in considerable excess it must aid very largely in the process, and the products will probably not differ in any great degree from those given by the ordinary sulphuric acid method of converting grain. The plant required is somewhat costly.
COMPARISON OF MATERIALS
Having described somewhat fully in the previous pages the principal methods of using raw grain, it remains to compare the different descriptions of grain which are available for the brewer’s use. The two points to which attention should be chiefly directed are the effect on the flavor and keeping qualities of the beer, and the cost, taking the extract obtainable into consideration. Wheat, oats, rye, maize, rice, and barley are the cereals which are common in this country, and each will be considered in turn.
The following table shows their composition as given by Gilbert, but neither the wheat nor the barley can be considered as average samples; 10.9 is a very low percentage of albuminoids for wheat, and 13.2 is somewhat high for malting barley.
|Gum & Sugar||3.8||4.2||5.7||11.3||2.9||1.6|
In estimating the extract obtained from them, the figures given are in almost all cases the result of actual experiment made by the author for the purposes of this work. Corn of good average quality is assumed to be used in every instance excepting that of barley, in which case, as the best barleys are used exclusively for malting, good grinding barley has been taken. Average market prices at the present time have been employed in the calculations.
Wheat is a highly nutritious grain, but not well suited for brewers’ purposes. It contains a large quantity of albuminoids substances, the percentage varying from 10 to 17 per cent, according to the quality of the wheat and the soil on which it is grown. These albuminoids are chiefly fibrin, and are not calculated to improve the stability and soundness of the beer in which they are present. At the present time wheat is very cheap; taking an average price of 45s per quarter of 496 lbs. (62 lbs per bushel), the cost per standard quarter of 336 lbs., is 30s. 6p. Assuming that this will yield 90 lbs. per quarter, 4.05 pence is the cost per lb. of extract. Even at present prices this does not compare favourable with other cereals; in dearer seasons wheat is quite out of the brewer’s reach.
Oats are even richer in albuminoids than wheat, and contain also 5 per cent or more of oily matter. They are poor in starch, but the large proportion of husk is calculated to assist in the drainage of the goods. They have been used successfully with other grain to improve the drainage, but on account of the high percentage of albuminoids, they should not be used in any large proportion. Taking 20s. as the present price of 38-lb. oats, the cost per standard quarter is 22s. 1d., and the extract at 80 lbs. per quarter would cost 3.31 pence per lb.
Rye, excepting for green fodder, is not much grown in this country. It is used largely on the Continent for both bread-making and distilling, and the character of its albuminoids makes it well fitted to nourish and stimulate the yeast plant. The spirit made from it has a very objectionable flavor, and this flavor would probably also be found in beer made from it in any considerable proportion. The price per standard quarter is about the same as oats, the extract 80 or at most 85 lbs.; the cost per lb. of extract would vary very little from oats, the difference being slightly in favour of rye.
Maize is well suited for the brewer’s use, but is just now very scarce and dear. It is rich in starch and comparatively poor in albuminoids, the latter being only 8 or 9 per cent. The proportion of oil is considerable, from 4 to 5 per cent, and this to many minds, makes ordinary maize meal unsuitable for brewing. It is, however, not certain that the oil has much effect on the flavor of the beer; is insoluble in water, and remains behind in the grains. At the present market rate of 37s. per quarter of 480 lbs., the standard quarter costs 25s. 11d., which at 85 lbs. extract, gives 3.66 pence per lb. of extract. In ordinary seasons, however, 30s. is nearer the average market price, in which case the standard quarter would cost 21s. only, and the lb. of extract 2.96 pence.
A special preparation of maize meal, known as Robertson’s germless maize, is at present largely used by brewers, and in many respects it is well fitted for their purpose. In its manufacture the germ and husk are removed by patent machinery, the remainder of the corn being ground to the size of fine gunpowder. In this condition it is easily prepared for mashing, either by the outside converter of the mash-tun method, and as there is no find flour in the meal, there should never, with ordinary care, be any difficulty in draining. As the oil is situated almost entirely in and around the germ, the removal of the latter largely reduces the percentage of fatty matter. As has been stated, in maize it is from 4 to 5 per cent, whilst in Robertson’s meal it is not more than 1.25 per cent. The oil is pressed from the germ and husk as maize-oil and the cake resulting is an excellent feeding material. The present price of this meal is 29s. 6d. per standard quarter of 3 cwt., which, at 95 lbs. per quarter, gives 3.72 pence per lb. of extract. As with ordinary maize meal, the price would no doubt be much less in more favourable seasons.
Rice is the richest in starch and the poorest in albuminoids of all the cereals now under consideration; the latter amount to only 6 or 7 per cent. It is almost free from flavor of any kind, and readily assumes the flavor of the malt with which it is mashed. There is a somewhat prevailing impression that beer brewed from rice is thin in character, but, as has been mentioned before, this depends very much upon the ratio of maltose to dextrine in the wort. If dexrine is present in sufficient quantity, the beers will be round and full. The method of mashing rice flour direct in the mash-tun without any previous preparation is well adapted to produce a dextrinous wort, indeed the usual time of standing the mash must be prolonged a little, or there will be too much dextrine present. The present price of good rice-flour is 21s. per sack of 280 lbs., which is equivalent to 25s. 2d. per standard quarter. The extract from this should be from 100 to 105 lbs., and taking 100 lbs. as a safe average, the cost per lb. of extract is 3 pence. For the direct method of using rice just referred to, rice ground to flour is best adapted, but when any previous saccharifying or preparing process is employed, the drainage will be improved by using rice ground in granular form, like Robertson’s germless maize meal. Mr. Pavitt, of the East London Rice Mills, is willing to supply rice ground in this manner at a slightly increased cost. It ought, however, to be procurable at the same price as the flour, and if there were any demand for the granular form it would no doubt be supplied without extra charge.
In some experiments which the writer has recently made, very satisfactory results were obtained by using unground commercial “broken rice” of good quality in conjunction with malt. The extract from the broken rice prepared by digesting for thirty minutes at 194 o with 10 per cent of malt, and then cooling to mashing heat before mixing in the rest of the malt, was very slightly better than when the rice was boiled hard for thirty minutes before mashing, but the difference was scarcely worth noticing. As the broken rice used in these experiments can be bought for 6s. 9d, per cwt, or 20s. 3d. per standard quarter, this is by far the cheapest material at the present procurable. The yield should be 95 lbs. per quarter, and the cost per lb. of extract 2.56 pence.
Barley is the only grain which is usually malted for brewing purposes, and it therefore naturally suggests itself as well suited for use as a raw grain. It has, however, been already explained that, owing to the high percentage and soluble character of its albuminoids, it is not fitted for brewing without some previous treatment. Thorough kiln-drying at a high heat reduces some of these albuminoids to the insoluble condition and converts other into colour products, and is therefore a very suitable was of preparing barley. But it would be better still to roast the barley slightly, either by Mr. Fordred’s process or by some other simple means. When roasted, barley can be ground between smooth rolls almost as easily as malt. By either of these processes a small quantity of dexrine is formed, and the raw flavor of barley obviated. It has been pointed out on page 46 that barley is easily converted, and can therefore be used direct in the mash-tun without any loss of extract. In estimating the comparative value of barley, it must be remembered that the best barleys are of more value for malting than for use as raw grain, and that therefore the field of selection is confined to the lighter sorts. The best for use unmalted are either good English grinding barleys, or some of the lighter French or North European sorts. Egyptian barley would also answer the purpose well. In some seasons stained Scotch barleys which will yield high extracts can be bought very cheaply, but care should be taken to see that they are not grown as well as stained. In no case should unripe barleys be chosen. At present market rates, suitable material can be bought for 30s. or less per quarter of 448 lbs. equivalent to 22s. 6d. per standard quarter. Taking the lower figure, 3.6 pence is the cost per lb. of extract.
In addition to the different descriptions of raw grain which have been described, there are on the market several sorts of prepared grain, which are largely advertised, and which require some consideration. Those best known at the present moment are Gillman and Spencer’s and Southby’s so called gelatinized grain. They are prepared by subjecting rice or maize for some time to high steam pressure and afterwards drying them by some suitable means. Owing to the insufficient quantity of water present during the steaming process, the starch is not gelatinized or exfoliated as is commonly supposed; the steaming and subsequent drying produce a very small quantity of dextrine, but the bulk of the grain is practically unaltered. So far as the extract is concerned, these materials are suited for brewing, either by the outside converter plan described in these pages or by the mash-tun process given next. They will yield about the same extract as ordinary granulated rice or maize of similar quality. They are not fitted for direct admixture with the malt, unless previously finely ground, in which case they stand on the same level as ordinary rice or maize flours. Southby’s material is prepared in this finer form, as well as in the granular condition; it is then called “Brewing Meal,” and an extract of 86 to 90 lbs. per quarter is claimed for it used in this way. The price of these materials is from 30s. to 36s. per standard quarter, and as their yield would not as a rule exceed 95 lbs., the price per lb. of extract would be from 3.79 to 4.54 pence.
Mr. Beans is about to introduce to the brewing trade a form of prepared rice which is new. In this case broken rice is digested in the cold for two days with a very weak solution of sulphuric acid. The acid is then removed by copious washing, and the rice is dried by means of patent machinery at a temperature of 310 o. This plan closely approaches the commercial method of making dextrine or British gum from starch, and by its means the rice is reduced to a friable condition, in which it can be ground between ordinary malt rolls. A large quantity of dextrine is produced by the high heat used. This prepared rice, mashed direct with malt, either ground or used unbroken, readily yields and extract of 95 lbs. or a little more. Assuming the price at which it will be sold to be 36s. per standard quarter, the cost of the extract will be about 4.54 pence per lb. The result of experiments is to show that this dextrine, although readily soluble in the mash-tun, is converted to a very small extent only, if at all, into maltose, and it is therefore a question which practical experience alone can decide whether wort containing so very large a proportion of unaltered dextrine is suitable for brewing sound beer. It has also to be decided whether the use of sulphuric acid in the early stage of the manufacturing process does not give to this dextrine the unstable character possessed by the dextrine present in some acid-made glucoses and saccharums.
From these figures it will be seen that the present time rice, whether in the form of “broken rice” or as rice flour, is by far the cheapest form of raw grain. In ordinary seasons, maize would come next, but this year it is surpassed by oats, barley, and rye. Excepting as an aid t the filtering of the goods, oats are not well adapted for brewing beer, their very high percentage of albuminoids being undesirable. Barley, slightly roasted or thoroughly kiln-dried, is admirably suited for brewing; it can always be obtained at a moderate price, and although not so cheap as rice, it is converted in the mash-tun more easily; it will give a better flavor, and, ground to the same degree of fineness, will drain somewhat more freely. Wheat and rye are practically out of the question. For purposes of comparison the cost of malt may be taken at 42s. per quarter, being about 6d., or rather less, per lb. of extract.
INVERT SUGAR AND SACCHARUM
When raw grain is used in any considerable proportion, it is desirable to run longer lengths than are usual with malt alone, so as to prevent the last runnings being of too high a gravity. For this purpose raw and invert sugars, saccharums, and glucoses are useful, but of these, inverted cane-sugar is undoubtedly the best. Cane-sugar, when inverted, consists always of the two substances, lævulose and dextrose, in equal proportions. Of these dextrose is easily fermented, and in the fermenting-tun is very quickly broken up into alcohol and carbonic acid. Lævulose, on the other hand, is much more stubborn, and much of it remains in the finished beer, giving that fulness and sweetness which are generally found in beers containing much invert sugar. Raw sugar is not so well fitted for brewing as invert sugar, for, before it can be fermented, it must be inverted by means of the yeast organism. This work is somewhat exhausting to the yeast, and when much raw sugar is used, the yeast is apt to become weak and require changing.
Garton, Hill and Co.’s lævo-saccharum is the best known invert sugar, and is a very perfect article, but is dear. Raw sugar can be inverted in the brewery at very little cost, by boiling in a wooden back with a small quantity of sulphuric acid, chalk being used afterwards to neutralize the acid. By selecting for this purpose those raw sugars which already contain some invert sugar, and which being ill-fitted for the refiner, are cheap, a large saving can be effected. At from 16s. to 20s. per cwt., good sugar for his purpose can be bought, giving, when inverted, 90 to 95 per cent of invert sugar, whilst the commercial article, at a much higher price, contains a great deal of water and only 75 per cent or a little more of invert sugar.
Before undertaking to invert sugar in the brewery, it will be necessary to obtain full instructions from a competent authority; the quantity of acid required varies according to the character of the water used. In buying invert sugar some guarantee should be procured that cane-sugar only, and not beetroot sugar, has been used in its manufacture. Beet-sugar has a very unpleasant and persistent flavor and smell, and is not fit for brewing with.
Southby’s condensed wort is also a suitable material to use for the purpose of increasing the lengths run. It is prepared from maize converted, not by means of acid, but by the diastase of malt. It contains, consequently, maltose and dextrine, but not glucose, and is thus to some extent an approach to ordinary malt wort. Other saccharums and glucoses have been referred to when speaking of the acid method of conversion.
Some differences of opinion have arisen between dairymen and brewers as to the value of grains in which there is a proportion of raw grain, and in one case a lawsuit of some magnitude resulted from these differences. It would appear that when barley or maize is used, the grains are in no way damaged; the unconverted residue from these is rich in albuminoids, and contains some fatty matter, as much or more than malt grains. When these are used no objection should be raised by the cowkeeper to paying the same rate per quarter for raw grain residue as for malt grains. The case is different with rice. Owing to the low percentage of albuminoids and the almost entire absence of oil, rice residue has very little feeding value, and it would be but fair to make some concession in the price of the grains.
In conclusion the writer hopes that, although he may not have persuaded those who disapprove of raw grain as a brewing material to change their view, he has shown that it may be easily and profitable employed. He has endeavoured to place before he practical brewer something of both the theory and practice of using raw grain, burdened as little as possible with scientific technicalities.
ENGLISH INFUSION PROCESS
Reprinted from Professor Graham’s Paper on Lager Beer
|No. I – Influence of Initial Heat|
|Temperature deg. F||Maltose||Dextrine||Total Sugars|
|Malt No. 1||150||47.47||10.70||58.16|
|Malt No. 2||140||52.81||12.08||64.89|
|Malt No. 3||140||51.36||10.60||61.96|
The malt was mixed with cold water and the temperature raised in 30 minutes to the various heats given; and the infusion process then conducted for two hours at the respective heats .
|No. II – Influence of Quantity of Water|
|Malt 100 Temperature 140 oF Time-2 hours|
|Quantity of Water||Maltose||Dextrine||Total Sugars|
|Malt No. 1 1000||53.56||11.39||64.95|
|Malt No. 2 1000||52.81||12.08||64.89|
- In this experiment, a portion of the water was allowed to evaporate, and therefore the real quantity of water was less than 100, hence the great fall in the amount of maltose.
| No. III – |
Influence of Time
|Malt 100||Water 1000||Temperature 145 oF|
|Duration of Mash||Maltose||Dextrine||Total Sugars|
|Malt No. 1||30 minutes||48.60||14.61||63.21|
|Malt No. 2||30 minutes||49.99||14.98||64.97|
|Malt No. 3||30 minutes||47.46||13.89||61.35|
Temperature, Quantity of Water, and Time are however, not the only factors, as I termed them, of the hydration process to be considered; we have three others:
- The lightness or heaviness of the land, together with favourable or unfavourable maturation conditions, all of which influence the activity of the hydrating albuminoids.
- The amount of growth of the plumule on the germinating floor, since pari passu with its growth do we increase the diastatic action of the albuminoids, due to the transfusion action which takes place from the cells of the plumule through the successive cell layers, until even the interior cells are influenced; thus the albuminoids are degraded and become active hydrators. The English maltster in taking the plumule as a guide in the amount of change produced is on surer grounds than the foreign maltster, who takes the rootlets as the index of internal change.
- Lastly, the final heat on the kiln floor varies the products of the mash tun, the higher the temperature the more dextrine is formed on the kiln, and at the same time the soluble albuminoids are altered and lose some of their diastatic action in the mash-tun.
Thus even with the infusion process we have the means of modifying the products of the mash-tun; and the use of rice, and other materials, high kiln dried or otherwise, will henceforth give additional means of modifying the results. The use of glucoses, cane sugar, and invert sugar, which for some years has been allowed by our fiscal laws, of course all tended to the production of alcohol. TABLE IV gives some of my results on the use of unmalted grain.
|No. IV – Influence of Diastase|
|Malt or Substitute 100||Water 1000||Time-2 Hours|
|A||Temperature 145o F|
|Barley 100%||Barley 90% Malt 10%||Barley 80% Malt 20%||Barley 50% Malt 50%|
|Rice 25% Malt 75%||Rice50% Malt 50%||Rice75% Malt 25%||Malt 100%*|
|* Rice = 72% Starch|
|Raw||Boiled||High dried||High dried||Rice|
|Barley 50% Malt 50%||Barley50% Malt 50%||Barley 50% Malt 50%||Boiled 50% Malt 50%||Boiled 50% Malt 50%|
|Barley 25% Malt 75%||Barley 50% Malt 50%||Barley 75% Malt 25%||Barley 25% Malt 75%||Barley 50% Malt 50%||Barley 75% Malt 25%|
|High Dried||High Dried||High Dried||High Dried||High Dried||High Dried|
|Barley 25% Malt 75%||Barley 50% Malt 50%||Barley 75% Malt 25%||Boiled 25% Malt 75%||Boiled 50% Malt 50%||Boiled 75% Malt 25%|
Nota bene – The malts and barleys in series A, B, C, D, were different, though the same for any given series. It will be seen that no advantage is obtained by boiling barley previous to mashing, owing to the activity of the albuminoids of barley; with rice, boiling is essential.
|No. V – Influence of High Kiln Heats on|
|Infusion Products of Malt|
|176o F||212o F||248o F|
|Colouring Matters, ash, &c.||1.49||1.38||1.32|
|Total dry solids||76.07||74.40||73.80|
|RESULTS OF EXPERIMENTS BY THE AUTHOR ON THE USE OF|
|RICE-FLOUR MASHED WITH MALT AT VARIOUS TEMPERATURES|
|Maltose per cent||Dextrine per cent||Maltose / Dextrine Ratio||Extract per quarter|
|1. Malt alone, mashed 2|
|hours at 140o F||52.81||9.18||5.75 : 1||91.6|
|2. Half malt and half|
|boiled, mashed 2 hours|
|at 140o F||53.91||13.90||3.87 : 1||97.7|
|3. Half malt and half|
|mashed 2 hours at|
|140o F||43.10||4.18||10.31 : 1||66.6|
|150o F||49.34||17.19||2.87 : 1||96.6|
|160o F||39.47||25.82||1.57 : 1||94.1|
|170o F||39.47||24.43||1.61 : 1||94.3|
|180o F||28.84||31.28||0.92 : 1||89.8|
|190o F||30.00||32.72||0.91 : 1||92.6|