A Study on Extracts Part II

MEETING HELD AT MIDLAND HOTEL, MANCHESTER, ON FRIDAY, MAY 4th, 1906.
Mr. A. L. Lees in the Chair.

The following paper was read and discussed:—

A Study on Extracts. Part II,
by W. Stanley Smith, Ph.D., etc.

It is just three months ago that I had the pleasure of reading the first portion of this study on extracts, and I propose to continue the subject, and to develop this theme upon the same practical and familiar lines as I did in the paper read before the Scottish section of the Institute of  Brewing. Perhaps I had better state at once that I have no very drastic measures of reform to bring before you; my intention is solely to urge upon my fellow-craftsmen the necessity formaking the most of the appliances and machinery which engineers have designed to assist in the brewing of beer. In fact, our entire attention will be directed, as far as possible, to essentially practical affairs, as they present themselves in a modern brewhouse.

The question of extract has assumed such an important position in our industrial economics within the past decade or two, that it must appeal to every brewer who has competition to face and dividends to pay. In the old days, when the product of a “publick brewhouse” was reckoned far inferior to that concocted in the private cellar or tavern kitchen, this question of malt yield did not so largely loom on the business horizon. Indeed, in the light of latter-day experience I have not the least doubt that a very considerable percentage of the available contents of the malt-corn was formerly left unexhausted in the mash-tun. I do not see how it was possible to regulate and control the extracts obtained from various malts, and at different brewings, until that day had arrived when the use of saccharometers and thermometers had become general. It is very curious to reflect that scarcely more than a century ago the whole art of brewing was wrapped in a cloud of mystic empiricism, and yet the laws respecting the comparative specific gravity of fluids and solid bodies immersed in them were discovered by Archimedes nearly 2200 years ago. The hydrometer, called in early Latin hydrometrum, hygroscopium, hygrobaroscopium, hydroscqpiuniy areometntm and baryllion, is founded upon that classic experiment with Hiero’s golden crown, and the instrument which serves us to determine the weight or specific gravity of different fluid masses, by the depth to which it sinks in them, was first mentioned so long ago as the fifth century, in a letter sent by Synesius to the learned, beautiful and chaste Hypatia. In his fifteenth letter, Synesius tells Hypatia that he found himself out of health, and as he wished to use a hydroscopium—for a purpose we may perhaps, correctly surmise—ho requested his fair friend to cause one to be constructed for him. “It is a cylindrical tube,” says he, “of the size of a reed or pipe. A line is drawn upon it lengthwise, which is intersected by others, and these point out the weight of water. At the end of the tube is a cone, the base of which is. joined to that of the tube, so that they have both only one base. This part of the instrument is called baryllion. If it be placed in water, it remains in a perpendicular direction, so that one can discover by it the weight of the fluid. “It is thus clear that the saccharometer of to-day is closely akin in form to that of the fifth century, and yet it was only in the year 1768 that an instrument of this type began to be used in the  brewhouse. This highly important event happened at Alloa, N.B., where old Mr. Baverstock had a brewery of his own. Describing the circumstance in his Treatises on Brewing, Baverstock says, “in 1768, an hydrometer was used with the thermometer by the writer, in his own brewery in the country. This was so unthought of at the time, that even the maker of the instrument, Mr. Martin, of Fleet Street, was with great difficulty persuaded that it could be made useful in the brewery.” It appears that the same incredulity prevailed among some of the largest brewers in London, to whom the matter was communicated in 1770, but it is certain that ten years after this date both hydrometers and thermometers became more generally used.

The introduction of these instruments first made it possible for brewers to consider their mash-tuns from the extract point of view. Strange to say, we owe it to one of George II’s physicians, a certain Dr. Shaw, that the thermometer forms part and parcel of our plant. It was from the learned medico’s Chemical Lectures and Essays, that Mr. Michael Combrune took the hint to introduce a thermometer into his brewery, and about the year 1760 he published his post-quarto volume on the subject, which he inscribed to Dr. Shaw. A contemporary writer furnishes us with the laconic comment that “neither the publication nor the instrument were much attended to by the brewers of that time.” This attitude of apathy is, however, in this isolated instance, scarcely to be wondered at, as a study of contemporary brewing literature reveals to us the entertaining fact that, by more than one writer, the part played by thermometry is somewhat ludicrously exaggerated that it was clearly not feasible to found a system of brewing on the thermometer alone, appears to have been so very patent to our practical and hard-headed forefathers that possibly the pretentions of some too enthusiastic parties tended to prejudice those eminently conservative craftsmen against an instrument without whose aid they had battled, with more or less success, throughout the long years of their experience. Suffice it a strenuous century and a half has flown by since those years of technical blindness, and we are, nowadays, so well equipped with instruments of precision, that the systematic study of extracts has become a daily habit with every honest and capable brewer.

It is not my intention, upon this occasion, to infringe upon the business of the chemist. I have considered the question of extract solely from the point of view presented by the physical and mechanical conditions with which our mash-tuns are surrounded, I feel that time can well be spent in more detailed study of some of the practical items of our routine procedure. This routine consists of three distinct operations, namely, grinding, mashing and sparging; and the enormous extent to which extract can be controlled by these three factors must be experienced to be believed. In the first part of this paper, that which I read at Edinburgh at the end of January, I attempted to thoroughly analyse the effects of the first two named factors, the grinding and the mashing. The deduction I had gathered from a long series of experiments in the brewery, is simply this: Other things being equal, the whole secret of high extract is centered in fine grinding. I venture to entertain the hope that you will read my previous paper in conjunction with the present one, so that the train of reasoning and experiment which has led me to this conclusion may be followed link by link, and that what I have already said may be taken as qualifying what I have now to say.

There is always something of interest and value to be found in the writings of those old craftsmen whose active labours have long since ceased. The old authorities, such as Richardson, Combrune, Shannon, Morrice, and Accum, to name but a few with strict impartiality, always appear to me to have possessed a practical and familiar acquaintanceship with their surroundings, and whilst one is forced to admit there is in their writings a vast surcharge of quaint, useless, pompous, and pretentious verbiage, yet the pearls of wisdom, diffusely scattered though they be, are pearls even unto this day. In order to give point to our moral, let us take this very subject of grinding. It is evident, from several erstwhile justly-esteemed authorities, that the whole matter resolved itself into terms of mash-tun drainage. The earlier writers, with one or two notable exceptions, give one the impression that their allegiance to coarse grist is founded on common sense and expediency, in fact, on conditions of plant and appliance as available in their own time. It is evident, however, that the narrow confines of technical science a century ago are not the boundaries which should hem in our present procedure. The limit imposed upon the set of malt rolls was, as I have said, strictly defined by questions of buoyancy in the mash-tun, and whilst many of the brewers who lived and worked in a former generation were well aware that, in the words of W. H. Roberts, the author of the Scottish Ale Brewery published in 1847, “the more finely the malt is ground the more readily will the liquor penetrate, and consequently we shall obtain a better extract,” yet the majority of those early craftsmen, his contemporaries, appear to have recognised that the one insuperable objection to this system of fine grist lay in the danger of the “goods” setting, and thus causing the defeat of the very object for which their whole procedure was designed.

I have pointed out the fact that this danger no longer exists. It is, nowadays, not only possible, but easily possible, to successfully brew from the finest of grist. Provided intelligence and care be expended on the process, we have in modern mills, modern mash-tuns, and, more particularly, in modern spargers, every conceivable appliance which is necessary, or which can under ordinary circumstances be required, for obtaining an efficient extract. The details of mill-work you will find in my other paper, and I have also embodied in tabular form a series of tests intended to illustrate the very intimate relations existing between grinding and extract.

The process of mashing is a detail so important when fine grist is employed, that we can no longer afford to regard it as a function of the stage foreman. Under the old conditions of coarse grinding—conditions which I firmly believe are destined to speedy dissolution—it certainly did not much concern the brewer whether his grist was roughly or gently handled. But fine grinding emphatically demands careful mashing ; indeed, every detail of what takes place both outside and inside the mash-tun demands forethought and attention. I am speaking now from 12 months’ experience of grist as finely ground as possible in a modern, fully-equipped malt mill. During this period I have learnt many lessons, chiefly from the failures which at first attended my efforts. The initial weeks of fine grist linger in memory as a period of flood and disaster. I have no hesitation in saying that extracts were not satisfactory at this experimental stage in the art of fine grinding; but a systematic study of mashing machines, mash-tun areas, rakes, and, most important of all in many respects, spargers, has resulted in a measure of success which amply repays for its tardy arrival. The measure of this success I can best convey to you by quoting these following figures. In using a grist composed of 43 per cent English malt, 15 per cent Californian, 17 per cent, flaked maize, and 25 per cent, inverted cane sugar, I have found the average extract obtained with fine grist, and what I may be permitted to term scientific sparging, to be 3*3 per cent, higher than under the old conditions of coarse grist and clumsy sparging. In other words, the former average of 881b. per quarter now stands at 91 lb. per quarter on total grist.

I will now turn your attention to some of the facts and figures connected with the art of sparging. Even as was the case with the saccharometer, so it is with this beneficial appliance designed for sparging—we owe its introduction to the Scottish brewers. Sparge arms shared the fate of every great reform, and it was many long years before the English brewmasters could be induced to abandon their old system of draining off the worts from their tuns and then mashing up. A short quotation from Mr. Richardson’s Treatise on Brewing, published in 1804, will serve to illustrate the prejudice against which this innovation of sparge arms had to battle. “By the use of the saccharometer” says he, “we are enabled to detect that absurdity in the practice of many country brewers, which the notable dames of yore agreed to call leaking on, a term which means nothing more than the continued sprinkling of water upon the malt, after the tap is nearly spent, till the quantity of wort is produced which the brewer thinks will yield the required length or quantity of beer without any regard to the quality of the malt or that of the wort so produced. The least reflection . . . will point out the absurdity, though reflection alone will not inform us how much is lost by the practice; for what power or what time has a fluid to extract which is sprinkled over the surface of the materials and immediately trickles out below, without being allowed a stationary moment for infusion? And, though the practice I am here condemning,” says Mr. Richardson, “is confined to some small breweries in the country, I cannot exempt the larger ones from all share of censure on the occasion, for if the piece liquor of some of them be not exactly in that predicament, it verges so nearly upon it that I cannot pass it over without recommending the subject to the consideration of the proprietors. “Such are the “scientific Mr. Richardson’s” views of sparging, and there is no doubt of his standpoint, or of the misguided train of reasoning which led him to the views he so trenchantly expresses. “He was led to form so unfavourable an opinion,” says an able practical brewer of 1847,” by want of due consideration; or, being prejudiced against it (sparging), he has not put it to the test of experiment.”

The attitude assumed towards sparging was, strange as it may seem to us, pregnant with that spirit of caution and suspicion formerly so typical of the English brewer, but that by the time Queen Victoria had ascended the throne some progress had been achieved, is obvious from the remarks made in Mr. William Black’s book, issued in the year 1855. The author confesses his work a maiden literary effort, and he ventures to apologise for “the homeliness of his style.” Nevertheless, the remarks Mr. Black makes about sparge liquor display a wise caution, and in many respects ring singularly true unto this day. “Many of our best brewers,” says he, “have now adopted sprinkling or sparging, or, in other words, draining liquor through the mashed goods in preference to mashing again. This mode of working has certainly many advantages to recommend it. In the first place, it saves labour; in the next place, when we wish to make very strong beers, either ale or stout, we can more easily throw in the desired gravity by sprinkling than mashing. I should, therefore, on all occasions of brewing very strong beers, resort to sprinkling.” It is evident to us that even as grinding was controlled by considerations of mash-tun buoyancy, so was sparging limited by considerations of beer gravity. Nothing could better illustrate the innate caution, the in-born suspicion of change, which has ever characterised nearly every British industry. When beer of not more than 24 1b. gravity is brewed, with a raw wort to follow, the brewer of 70 years ago was advised that “it matters little which mode is adopted.” i.e., whether he sparged or relied solely on the mash-up, to obtain the available extract; but in cases where there was no raw wort in question, it was definitely decided that “sprinkling will always be found most advantageous.” The connection between raw wort and sparging was deemed an intimate one in these pioneer days. One well-known London brewer of the early forties, Levesque by name, regards “fly-mashing, which,” he says, ” is modernly termed sparging,” as decidedly beneficial, as tending to do away with raw worts. His argument is interesting, and has the merit of being refreshingly original. Says he, “in this method of fly-mashing, the after liquors pass through every interstice of the goods; by which method, concentrating the strength, saving valuable time, and helping return worts, as they contain nothing but the worst quality and are by no means desirable. It may seem extravagant to throw away a return wort, the gravity of which is 5 or 6 lb. per barrel; it is, however, like skimmed milk, but of little value.”

The varying procedure of that day may best be summarised as follows:—Some preferred to run off the first wort before they began to sparge; others, having thoroughly mashed with 1½  barrels per quarter, immediately started sprinkling at temperatures between 190° and 200° F. This, be it said, was done very slowly, and the liquor was made, by means of a now very familiar apparatus for the purpose, to descend like rain over the top of the goods. Again, many brewers deemed it expedient to run on sparge liquor to the extent of half a barrel per quarter, before setting taps, and however incorrect many of Black’s conclusions may have been, he appears to have grasped the importance of that half-hour’s interval which elapses between the finish of mashing and the turning under of piece liquor. He tells us that his study of sparging leads him to the conclusion that this process goes very far to prove what he had repeatedly stated, namely, that the whole extract is made by the first mash, and that the subsequent mashes merely wash out that extract. “By means of either a dipping rod,” says he, “or any mark in the mash-tun, you can regulate your running on and off in equal quantities during the process.”

The question of wet dip appeared to me at one stage of my experiments of perhaps more importance than it really is. I have already given my opinions on the subject in the first part of this paper, and I will venture to once again call attention to the essential conditions that prevail in the mash-tun during the period of running off the worts into the coppers. From the first moment of setting taps a gradual decrease in the volume of malt contents is set afoot, and the lowering of the wet dip of the goods does not necessarily mean we have much less water in the tun. I think the object we should aim at is the maintenance of a fairly constant ratio of liquor to malt material, so that the relative proportions of each are kept as uniform as possible throughout the process of extraction. Of course, I do not wish this suggestion to be taken in any arbitrary sense, but rather that it should embody the larger suggestion, that a definite and regular rate should be cultivated in the fall of the goods. I have not concealed from you the fact that when I first started the use of finely ground grist I met with a good deal of discouragoment, which was chiefly due to sparging difficulties. I am equally free to confess that it was mainly owing to the assistance and advice of my friend, Mr. W. P. Harris, that these difficulties were finally overcome. There is no practical brewer in this country who has made such an extended and intelligent study of the theory of sparge appliances as Mr. Harris, and if the fine-grist system, which I have found so successful, be generally adopted, I feel it is largely owing to him that brewers will have made this stride. However, I am not authorised to speak on his behalf, so I shall confine myself to the relation of my personal experience and my personal views on the question of sparging.

Nothing is more common, or more stupid, than to take the actual for the possible, or to believe that all which is, is all which can be—first to laugh at every proposed deviation from practice as impossible, then, when it is carried into effect, to be astonished that it did not take place before. If it had been proposed to submit our malt to as fine a grinding as the mills were capable of effecting some few years ago, a rolling wave of incredulity would have greeted the suggestion. And yet, it has long been known that in laboratory analyses, conducted for the purpose of estimating the available extract of any given sample of malt, the material was invariably reduced to a fine grist. The reason why the logic of this point was not pressed home to its legitimate end is simply and solely concerned with the fact that such grists have, until within quite recent times, proved remarkably unmanageable in the mash-tun. The difficulties of extraction, the dangers of flooding and setting, have nullified all efforts made to obtain increased extract by means of finer grist. And yet we must know that if a laboratory experiment proves a certain malt to contain a certain amount of extract, there should be no theoretical reason why this extract should not be yielded up from the mash-tun. It was, and in most cases now is, from purely practical considerations that brewers favoured a coarser grist—a type of grist which reached its uttermost development by the use of the fluted rolls we remember 20 years ago. But the physical secret of a buoyant tun of goods is revealed; and if brewers will make a careful study of their sparging apparatus, directing every factor in the construction of this important piece of machinery towards the needs of a floury grist, there will soon be an end to all those difficulties of drainage which centuries of practice have associated with closely milled grain.

The first question which suggests itself in a systematic study of sparging lies closely connected with the laws of moving liquids. Some knowledge of these laws is necessary to the brewer who would secure uniformity of result in the produce of his mash-tun. As I have previously suggested, it is an important point to secure the onflow of liquor over goods at definite rates and in definite quantities; and, although one cannot pretend to any comprehensive figures on this subject, yet one can at least urge the plea of systematic method. Let it then be granted that the pipes or conduits which are intended to supply sparge arms must be so cast as to permit a given flow in a certain time. With the problems centred in intermittent supplies we will not concern ourselves. Now the quantity of liquor which finds its way through any orifice will depend, in large measure, upon the force employed to drive it through. This force is a quantity easily ascertained, and it is generally known as “head.” But besides this factor we have also to reckon with the nature and form of the orifice, as it is found in practical life that an orifice, for instance,

in a thin plate will give different quantities to that supplied by a short tube; and the latter, again, differs in actual discharge from a long tube. This fact is familiar to every analytical chemist, as even in the simple operation of decanting a liquid through a funnel in the laboratory some attention must be paid to the duct by which the fluid escapes, and the brewer can easily convince himself by experiment of the practical effect of lengthening the fall tube of the funnel, or of increasing the horizontal outflow pipe from a tank or jar. In the latter case an important lesson is taught, for it will be discerned that the longer the pipe, the less liquor will flow through it in a given time, under the same force or head, so that to maintain the same flow through a long pipe as through a short one, the pressure must be increased.

It will thus be perceived that by no means an unimportant factor is the maintenance of sufficient pressure, in order to ensure uniformity of flow and speed in the sparge arms; and, for this reason, I will devote a few moments to this topic. The “head” in feet may be readily converted into pounds per square inch. In rough and ready calculations, one often assumes that the head of water in feet is double the number of pounds per square inch pressure. This rule, however, is only approximate, and as the exact figures are easy of calculation, we might as well accustom ourselves to accuracy. Each foot of water corresponds to 0*4327 lb. per square inch, and in the following table I have given the equivalent pressure for depth of head, up to 9 ft.:—

The next consideration we have to deal with is the actual quantity of liquor which will flow through a pipe, and this is a matter so easily calculated by the use of a well-known formula, that all I will do is to append this formula, for the use of brewers in their practical operations:

Hawkesley’s formula for the flow of liquor through pipes, where—

There are usually so few bends in brewery sparger mains, that we may neglect the data for the head necessary to overcome the friction they cause, but whilst we desire to avoid all unnecessary finesse it is expedient to draw attention to the head required to overcome friction where water, or any other equally mobile liquid, is concerned. This may be approximately calculated from the following formula :—

As an illustration of the usefulness of this formula for calculating the head necessary for overcoming friction, I cannot do better than cite the following instance: We may suppose that it is desired to pass 1200 gallons per hour through a pipe 100 feet in length, from one tank to another, situated at a lower level. The formula tells us that if the pipe be 1 inch in diameter, a head of 54 feet will be necessary, but if a 3-inch pipe be employed, the head necessary to overcome friction is but 0*33 foot of water. (Davis, A Handbook of Chemical Engineering, p. 347.)

Finally, in connection with the flow of water through pipes, it should be borne in mind that these theoretical calculations refer to new, or thoroughly clean, mains only. The effects of corrosion or of deposits upon the interior surface of pipes are sufficiently serious to demand special attention, as any incrustation upon the internal surface of a pipe will not only decrease the delivery capacity, by reason of constricted area, but it will also increase the friction to a great and often remarkably troublesome extent.

It is time we pass rapidly on, but before leaving the subject of pipes, it might be well to remind the junior members of our profession of the relation of the area and the cubical contents of any figure to the linear dimensions of that figure. The head and length of pipes being constant, the supply varies as the square root of the fifth power of diameter, or as d 5/2. It is said that at an examination of candidates for the position of fireman in one of our largest establishments, several of the applicants made the mistake of supposing that a 2-inch pipe and a 5-inch pipe were equal to a 7-inch pipe, whereas the combined capacities of the two smaller pipes are to the capacity of the large one as 29—49. The story told by Sir Frederick Bramwell, the engineer, will illustrate how easily one may make a mistake in this matter of outflow. A certain water company required more liquor, and after negotiations with the owner of the stream, offered double the sum originally paid if they were allowed to take their supply through a pipe of double the diameter of the one then in use. This was accepted by the owner, who evidently was not aware of the fact that a pipe of double the diameter would carry four times the supply! Concisely expressed the rule is as follows: A square whose side is twice the length of another, and a circle whose diameter is twice that of another, will each have an area four times that of the original.

In using sparge arms over a mash-tun containing finely ground malt, we must remember that the main object to be studied in their construction is the prevention of heavy masses of liquor descending on the grist. It is because we should learn how to atomise the liquor that I have dealt at some length on the subject of head and pressure. The finer the spray, the less liability will there be of flooding our goods, and when we call to mind how prevalent is this inconvenient phenomenon even in the case of coarsely-ground grain, it will be doubly obvious how carefully designed the sparging plant must be in order to fulfil the conditions in demand. These are, of course, adequate regulation of liquor quantities, and the uniform distribution of such in the manner best calculated to avoid mash-tun disturbance. The most beneficial method of apportioning liquor quantities is, necessarily, best found out by direct experiment. Each brewer has different plant to deal with; his mash-tuns vary in dimensions, his sparge arms follow suit, and it is only by direct experiment that these quantitative factors can be regulated. I have, however, thought it worthwhile to furnish a guide in these matters, and have accordingly drawn up a table in which is shown the amount of liquor passed through sparge arms of varying lengths, with varying numbers of holes each sized to 0*032 inch, and travelling round at varying rates, under varying pressure heads. It seems clear to me that the brewer should know exactly and accurately the capacities of his sparge plant, and no better method of gaining this knowledge occurs to me than by constructing tables, from actual observation, of what takes place under given circumstances such as are represented by the number of holes, average head, and frequency of revolution, the arms are caused to make at the instance of the forces which play upon them.

In the ordinary type of sparge arm the holes are far too large, and whilst they revolve at a comparatively slow rate, they at the same time permit of a heavy and constant stream of liquor playing upon the goods. It is the business of those who adopt the fine-grinding system to alter all this, for nothing short of excessive flooding follows upon the use of old-fashioned, slow-running

and large-holed sparge arms. I know that very skilful adjustment of the time taken to run off the first copper will) to some extent, minimise the evil, but for all that, my main contention holds good. In the ideal apparatus for sparging, or “leaking-on,” as our forefathers called it, those “wires” of liquor are split up, cohesion is destroyed and the mass of water to a large extent atomised. Instead of descending in slow and solid streams, it is absolutely necessary to discharge the liquor in such a manner that it alights on the goods in almost imponderable drops, and it is precisely because this indispensable condition was satisfied that I adopted the ingenious device associated with the names of Harris and Guest. The arms are separately connected up with the liquor tank, the holes are exceedingly small and the velocity attained under suitable pressure is such that one can scarcely see the arms as they fly round. And equally important is it to note, the holes are so placed, as the result of mathematical calculation, as to allow for the ever widening area each portion of the arms has to travel over, as it nears the circumference of the mash-tun. Given these perfections of design, the remaining question resolves itself into how best to use the spargers.

For a long time I had been somewhat disconcerted by the fact that extracts were by no means so regular as one likes to see them, when varying quantities of grist wore mashed. The results of brewings in which the same amount of grist was used always came out fairly uniformly, and, in consequence, it seemed to mo evident that there existed an ideal depth of goods at which to work. This, in fact, from the uniformity and quantity of extract resulting therefrom, proved to be the case, and I must say it struck me as a weak spot in the fine-grinding system of working. We know that in the daily procedure of brewhouse affairs we have to deal with grists that may vary in amount to a very considerable degree: in other words, although an ideal depth of goods for a certain mash-tun may, and undoubtedly does, exist, under given conditions, yet the brewer is not always in a position to conjure up those special conditions. It is independence of action that seemed to me necessary for perfection, and during the last three or four months I have, I think, secured freedom from any conditions which restrict the thorough extraction of malt contents to stated mashtun factors, such as wet dip and the like. This has been achieved by the simple device of having two sets of sparge arms, one of which discharges double the quantity of liquor in a given time, as compared with the second set. Now in the brewhouse where these trials were made, it is customary to draw off the worts into two or three coppers. The first copper is made up very slowly, using the sparge arms which only discharge, say, for comparison’s sake, half a barrel of liquor per minute. After gentle raking, and 30 minutes’ stand, we make up the second copper in exactly half the time per barrel that was occupied in the case of the first copper, using for this purpose a set of sparge arms which discharge exactly double the amount of liquor (say one barrel per minute) than was the case with the arms used for our first copper. This applies to the brewing of all beers of ordinary normal gravity, and when beers of the rare old Yorkshire Stingo type are in course of manufacture, the two coppers are both made up at the slow rate, using the spargers which discharge the lesser amount of liquor. This method, you will observe, is capable of indefinite modification, and when carefully carried out the net result is that inequalities of extract tend, to a great extent, to disappear. I now expect to see a reasonably regular return for all lengths, brewed from like materials.

The adoption of fine grinding and a carefully arranged system of sparging is followed by n considerable gain in extract. The actual mean increment of extract on total grist, in my own case, works out at something over 3 per cent., and, as compared with laboratory extracts, it comes within 1 or 2 per cent, of the figures obtained by the analyst. In fact, the finer the malt is ground, the more nearly does it yield in the brewery the extract obtained on analysis. This result has been made possible to a considerable extent by careful study of such generally neglected factors as the uniform distribution of definite quantities of sparge liquor, in such manner that the goods are not called upon to bear any appreciable weight of liquor at any time, and it has enabled one to regard the malt mill in the light of a machine so designed as to crush the grist as finely as possible. The only consideration remaining for attention is concerned with the quality of the beers brewed under the conditions I have mentioned. Briefly stated, this quality is excellent; it leaves little or nothing to be desired. I have, however, noticed all through my experiments that the attenuations did not reach so low a point under the new conditions. At first this circumstance naturally aroused a sense of uneasiness as to what would be the behaviour of the beer in the trade. But the experience of an entire summer, indeed, a whole cycle of the seasons, convinces me that there need be no anxiety on the score of unstable and less readily fermentable matter being left in the ale after true primary fermentation. Another test is the healthy appearance and enhanced vigour of the yeast. There has been no change of barm in the brewery where most of these observations were carried out for at least 11 years past, and to-day the yeast is, if anything, better and more uniform in type than it ever was.

There is no tradition among us so lacking in general soundness as that which declares the stability of beer to be essentially controlled by high attenuation. That this is a very loose proposition must be evident to every brewer who has mastered the rudimentary science of the craft, for, as was so clearly pointed out by Fernbach some year or two ago, the factor which governs stability in connection with attenuation is the ratio of attenuation to attenuability. (A. Fernbach, Ann de la Brass, et de la Dist. 1905, 8, 193—195. Also Journ. Inst Brewing, 1905, p. 581.) If there are two worts, one capable of attenuating to 55 and the other to 65 per cent., and if the actual attenuation of the beer be 55 and 60 per cent, respectively, the beer with the higher attenuation will be the more liable to be attacked by foreign organisms than that which is less attenuated, because the former is fully fermented, and the latter is not. The attenuation, therefore, is not a matter depending on the will of the brewer, but is a function of the composition of the wort. If the brewer desire to modify his attenuations with safety, he must modify the composition of the wort by selecting and treating his raw materials in a manner which changes the composition of the wort in the desired direction.

In my own case, I have not had to make any changes in the composition, or the temperature treatment of the grist, the only innovation has been centered in the handling of these raw materials, and the net result is gain in extract, higher finals and fuller beers. And, as touching upon the important factor we call stability, the product of finely-ground grist has exhibited a uniform and exceedingly gratifying standard of excellence.

Discussion.
The Chairman said the paper they had heard was a very able and practical paper, and one which contained a great deal for them to think about. They felt honoured by having amongst them Mr. Montagu Baird, the President of the Institute. In the name of the North of England Section he extended to the President a hearty welcome. They in the north sometimes felt themselves very far removed from the headquarters of the Institute, and that if they were nearer they could enter more into its activities. At the same time, their Section had a great deal of work to do locally, as it was a large centre of the brewing industry. The Section was doing all possible to promote the interests of the trade, and help to put before the public—who in these days were skeptical of what they drank—the best article that could be produced.

The President of the Institute thanked the Chairman for his kind references to him, and the members present for the heartiness of their welcome. He assured them that he appreciated his visit to Manchester, because he felt that in that city he was amongst old friends. When the Institute did him the honour of electing him to the position of President, his first thought was how best he could further its interests, and it occurred to him that a personal visitation to the various sections was a desirable course, especially as ho found that at headquarters there was a lack of information about, and they were a little out of touch with, the sections. By the visits which he proposed making to the different sections he hoped they would be brought into closer relationship with themselves and the central organisation. He must plead ignorance of such a deep subject as Dr. Stanley Smith had brought before them. Although not a practical brewer, he was a practical maltster. He could not, however, forgot the old saying that “Good beer is made on the kilns,” the maltsters therefore rather fancied themselves, and in saying this he would add an expression of the pleasure it gave him to see present Mr. Sandars, a maltster, of  Gainsborough. Some little time ago he, the President, visited the United States of America, where he found—go-ahead people as they were—the brewers wore a long way behind the English brewers in so far as having an Institute was concerned. In this respect they might be said to be in their infancy, and they were much enamoured of the Institute in England. At one of the meetings he heard the Institute Journal very favourable spoken of. It was constantly referred to as a “Standard work.” If there were any in this country who thought the subscription to the Institute was at all high, he would say that those connected with the business in America looked upon the Journal in itself as being worth the amount of subscription, independent of the benefits derived from membership. He happened to be present at a meeting in New York, when a paper was read on a subject of special interest to him, namely, the purchase of malt on the basis of analysis. This matter had recently engaged the attention of the American Institute. On this point a diversity of opinion existed amongst American brewers, but there was a disposition to come into line with what was done by brewers in this country. In America they were improving their methods upon a scientific basis. They were well abreast of the times as brewers, but they certainly did not know the value of science in the malt-house as it was known in England. To him their process of making malt looked like the destruction of fairly good barley. At Washington he was introduced to the Department of the Board of Agriculture, which was concerned in the cultivation of cereals. The bureau bad a large staff engaged in the study of various soils and grounds. At the time of his visit they were investigating the nature and growth of barley. They were determined to grow their barley, and the Department had imported seed from all over Europe and other countries. By this means they were finding out what barley was the best suited to their brewing, and also what seed best suited their soil. They had the same difficulty in regard to wheat, and for wheat growing some parts of America were played out; but they had now ascertained, through visits made to Australia, the class of wheat that was the best suited to their land. As to the brewing industry in England, they would all be prepared to admit that for a number of years trade had been extremely dull, and it had been taxed almost beyond endurance. Whilst all brewers were competitors—for whether their trade was “tied” or not, they competed for public patronage—he thought the time was coming when they should show a more united front. Meetings such as that, where brewers were brought into contact, and held social intercourse, might help to break down the barriers of competition. They had at present arrayed against them a pretty strong “team”; but if the brewers did not unite, he was certain their opponents would score over them eventually very considerably. With regard to the Budget introduced to the House of Commons a few days ago, the only- point in it that was cheered was that referring to the serious falling-off in the Excise returns. It was not a nice thing to feel that they were going to suffer, but they had been warned that the first important piece of legislation next year was to be a temperance measure. How this would affect them could not yet be foreshadowed, although it was believed the Bill would propose a curtailment of the hours of opening both on week-days and Sundays. Turning to the profession of brewing, the President said whilst a great many of the younger brewers started with a desire to know something of the chemistry of brewing, he was afraid they fell away from the pursuit of this knowledge when they left the laboratory where they spent their pupilage. He felt that the Institute went a long way to fill the gap thus created, and keep the young brewers in touch with what was taking place in the world of science as applied to their profession. The reading of the Journal, also, would give them much enlightenment and instruction. He appealed for an increased interest in the work of the Institute. Personally, he felt highly honoured that he should be the first maltster who had held the position of President, and this implied a recognition of the sister industry of malting. Although science had been known to brewing for many years, it had rather suddenly been sprung upon maltsters, and it behooved them to keep abreast of the times.

In conclusion, he congratulated Dr. Smith upon his excellent paper, and added that he was present at Edinburgh when he read the first part of it. He invited the members of the Institute in Manchester and district to prepare papers in their leisure hours, assuring them that they would be listened to with much interest, and greatly appreciated.

Mr. W. B. Roberts said the question of extracts was one of the utmost importance, and he felt personally indebted to Dr. Smith for his paper. He incidentally mentioned that Mr. Harris, whose patent Dr. Smith had alluded to, was a former pupil of his, and regretted his absence. He agreed with the President that beer was manufactured on the malt kiln, and the necessity of a brewer having a chemical training, because he held a watching brief on behalf of his employers and the honest maltsters.

Mr. T. Hyde, referring to the “buoyancy” described by Dr. Smith, said he presumed he would regulate the speed of the taps in accordance with the volume of liquor sparged on. Probably this point had a lot to do with the increased extract.

Mr. Slocock asked why it was necessary to have a separate feed for each sparge arm?

Mr. Sandars enquired from Dr. Smith if he had noticed any proportionate increase of extract in finely ground high-class malt as compared with malt of a second quality ?

Mr. Marriott enquired how the fine spray was distributed from the sparge arms?

Dr. Smith replied through holes 0*032 of an inch, which was as small as they could possibly be made.

Mr. T. Hyde said it was well known in lager beer brewing that the grist was ground very fine, but in that system no regard need be paid to clarification, as the beer was chilled and filtered before being sent out. He was afraid that this new system advocated by Dr. Smith, of which fine grinding was part of the process, might result in turbidity with their English system of brewing.

Mr. Slocock asked what was the improvement in pounds extract on this system as compared with the old one whore ordinary crushing and sparges were in operation?

Mr. Sandars said 25 Seek having been taken as the standard for laboratory grinding, asked Dr. Smith if he considered 25 very fine grinding for a brewery, and whether he considered it the best standard that could be adopted for the laboratory, or whether, in his opinion, it .would not be better to have as standard a coarser ground malt, which would more clearly show up the under-modification of a common malt?

Mr. Haigh enquired whether it was suggested by the author that by his process the mill rolls could be set as to grind the grain to powder? It was generally considered that 1/24 of an inch was about the maximum, with safety in the mash-tun. The author had not mentioned the velocity at which the rollers should be driven. This was certainly of importance. Had the author analysed his worts and beers to ascertain to what the increased extract was due? Was it to starch conversion products, nitrogenous, or inert matter? If to nitrogenous matter, it would certainly have an important bearing on the stability of the beers.

The Chairman, in proposing a vote of thanks, said the subject that had been dealt with appealed to them in these days of keen competition. In the old days it did not matter very much what sort of extract was obtained, for the profits were always there at the end of the year. Nowadays, however, the question almost meant profit or loss.

Mr. J. G. Wells, in seconding the vote of thanks, said he did this with a feeling of gratitude to the author, because in the North of England Section they had experienced some difficulty in arranging for papers. They were delighted to see Dr. Smith, whom he hoped would not think it unkind if he (Mr. Wells) ventured to criticise his paper somewhat. Even in Manchester brewers admitted that they left too much in their grains for the farmers’ cattle to feed upon. Dr. Smith’s paper was an attempt to improve upon that state of things; but his attempt to reduce the amount of starch that they gave to the farmers at the present time seemed to him to be a sort of screen to the bad maltsters. If they bought malt properly made and with no hard ends they would not need the elaborate process of dealing with it as explained by Dr. Smith in his two papers. He felt that now brewers were becoming more particular as to the sources of their malt supplies, and, in many cases, were acquiring their own makings (and in this way getting to know thoroughly how their malt was made), it was improbable that they would have to adopt the elaborate process which had been described. He was not very clear on the point of the maximum extract which Dr. Smith obtained by mashing from finely-ground grist, and using the patent sparger, but he thought he mentioned 91 lb. He (Mr. Wells) did not consider this at all high—in fact, it seemed to be rather low. He thought that, with a mixture of good English and good foreign malts, 95 extract could not lie considered exceptional. If he was right in assuming that 91 extract was the maximum obtained by Dr. Smith, then he considered they might continue to work on the old lines. Brewers, he continued, were often told that they were old fashioned, and got their backs up at anything new. Whilst not admitting that this was so, he urged that, nevertheless, there were times when they might take up this stand with advantage. So many fads were introduced to them that they had, at times, to resent innovations somewhat As to the quality of the extract obtained, he had been reading a recent article in a German paper on this subject. In this case the extract was from finely-ground grist, but there was a resultant objectionable red tint in the wort which some of them had no doubt noticed. An observation to the same effect was made in 1853, so that as long ago as 50 odd years brewers were not very far behind in their methods. With regard to sparging, brewers in Manchester were particularly favoured in having a very soft water which did not rapidly scale; but from his experience in other parts, where the water was much harder, if Mr. Harris’ sparger had been used it would have had to have been scaled every day. When brewing at intervals of every six or seven hours, the scaling of the sparger between each operation did not enhance the rapidity of brewing operations. As to grist, if he were to mash grist of the degree of fineness alluded to in Dr. Smith’s former paper, ho did not doubt that with proper care and precaution he should be as successful as Dr. Smith; but, at the same time, he should not want to devote his whole time to superintending the mashing operations. A brewer had other things to do than attend to mashing and sparging only. His conclusion was that if from 91 to 95 extract could be obtained in the ordinary way, it was not necessary to increase the degree of fineness of grinding and sparging already obtaining.

The proposition having been adopted,
Dr. Stanley Smith, in reply, acknowledged the cordiality of his reception. That was the first occasion on which he had visited the Manchester Section, and he hoped it would not be the last. Ho very much appreciated the remarks that had been made about his paper, which he had endeavoured to make a really practical one. The questions which had been put to him, and Mr. Wells’ kindly criticism, he thoroughly appreciated. It seemed to him, if he had done nothing else, he had aroused an interest in the mode of grinding, mashing, and sparging. He welcomed anything that tended to make brewers, especially the younger ones, take a deeper interest in the apparatus used in brewing. He knew they wore all too apt to take things as matters of fact without in the least studying how such things came to be, and what was the specific use of each. He thought that nearly all the questions that had been put to him had been answered in the first portion of his paper, which he invited them to read in the Journal. Mr. Hyde’s question as to buoyancy was practically answered in his former paper; but, as he has explained, within the last three or four months he had found that in using a fine grist a great deal of trouble was obviated in running off the first copper exceedingly slowly, which really meant that the very minimum of mash-tun disturbance took place. In reply to Mr. Slocock, he would say that he would find all he wanted to know of Mr. Harris’s sparger in his specification of the patent. The whole thing was designed to get as much power on the arms, and as great a speed as possible. Mr. Hyde condoled with him for having too much in his beers, and thought he (Dr. Smith) must have had trouble in the summer; but he stated in his paper that he weathered last summer very successfully. The experiments he had explained in the two papers wore the result of more than 12 months’ work. He was happy to say the beers had never been more popular, nor the sales larger. Neither had ho had any of that curious red tint which had been associated with the brewing by their Continental friends. Mr. Sandars asked a question as to fine grinding. Mr. Sandars was a very able maltster, and produced only the very finest malt, and with him it hardly mattered whether the malt was ground or not. Personally, he hoped to see the day when skinless barley would be successfully malted on the floors. He concluded by renewing his thanks for his reception and for the way the paper had been received.