A brief note to start . . . In the previous article on “Brewing in Belgium and Belgian Beers”, the author was rough on Belgian brewers as being so cheap as to not bother with cleaning their breweries. Now, over 20 years later and in a war which puts brewers in the position of a shortage of the necessity materials, the Belgians just might have something to offer.
MEETING OF THE LONDON SECTION, HELD AT THE IMPERIAL HOTEL, RUSSELL SQUARE, W.C., ON TUESDAY, MAY 14th, 1918.
Mr. P. K. Le May in the Chair.
The following paper was read and discussed: ~-
A Belgian Mashing System Suitable for Light Beers.
By George M. Johnson.
To understand the present it often becomes necessary to study the past. That is true in a peculiar degree of the mashing process which forms the subject of my paper.
A century ago, as a result of one of the many territorial and political rearrangetnents following on the overthrow of Napoleon at Waterloo, Belgium formed the southern portion of the Kingdom of the Netherlands; the seat of the Government was at Amsterdam; and the reigning monarch was William I—of anything but blessed memory in brewing circles, for he was signatory to, if not otherwise responsible for, one of the most ridiculous and vexatious Excise laws that ever disgraced the annals of fiscal interference and fiscal stupidity. That law was dated 1822.
But—you will remind me—the Belgians, by their Revolution of 1830, threw off the Dutch yoke, regained their independence, set up a Government of their own, this time in Brussels. That is so. But it takes more than a revolution to alter brewing. And, as a matter of fact, the Revolution of 1830, which changed the map of Europe, created the independent Belgium for which we are now at war, proved, as far as brewing was concerned, to be a storm in a tea-cup, to which the mash-tun, as befits it, remained stolidly superior. National independence brought with it no equivalent emancipation for the Belgian brewing industry; the ridiculous old Dutch law remained; it was adopted without material alteration by the now Belgian Legislature, which at the time had other fish to fry. And like many other stupid things, that law was long-lived. It was not repealed until 1885. In the interval its influence on Belgian brewing practice was profound.
The root of that influence lay in the fact that the beer duty was a fixed duty per brewing, levied on the capacity of the mash-tun. Two things followed as a direct consequence—each brewer erected as small a mash-tun as was compatible with the volume of his trade, and then essayed to fill it as full as possible of grist or of goods. For the space of some sixty years (1822-1885) the bent minds in the Belgian brewing world seem to have concentrated on the problem of getting a quart into a pint pot. And I must say that, amongst them, they produced some very elegant solutions to that problem.
In the first place, if you fill a mash-tun as full as possible of grist, there is not much room left for the liquor. The mash resembles a sponge, out of which, by hook or by crook, you must coax or squeeze a little wort. This the brewer accomplished by various devices. He found one contrivance, at least, ready to hand in the centuries-old “brewers’ basket.” This basket was pushed down on to the goods, which, as a result of the stiff mash, were very compact. In the hollow or basin thus formed by the basket was inserted a flexible pipe, connected with a hand-pump. Through the meshes or strands of the basket flowed a turbid or milky wort, which, by means of the pump, was raised to the thick or turbid wort copper. In this copper was a chain stirrer of some sort, to keep the starchy material off the bottom and pro rent its burning. As extraction proceeded by means of the basket, more liquor was added to the goods. Mashing-up with hand-oars and extraction by means of the basket proceeded alternately. Some of the worts were also got away through the mash-tun plates, and from the underback were pumped up to the turbid-wort copper.
These worts were turbid for two reasons. By the very fact that little liquor could be got into the mash-tun, the temperature of the first mixture was low. Any attempt to use liquor hot enough for what we should call a striking heat would have resulted in a set-mash. Further, raw grain, wheat and rye especially, was often mixed in with the barley malt, ground in with it, through stone mills, to get a good mixture. Even with malt alone the temperature was not, during the first phases of the mashing, high enough to gelatinise any considerable proportion of the starch. Consequently the worts, charged with ungelatinised starch and other matters, were, at these preliminary stages of the mashing at all events, never bright but always turbid. Subsequently the turbid worts, after being brought to the boil in the chain-copper, were clarified by repassage over the goods, and the resulting bright or clarified worts were then pumped to another copper—the bright-wort copper.
You are familiar with the general appearance of the brewer’s basket. There is in Brewers’ Hall a very fine oak carving, dating back I suppose to 1673, representing the emblems or insignia of the brewer’s profession. In that carving the basket figures prominently, with the mashing oars and other brewery utensils. In Flanders it is still called the “tossing-basket,” a term which betrays its origin; it was originally the basket used in the vineyards to toss the trodden grapes and so extract their juice.
In 1822 there were, in Belgium and elsewhere, probably only baskets and hand-oars. But later, ns machinery was gradually introduced into breweries, there came improvements in the methods of extraction. Apparatus known as “extractors” were invented. The primitive form of extractor seems to have consisted of a series of perforated rectangular vessels, somewhat of the shape and size of train foot-warmers. During mashing these were suspended over the tun, so as not to occupy any of its dutiable and consequently valuable capacity. The mash all in, the extractors were forced down into the goods, much on the principle of the baskets. Later, the Excise having allowed a rebate equal to the volume of any internal mashing machinery, extractors were mostly made in the shape of hollow perforated copper discs, much like pairs of cymbals clapped together. These discs were fixed on a hollow horizontal shafting, forming the opposite arm to the raking machinery, rotating and travelling round the tun with it. The turbid worts escaped through the perforations of the discs, and were carried by the hollow shafting to the central upright (also hollow) supporting the raking and extracting machinery, whence they flowed to the underback. As the tun was brim-full of stiff mash, there was, with this form of extractor, always a tendency to slopping over at the periphery or edge of the tun, owing to the centrifugal action set up by the circular motion of the raking and extracting machinery. This was disadvantageous, as it tended to reduce the amount of grist or mash that could be conveniently dealt with in a tun of given capacity. An inventor then hit upon the ingenious idea of making the extractor in the form of a hollow worm or Archimedean screw—perforated, of course—and rotating with the hollow shafting, through which the turbid worts escaped. The direction of the screw or worm was be set that the goods were constantly pushed towards the centre of the tun, and there heaped up in the shape of a cone, at any rate during the first phases of the mashing. This device considerably increased the effective capacity of any tun. In order to further increase the volume of stiff mash thus heaped up in conical shape on the surface of the goods, the mash-tuns were made very shallow. Obviously, as the area of the base of the cone increased, so did its volume, and, as a consequence, a greater weight of grist could be mashed into a shallow tun than into a deep one of the same capacity. Extractors are still to be found in old-fashioned breweries, especially where raw wheat and barley malt are mashed in together—a practice in favour of which there is a good deal to be said though it is not as a rule economical.
The next obvious improvement that would suggest itself as a means of making the best use of the dutiable capacity of the tun would be to bolt the grist, or part of it. Bolting was introduced before my time, nor can I now remember to what extent, if any, it was allowed by the Excise; but it was practised, and it spoiled the buoyancy of the goods. As a result, it became very necessary to re-add the husks or some sort of chaff to the tun, as room was made for them by the successive withdrawal of the turbid mashes. The addition of chaff facilitated drainage during the subsequent bright-wort mashes, and improved the filter bed for clarifying the turbid worts, when, later, they were repassed over the goods after boiling. The Excise, in any case, allowed this use of husks or chaff. Wheat chaff, that is the outer envelope of the grain separated by threshing, was most favoured in the olden days, and is still largely used, although some brewers now prefer rice husks, owing to their superior rigidity.
You will notice that, by these various means, we are already appreciably nearer the ideal quart in the pint pot that just now you believed to be impossible. But there was a further approximation to this ideal. Both the law and Excise regulations made provision for the use of raw grain other than that directly mashed in with the wait in the tun. For this purpose, a raw-grain copper, or “flour copper” as it was then called, might be used. This vessel was considered as a mashing vessel for the purposes of the duty, but, so as to allow space for the proper mixing of the raw grain and head-room for boiling up, duty was charged not on its total capacity, but upon some smaller volume considered as its effective capacity. This concession naturally led to the invention of some peculiar mechanical and other devices for the manipulation of the raw-grain mashes, the object in view being always the same, viz., to mash the largest possible amount of grist in vessels of the smallest possible capacity, thus reducing the duty per barrel of beer.
Effect of Reactionary Legislation on Belgian Brewing Industry and Practice.
I have not troubled you with this retrospective survey on account of its historical interest, but because the accumulated effects of the old law, both on Belgian mashing and on the Belgian light beer industry, have a very direct bearing on our subject.
Firstly, as to its influence on the character of the beers: The constant tendency to overcharge the vessels, to deal with excessive quantities of materials in too restricted a mashing space, naturally led to some very imperfect conversions, to some very dextrinous not to say starchy worts, with, as a general result, high bung-weights for the original gravities and correspondingly full beers. So much perhaps may be said to the credit of the old legislation. Against those advantages must be placed poor extracts, and various defects and maladies to which the beers were peculiarly liable but which need not detain us.
Secondly, as to the influence of the law on the prosperity of the brewing industry as a whole: It was admittedly disastrous. Brewers of the older generation have frequently told me how, when a colleague found a way of mashing more grist for the fixed duty, he would be tempted to lower the price of his beer and be secure some of his competitor’s trade. When the competitor, in his turn, discovered the method or improved upon it, he returned the compliment. Then gravities would be reduced to meet the lowered prices or the new costs of competition. And so it went on, gravities and prices falling alternately, until, in the course of years, Belgium enjoyed, and still enjoys, the doubtful advantage of making the lightest beers at the very lightest prices.
Further, under the old law, it was impossible to brew English beers at prices that could compete with England or lager beer that could match the German article. Up to 1885 the high class beer trade, for the best cafès and so on, was thus monopolized by the foreigner, much to the Belgian brewers’ discomfort. Since 1885, as you know, there has been great progress; many Belgian brewers now brew lager beers, or did so before the war, that are second to none. You can also still obtain many of the good old-fashioned beers of high gravity, for which there always was and always will be a demand. But beside these special beers flourishes an enormous trade in cheap light beers for family and small public-house trade.
Repeat of the Old Law.
Well, all good things come to an end, and even bad ones. In 1885 the old law was repealed, mainly owing to the exertions of the Brewers’ Associations, and notwithstanding opposition, including, of all people, that of the Excise! Of whatever nationality, the Excise seem to have inherited the beat traditions of the Medes and Persians. The new law, despite many reminiscences of the old and a mass of fiscal verbiage, is really progressive. The duty is levied, much as in England, on the yield, that is on the gravity of the worts multiplied by their volume, a basis which at any rate is fair to all.
The old law, with its bars to progress once out of the way, the Belgian brewers in 1880 thought that the millennium was come, and that there was nothing further to do but enjoy life. Things however did not turn out quite so satisfactorily as they had anticipated. The customers, with one accord, began to complain. The beers were no longer what they were; they were thin. What had happened? Many things. The old restrictions removed, the brewers had increased the capacity of their mash-tuns, or what amounted to the same thing, mashed less at n time in the old tuns. With a much more fluid mash and much greater facilities for getting a rapid and complete conversion, the composition of the worts had changed, and the beers over-attenuated accordingly. Under the old law a brewer would mash the equivalent of one quarter of malt to every two barrels of mash-tun capacity. You may judge of the stiffness of the mash when you remember that for an English tun you allow about 3½ barrels capacity per quarter. He now cut down that quantity to one-half or one-third. Other brewers bitten with a passion for novelty or reform, started making their malt on the English system: well grown up, slowly kilned, friable, and tender, a malt that saccharified with a rush as soon as conversion temperatures were reached in the mash-tun. Nothing surprising, therefore, that the beers—of light gravity, you will remember, i.e., anything from 1040 down to 1025 or less—now fully attenuated, tasted thin. Many of the brewers were so disgusted that they reverted, temporarily at all events, to the old methods of mashing, and overfilled their tune as before.
Things however gradually got explained and tended to right themselves; and as a net result we have the Belgian “turbid wort” mashing process as practiced to-day in the great majority of the breweries of Belgium and in many of those of northern France.
Of course, with reasonable quantities of grist we no longer require extractors nor any paraphernalia of that sort. Our simplest plant differs but little from that found in English breweries. It consists of a mash-tun fitted with external masher and internal rakes, sparge, false bottom, etc.; two coppers, one for bright and one for turbid wort, the turbid-wort copper alone being fitted with a chain or propeller; an under-back; and a wort pump. The only thing peculiar about the wort pump is that it must take turbid or even fairly thick worts. If the mash-tun is on a lower level than the coppers, the pump raises the turbid and bright worts from the under-back to the coppers. When the mush-tim is placed above the coppers the pump redelivers the turbid worts, after boiling, to the tun.
Details of the Process.
Given the above plant, the mashing process is as follows:—Cover the plates with liquor at 110—120° F. Mash in, through outside masher, with liquor at 120—130°F. fairly stiff (say 1½ barrels at the most per quarter) to get 100—110° F. initial in the goods. Rake for 10 minutes or more to get a good mixture with diastase, preformed sugars, etc., more or less in solution. Let stand 30—45 minutes. This rest the Belgians call the “peptonisation” and the Americans the “protein” rest. The proteolytic enzymes of the malt—especially Belgian malts—are active at this temperature; solubilisation, degradation of the albuminoids takes place. Of the resulting products, some are permanently soluble, and therefore not coagulated in the copper, and of these some nourish the yeast, while others are supposed to remain in the beer and give it softness and body. Some of these, or perhaps other bodies formed or extracted later, seem to favour head retention. Acidity, of course, increases; in some processes it is allowed to proceed to a special extent so as to make up for the dilution, when brewing weak beers, of the natural acidity of the malt. Butyric and lactic ferments are active, especially with malts less antiseptically kilned than is the case in England. If the malt is very steely, or where raw wheat is mixed in with the malt, the preliminary mash, instead of being taken tepid, is token cold. Whether cold or tepid, starch granules absorb water and swell up. There is some stimulation of the diastase. Such, stated briefly, are the general effects of this preliminary cold or tepid mash.
After, say 40—45 minutes’ test, the rakes are started again, and from one to two barrels of liquor per quarter are underlet. This liquor may be at 150—170° F. if we are using malt alone. It is colder if any raw wheat is present in the mash or when dealing with a steely malt. The object, with malt alone, at any rate, is to get not more than 120—125° F. in the tun.
(If worked out it will be found that the temperatures and volumes given for the liquor are more than sufficient to obtain 120—125° F. in the tun; but what with iron tuns, relatively small mashes. standing, and severe raking, there is great loss of heat by radiation; so that in practice the temperatures named are very generally necessary.—Author.)
The flow of underlet liquor is then stopped; the rakes continue running, taps are set, and the turbid wort escapes through the plates into the under-back, whence it is pumped up to the turbid-wort copper. With the turbid wort goes off a lot of diastase. Its relation to the total amount of diastase available in the tun will vary with the volume of liquor used and the number or volume of turbid worts withdrawn. That number and volume, and their temperature, vary with the materials used. For an all-malt brew, one turbid wort is sometimes sufficient. Where much wheat is mixed in with the malt, several mashes at correspondingly low temperatures are made and the turbid worts there from drawn off before any very considerable heat is reached in the tun, one of the objects being to withdraw as much ungelatinised starch as possible, and give the rest time to swell up before heats are used that would, if applied too early, inevitably set the goods.
As soon as the turbid worts are off the tun, liquor at or near the boiling point (for an all-malt mash) is now underlet so as to push up the goods to 158° F., at which temperature the tun is allowed to stand for from 45 to 60 minutes. Mark that temperature. It is higher than our English initial of 150″ F., and it exerts its influence on goods previously deprived of a good part, often of the major part, of their diastase, thus retarding hydrolysis. Further, Belgian malts are harder than English; a good deal of their starch has therefore resisted conversion at the lower and intermediate temperatures through which the goods have passed during the mashing-up processes. The hard ends of the malt have certainly resisted gelatinisation, and consequently conversion, during the passage from 120° F. through the optimum saccharification temperatures of 140—150° F.; and, having resisted, their conversion, if their starch now yields, takes place at 158° F. As a total consequence, the worts from this mash are fairly dextrinous. Curiously the Belgians call this infusion at 158° F. their “sacchariflcation” mash; it is a somewhat loose term but interesting, because it shows that they regard the starch as having resisted the previous temperatures. After allowing the tun to stand, as we said before, for 45—60 minutes at 158° F., taps are set and the wort—a bright wort this time—is pumped up to the bright-wort copper.
While this has been going on in the tun, the turbid worts have been gradually heated up to the boiling point in the turbid-wort copper. If the malt was steely, or if any raw wheat was used, the brewer will have allowed the turbid worts to stand in the copper for 20 minutes or so at 105—176° F., so as to allow the liquefying diastase to act on any unconverted starch before pushing up to boiling. The boiling temperature reached, the turbid worts are allowed to simmer until required. Gelatinisation of any starch that may have resisted the lower temperatures will certainly be completed during the simmering. The boiling turbid wort is then run down into the tun, where, by this time, the goods are standing “dry” at 168° F.—the bright wort from them at that temperature having, as we showed, been run off and conveyed to the bright-wort copper. While the boiling turbid worts are being run down on to the goods, the rakes in the tun are kept revolving briskly, and the mixture of the goods and turbid worts should give 167° F. That temperature must not be overshot or you may get starch in your worts or beer. If any danger of exceeding 167° F. in the tun, then the last portions of turbid wort are cooled by adding to them a little cold liquor; or, in some cases, the whole volume of turbid wort is cooled beforehand to, say, 185—195° F., or whatever temperature may be necessary to obtain a mixture of 167° F. in the tun and no more. The rakes are now stopped, and the tun allowed to stand for 45—60 minutes. Please note again the position of affairs: On to goods very nearly but not quite exhausted of their diastase, boiled turbid wort containing liquefied starch (from the hard end of the malt) is brought down. The temperature of the goods parses, during that mixing, from 158° to 167° F., with a series of correspondingly dextriuous conversions. Dextrinous also will be the conversion of any starch that may have resisted in the tun during the infusion at 158° F., and which may now yield to the temperature of 167° F. With the boiling turbid wort we have also brought back on to goods at 168° F. nitrogenous matters that have been boiled—some of them have been coagulated and some extracted by the boiling. Whether, at 158′ F. in the tun, there is or there is not any sort of proteolytic action exerted on these nitrogenous matters I cannot say; the only thing certain is that conditions are totally different to those obtaining on the English system, where no boiling of matters such as those carried off from the tun in a turbid wort over takes place. To what extent the nitrogenous matter noted on during the successive treatments and conversions of the turbid wort contribute to the flavour, body and foaming capacity of the beers, it is equally difficult to say. But when you taste two beers mode from the same Belgian malt, one by mashing on the infusion system and one by the turbid-wort process, the difference is generally so marked as to convince you right away that, at all events for that particular malt, the advantages are on the side of the turbid method.
To return now to the mash-tun, which we left standing at 167° F. After, say 60 minutes, or time enough to allow the turbid wort to “saccharify” and clarify, taps are again sot and the bright wort pumped up to the bright-wort copper. The bright wort previously collected from the infusion at 158° F. may have been held in the copper at 100° F., so that its diastase may convert any traces of soluble starch that the now clarified but previously turbid wort may bring along with it. There is none, however, if you know your business.
The rest of the process is simply one of exhaustion of the goods by mashing-up again or sparging at temperatures (in the tun) gradually falling away from the maximum (107° F.) that had been reached, so as to avoid the danger of tardy liquefaction of any residual hard ends which would yield traces of starch to the worts; for, as you will readily understand, by this time the goods ore pretty destitute of diastase. With regard to mashing-up again versus sparging, to got a good extract it is generally necessary to mash up again, at least once, immediately after the clarification of the turbid wort, so as to rake back into the goods the thick coating of sludge that that wort has abandoned on the surface of the goods as it filtered through. Drainage is facilitated at these later phases by a liberal use of chaff.
The process, as I have now described it, may conveniently be summarised us follows:—
Such is the process in one of its simplest forms. In Belgium it has proved itself well adapted to brewing light beer, principally because it gives a full flavour. That full flavour is partly due no doubt to the fact that the worts are not subject to over-attenuation. Given normal Belgian malts and normal Belgian yeasts the bung-weight will vary from one-third to one-half the original gravity—generally one-third. Occasionally, with too friable or too easily saccharifiable a malt, or too attenuating a yeast, the bung-weight will drop to one-fourth original. Except for strong beers over 1040 sp. gr., the Belgian brewer considers one-fourth too low. But the attenuation depends, of course, a great deal on the malt and the malt on the barleys. With a winter six-rowed barley grown fairly quickly, say 8 to 10 days, kilned in 48 hours, attenuation, on the mashing process described, will not as a rule, exceed 66 per cent. Further, the process has the advantage of being elastic and adaptable. It is also delicate, and therefore attenuation can be controlled within fairly wide limits. I will give you two instances. The attenuation has been found to vary with the diameter of the perforations of the mash-tun plates. That may sound like a fairy tale; but it is easily explained. With the finest perforations, only the finest particles of malt flour, amounting almost to separated starch, will pass through the plates in the milky or turbid worts; and this finely divided starch will be converted, during heating up in the turbid-wort copper, at fairly low temperatures. With large perforations, on the contrary, larger pieces of grist, amounting perhaps to the smaller grits from the hard ends of the malt, will pass through the plates. These will resist conversion at low temperatures during the heating up of the turbid wort in the turbid-wort copper; but they will be gelatinised during the cooking of that wort and be returned to the tun in the- form of liquefied or gelatinised starch. But in the tun their conversion will take place at 167° F., thus increasing dextrin percentage and raising the bung-weight. It is also clear that, given some such temperatures as those set out in the above table, the worts can be made more or less dextrinous, and attenuation correspondingly influenced, according to the particular temperature or phase of the process at which, you elect to add, say flaked maize, to the tun or bring down into the tun a copper-full of raw grain previously gelatinised by boiling.
I should have liked to tell you something of what happens when English malts are mashed on the turbid-wort process, and of the necessary corrections that must be made, but time presses. There is, however, one point of immediate interest which may be dealt with. I refer to the influence of the process on the yeast.
Influence of the Process on the Pitching Yeast.
Practice has proved that “peptonisation” of the mash at 100—120° F., at any rate with Continental malts, undoubtedly tends to strengthen the yeast, whereas English mashing processes, with their high striking heats exerted on highly kilned malts, just as certainly tend to weaken it. In Belgium I never remember hearing of yeast weakness, at all events, in relation to low gravities. When one met with a poor outcrop, it was generally to be traced to an overdose of raw grain or to bacterial contamination of the worts on the coolers. Belgian worts of 1020—1040 produce at least 10 lb. of yeast (as collected in the troughs) per 100 1b. of malt. In many cases we often get half as much again, or, say, 50—56 lb. yeast per quarter. You can compare these figures with your own normal yields before the war. Now you have noticed that when you came to produce weaker beer i.e., to dilute your worts, your yeast suffered. There seems at first nothing to account for that, at least as far as nutrition goes. The total quantity of nutritive material is still there, though in a diluter form, and if it were a case of feeding animals, although the animal might be inconvenienced by dilution of its food, we should not expect it to suffer from lack of nourishment or in its reproductive capacities. Surely, therefore, if the weight of yeast collected has diminished per barrel of wort, the weight per quarter should remain the same. The fact that it has not always done so leads one to suspect that something also is going on, and that deficient outcrops will only be a passing phase. I fancy what may be happening is this: worts of a given concentration of malt and hop extract, producing a given concentration of alcohol, favour the growth of given types of yeast—say those that you have come to look upon as your normal English types. If you tamper with the concentration, you favour the growth of other types. Pitching yeast is composed of numbers of types, the normal variety or varieties being in great preponderance and so maintained as long as conditions favour them at the expense of other types. But alter the conditions, change the medium—and there is more change in dilution than might at first appear: acidity, total salts derived from the liquor, viscosity, number of cells per cubic centimeter, alcoholic concentration, all change—and, an a result of that change, other types of yeast, so far present perhaps in negligible quantities, so far crowded out by the normal yeasts that normal conditions have favoured, will multiply in their turn and gradually displace or crowd out the normal types. But this displacement of the original types of yeasts entails a change of flavour. As the crops increase, as the yeast seems to recover and gradually to adapt itself to the new conditions of weaker worts, the old yeast X or, which gave you the Y flavour that you required, is gradually being displaced by type Z, which happens to give C flavour, that neither you nor your customers admire. You know, for instance, that French and Belgian beers do not taste like English. The difference is partly due to the yeast. Once, many years ago, I pitched a Belgian wort with English yeast, thinking to give the customers a real treat. But they all complained; they did not want cyder, they wanted beer. Curiously, to the unaccustomed, the flavour of English beer recalls that of cyder. Similarly, since worts are becoming weaker, I have come across some English beers that remind one uncommonly of Belgian. Of course, as long as you mash English malts and brew on English methods, you will never get Belgian yeasts, but you will, by the dilution of your worts, perhaps eventually got yeasts approximating to the Belgian types. As a conclusion, if you wish to maintain the original flavor of your beers, you must pitch at each brewing a small tun of normal gravity worts, and secure your pitching yeast from that tun. Thus, you will stand a better chance of retaining both type and flavour. Although it is never safe to prophesy in brewing, I think it is within the bounds of possibility that mashing based on some such process as that I have described may even assist you to maintain your original type of yeast with worts perhaps slightly below the normal gravity, since they will be more nutritive worts than those you generally obtain on English lines. But that is, after all, only a supposition, and, meanwhile, it will be safer to keep up the gravity of the small tun of wort reserved for reproduction of the pitching yeast.
The Chairman said that they were extremely grateful to the Author for his paper. He had put before them many interesting details which he felt sure would be of great help to them, especially the latter, about yeast and yeast food. He asked Mr. Johnson, when he was using 50 per cent, of raw gram in his mash-tun, whether he used the raw grain converter at the same time? Also, if the beer having 66 per cent, of dextrinous matter in it remained bright, and if so, for how long? Was it fined at racking? Mr. Johnson had stated that the final gravities of the beers washed on the present system were lower than those obtained on the old system. Were the original gravities the same? Dealing with the question of yeast: Could Mr. Johnson tell them what constituted the chief yeast food in a weak wort? Did he use top or bottom yeast in his beers? What were the temperatures at which he pitched and at which the fermentations were carried on? How much yeast per barrel did he use for a beer of 1025°? Whilst discussing yeast production, one or two of his own experiences during the past few weeks might interest them. He had found that beers of different gravities, but having the same percentages of maltose and dextrin, and pitched with similar yeasts, gave the following results:—In quantity they all produced from four to five times the original amount used for pitching, but with this difference: In the case of the heaviest beer, 76 per cent, of the yeast was skimmed off, the remainder going to the bottom of the vessel. With a lower gravity, 40 per cent, was skimmed off, and 60 per cent, went to the bottom, whilst with a still weaker beer, 10 per cent, was skimmed off and 90 per cent, went to the bottom. Under the microscope, all the yeasts appeared to be clean and vigorous, and had since been used, in different proportions, with success. The beers racked clean and were similar in flavour, condition, and stability. Could Mr. Johnson explain why more yeast went to the bottom with the lower gravity beers? Would the specific gravity of the yeast influence it, in conjunction with the specific gravity of the beer, or would the small amount of CO2 in the weaker beers produce the results obtained? He hoped Mr. Johnson, with his large experience in brewing beer of low gravities, would be able to offer an explanation. He wished to thank Mr. Johnson for his very able paper, and he felt certain that the members of the Institute would appreciate the very clear and full details of the various systems of mashing which he had put before them. He was sure they would find them very useful in these days of low gravity beers.
Mr. D. Ward asked whether there was any sugar used in the beers in Belgium, and if so, what kind? Did they pay any attention to the water treatment, and were the beers supplied in cask for private family trade or put into bottle? How long did they generally keep in hot weather, as with the attenuation only to one-third, how did they stand transit in railway trucks on a hot summer day as compared with English beers? He was a country brewer, and had to produce beer for an agency business, largely by rail. Much as he liked the fulness produced, he was very anxious to know if they could safely brew on these Belgian lines, leaving the beers with so high a final attenuation. Would the beers keep sound on tap, and for how long, or produce a serious cask fret?
Mr. H. Brain asked whether the Author had any objection to oat husks in the mash-tun; he had mentioned the use of rice husks and wheat husks.
Mr. C. Chalders Thompson said he had brewed lager beer, and asked the Author if he could account for the yeast dropping to the bottom in a 20 lb. beer.
Mr. C. A. Finzel, referring to the Chairman’s remark that in brewing a low gravity beer he had got a large production of yeast, most of which went to the bottom, inquired whether he had found that this yeast under the microscope varied in type, and also whether, if it had varied in type, he had found it was any good for pitching.
Mr. H. F. E. Hulton said that the Author had told them that the Belgian brewer, having bolted his ground malt, then added rice or oat husk to his goods to secure good drainage. Ho would like to know what became of the malt husks, and if they were wasted, and why they could not be agaiu incorporated, and a saving thus effected in the use of outside materials. If he understood Mr. Johnson rightly, it appeared that it was to the obtaining of a dextrinous wort, due to high heats, that he attributed the palate-fulness of Belgian beers. Personally, he thought this was a fallacy, and that the most essential factor in palate-fulness was alcohol, and that the reason of the thin taste of most low gravity beers was to be found in their low alcohol percentage. If forced to brew at a low original gravity he would encourage the maximum production of alcohol of which the wort was capable, in order to mask the deficiency in extract. Coming to the question of X and Y yeasts, he was greatly interested in what the speaker had told them, and, whilst himself a disbeliever in the transmission of acquired characteristics, and, therefore, doubtful that pitching yeast, as a whole, was able to change its attenuative capacity when introduced into the new environment of lowered wort gravities, yet he would like to have further evidence of the alleged fact that in any given pitching yeast there were present all the time in small percentages other yeasts with different attenuative capacities which, by a change in the wort gravity, would thereby be favoured, and so become the dominant type at the expense of the originally preponderating variety. Unless this could be established, he thought the whole argument to be somewhat speculative.
Mr. J. Stenhouse said that, although, perhaps, the Belgian system when brought into England did not appear to be one they could adopt straight away, the description had been interesting and suggestive. He wished to ask the Author how long the Belgian mashing process would take as compared with the English process. Would it lengthen the brewing operations? He was rather inclined to agree with Mr. Hulton’s experience as to yeast, and, dealing with yeast, they were so very apt to get altered characteristics, that the question certainly appeared one well worth investigating, as to whether they were not getting another characteristic of one yeast rather than a selection of some other kind of yeast coming in.
Mr. Johnson, in reply, said that the Chairman had asked whether when raw grain was mixed in with the malt in the mash-tun they also used a raw grain copper. They did not. When raw grain was mixed in with the malt no separate raw grain vessel was necessary. Whether the raw grain were rice or wheat or very finely ground maize flour, it could be dealt with in the mash-tun. The practice was no longer very common. There was one absolutely essential condition, and that was that the flour should be very fine, and well mixed in. They could not, for instance, deal with maize grits in that way. The Chairman had next asked whether, when the Belgian brewers in 1885 changed their system of brewing to adapt it to the new law, they changed the original gravities of the beer. They did not. They kept to the original gravities, but it was the final gravities that fell as the result of the change in the composition of the worts. He had not given any figures for percentages of dextrin. What he had said was that tome of the beers attenuated 75 per cent., others 66, and others only 50 per cent. He had avoided any analytical figures because, for one thing, he could not trust his memory, and because those figures would vary from brewery to brewery, and especially with the materials used, for the same reason the question of the composition of the worts considered as yeast-food was very difficult to answer. He thought he ought to add that everything he had said applied exclusively to top-fermentation beers. He had not touched on the question of bottom fermentation beers. The Chairman had next asked at what temperature they pitched their top-fermentation beers. They pitched fairly high—68 or 69° F. in winter. The casks in which they fermented the beer wore small; beer was not fermented in tuns as in England. The volume being small, the pitching temperature must be high; otherwise, if the cellar were cold, the temperature might drop, and there would be no fermentation or the yeast might go to the bottom. With regard to the weight of pitching yeast per barrel, they used a kilo, to a kilo and a half of pressed yeast for 100 kilos, of malt; that was from 1 to 1½ per cent, of pressed yeast calculated on the weight of malt, or say, at the lower percentage, roughly, 5 lb. of liquid yeast to a quarter of malt, or 1 lb. of liquid yeast to a barrel of 18 lb. beer. The Belgian yeast was so prolific and reproduced at such pace that the weight of pitching yeast did not appear to matter within wide limits. He had tried all sorts of quantities of yeast from very small to very large, but it made no difference on the ultimate yield. The total outcrop remained more or less constant, and depended upon the total amount of fermentable and nutritive material in the worts, and not upon the weight of pitching yeast used. The Chairman, however, was specific in his question. He asked, when a 1025 beer was brewed how much yeast was used. They did not calculate the amount of yeast on the gravity of the wort but on the weight of the materials. The Chairman originally gathered from his worts five times as much yeast as he pitched; and he had still fire times as much, but now unfortunately some of it went to the bottom. He could not say why that was. The yeast had been upset by the new conditions. Yeast came to the top by the action of the escaping CO2 not only on individual cells but on entanglements, and there were other physical influences which, had nothing to do with its general properties as a ferment. If, for instance, they fermented Belgian wort with an English yeast in cask, no yeast came out at the top at all; it all went to the bottom. Whereas, if they pitched with a Belgian yeast in casks, the first white head began to work out of the bunghole within an hour or so. There was evidently a difference between the two yeasts. Perhaps at the start the Belgian yeast did not require so much aeration as the English. He thought it could be safely said that whenever conditions in any way interfered with the normal behaviour of their yeast, one of the first symptoms was the presence of a lot of yeasty sludge on the bottom of the fermenting vessels. In Belgium they did occasionally meet with the accident of all the yeast going to the bottom. That accident generally arose from contamination of the worts on the coolers, and happened especially in breweries where the worts were exposed too long in those vessels. The consequence was that by the time the worts were run into the fermenting casks they were already contaminated, and there was competition between the bacteria and the yeast, in which the yeast was sometimes worsted and went to the bottom. Mr. Brain had asked whether there was any objection to using oat husks. There was none. Perhaps the only objection was that they were as a rule dirty and more difficult to wash than rice chaff and wheat chaff. Before they used the chaff they washed it. Oat chaff would do, and rye especially did well, but rice husks were the best owing to their rigid texture which presented the tendency to collapse or flatten out. It seemed to be a physical value entirely. He believed that in England they used to chop up straw. In Belgium ho had never seen that. In the old days, when they got a set mash, they added a bushel or so of malt flour. Mr. Thompson had also met with the accident where, even in a 20-lb. beer, the yeast went to the bottom. That was not an infrequent occurrence. He had known yeast go to the bottom when too much raw grain had been used; but it was also liable to go to the bottom if the temperature was too low, or if the temperature fell directly after pitching; and it went to the bottom particularly if the wort got contaminated on the coolers. It must be remembered that all yeast-cells, unless gas were being evolved, naturally would go to the bottom. When yeast was stirred up in a tumbler of liquid, if there were no fermentation, to the bottom it went. Anything, therefore, that tended to interfere with or prevent fermentation would also tend to send the yeast to the bottom. Even with a boiling fermentation the yeast failed to come to the surface. Entanglement, for some reason or other, perhaps connected with budding, was suspended; but he did not know the reason. The next question was whether a top yeast that had gone to the bottom was good for pitching. He did not know, but he would not use it himself if he could get any other. It might revive and recover its properties of coming to the surface; but there was evidently something wrong with it, and it was a safe rule in brewing never to use for pitching a yeast that had shown any undesirable peculiarity. Mr. Hulton wished to know why they went outside for their bolted husks, and why they did not put the malt husks back. One reason was because on the old system of mashing they used to grind extremely fine so as to got more in the tun. With that system the raw wheat and barley malt were ground together between stone mills, and the husks were reduced to what they called “needles” or spikelets, and however much they put those husks back—and ns a matter of fact they did put them back—they still wanted the broad wheat chaff to got a filtration. If they had had modern mills as now and obtained the malt husk practically unbroken, it would perhaps have done as well as anything else. Mr. Hulton thought that he (the Author) had rather overdone the influence of dextrin on body or palate-fulness of the beer. They would have read lately in the brewing journals that Windisch had come to the conclusion that the best way of giving body to a very light war beer was to convert completely and produce alcohol rather than dextrin. It was a very interesting question; but for high beers, at any rate, Belgian practice seemed opposed to Windisch’s views. Nor had Belgian beers ever been so light as those Windisch was considering. There were probably present in the wort produced on the Belgian system a lot of undetermined gummy and glutinous substances, which had an effect on palate-fulness. He was not prepared absolutely to say that the beers were fuller just because they were more dextrinous, but he thought it was safe to say that dextrin had something to do with it. Beyond that, were there not the intermediate carbohydrates, which besides giving body themselves, tended to keep other body-giving substances in solution? It was a question for the chemists to solve, and he felt certain that Mr. Hulton knew a great deal more about the analytical aspects of the problem than he did. Mr. Hulton also asked his reasons for believing in displacement of yeast types and not a change of characteristics in the original yeast. All experience seemed against the probability of any alteration in the character of a yeast in the course of any number of brewings or perhaps elsewhere. Large numbers of Belgian brewery yeasts had been analysed by Yan Laer, and ho found that variations in their behaviour in the brewery were often referable to some disturbance of the normal ratio of one type to another. They would remember the case of Vnn Laor’s composite Burton yeasts, artificially remixed because a primary yeast could not be induced to acquire the habits of a secondary. In practice, owing to inevitable contamination, it was doubtful whether there ever was such n thing as a pure yeast in a top-fermentation brewery. There must therefore be competition between the types. But there were other reasons for believing in displacement. In breweries where pure yeast was used, the practice now was to odd a certain proportion only of fresh pure yeast at every brewing, or every few brewings, so as to maintain the preponderance of the desirable type. When brewing weaker beers he thought it would be wise, if they did not wish to change the character of their beers, to take precautions against the risk of displacement. Mr. Ward had asked whether they used sugar. They used plenty of glucose and invert. Glucose was much in favour, because Belgian glucoses were dextrinous. Invert sugars had a tendency to give them thin light beers. For stronger beers invert was used because then the attenuation did not so much matter.
Mr. Hulton said that the Belgian glucoses were not what they understood as glucose in this country.
Mr. Johnson agreed.
Mr. Hulton said that glucose, as used by an English brewer, contained practically no dextrin. It contained dextrose and a little maltose.
Mr. Johnson, continuing, said that the Belgian glucose makers attached importance to the presence of “unfermentable” matter. With regard to the question as to how long Belgian beers would keep, it was an extraordinary thing, and they might think it was not possible, but weak beers kept better than strong. He had noticed it over and over again. If, in the same brewery, they made a parti-gyle, dividing it into 1050 and 1030, the 1030 kept best. He did not know why, but it was so. He referred, of course, only to Belgian beers. As a matter of fact, however, all the beers he had been speaking about were running been, and were consumed quickly. As a rule, the brewery supplied only a given radius; very little of the beer was sent by rail. When it was a question of transit, they brewed lager beer, so that he was unable to say how the beers would stand the journey, because they only sent strong beers or lager beers by rail. If a beer was not fermented out, there was a tendency to fret, but inasmuch as the wort was fairly unfermentable, the fermentation was finished. That was to say, the yeast had carried the attenuation as far as it could in that given beer. They were not dealing with a fermentable wort of which the fermentation had been stopped before it was complete; but with a wort so prepared that the fermentation would only go a certain way. Their greatest enemy, perhaps, was wild yeast. Wild yeasts grow readily in some of the beers. They bottled the beers, in fact, in big towns where the tendency was more and more toward a bottle trade. The beers were chilled, filtered and bottled, and they would stand for a fortnight at least in the summer and six weeks in the winter, according to the beer and according to the chilling. They had to be careful in choosing their materials for beers for bottling and chilling. For instance, a beer made from Algerian barley would stand better than that made from a Belgian spring barley. After all, it was mainly the materials that determined the nature and properties of a beer.
A hearty vote of thanks was passed to the Author.