MEETING HELD at the CALEDONIAN STATION HOTEL
on TUESDAY, DECEMBER 15th, 1908.
Mr. JOHN S. FORD in the Chair.
The following paper was read and discussed:—
Condition and Head on Beer
by A. E. Berry
Condition and head on beer are in some respects inseparable, and although I had intended principally to speak more especially with regard to those unfortunate periods of flatness that occur in breweries from time to time, I find it impossible to do so without also introducing what is familiarly known as “Condition”. It is a sine qua non of successful brewing that a beer should carry a lasting and attractive condition, combined with a compact foaming head.
During recent years the public have become much more exacting in this respect, and to some extent the advent of carbonated beers has accentuated the demand for increased sparkle and life in the appearance of our national beverage. So much is this the case that beers that would have passed muster as regards their foaming capacity a few years ago would now be received in the Trade with disapproval; and it was in consequence of a few complaints received from different parts of the country as to flatness that led mo to the conclusion that a paper dealing with this subject would be of some interest to the Scottish Section.
Flat beers are undoubtedly a grave source of complaint to the brewer, and especially is this the case when the beer is in bottle, because there is then no means of overcoming the difficulty, such as presents itself by priming a beer in cask. “With the gradual tendency to reduce gravities, both on account of public demand and also for economic reasons, it is much more difficult to produce by natural means an attractive foaming condition than was the case a few years ago; for instance, in the early days of India Pale Ale, beers were brewed of much higher gravity, and were generally allowed to mature through a series of fermentations, but such a condition of affairs is only possible in a few cases at the present day.
The demand for beers of high gravity decreases year by year, and in consequence the viscous extract, so valuable for heading properties, becomes less, necessitating increased care and vigilance to produce beer free from flatness.
It is this gradual change in the public demand for lighter beers and the general reduction of gravities in many parts of the country that has compelled brewers to adopt artificial means of improving the condition and head, by saturation with carbonic acid gas. Especially is this the case in different districts of England and Wales, and where suitable brewing methods are employed a very attractive appearance is obtained; it is a well-established fact, however, that something more than simple saturation with CO2 is necessary to produce and maintain an attractive head.
When the gas is forced by means of pressure into beer, part is held in the form of solution by the emulsified constituents, and the appearance and condition of the head on these artificial carbonated beers entirely depends upon the character and composition of the viscous bodies that are in solution. The same applies to beers naturally conditioned, and no matter what pressure is employed, unless the emulsified constituents are present in sufficient quantity, the resulting beer will not carry a lasting head.
In other words, the head retaining property of beer is absolutely dependent upon its viscosity, and it is difficult to say whether this viscous extract, which is of a colloid nature, is actually in solution; personally, I am of the opinion that, to a certain extent, it exists in the form of semi-suspension or a very fine state of division, in consequence of the fact that one frequently finds these bodies being thrown out of solution in beer due to slight disturbances such as fall in temperature, increase of acidity, or alcoholic strength. When these viscous colloidal bodies are thrown out of solution, or removed from the beer, it is an undoubted fact that the head and foaming capacity decreases, and anything that tends to agglomerate the colloids from solution detracts from the permanency of the head.
These viscous bodies are principally imparted to the beer through the medium of the malt and hops employed, and consist of hop resins, malto-dextrins of different types, and various forms of proteins and nitrogenous substances.
Taking first the proteins and their derivatives, the value of these important ingredients in beer can be demonstrated by dissolving a small proportion of one of the albumoses or peptones in water and shaking, when it will be found that the solution possesses exceedingly strong and attractive foaming properties, and if it is carbonated it carries a most persistent head.
A few years ago I made a number of experiments on white of egg with the object of preparing a body that would not only assist in the clarification of beer, but would also impart properties which would be of value in increasing the foaming characteristics, and although both those requirements were fulfilled, yet all preparations from white of egg possess objections that I found made it quite unsuitable for use in beer. My preparation—which was undoubtedly of the composition of albumoses—was so powerful that as little as one part in 5000 produced a most lasting and persistent head of a fine close character.
I experimented not only with the preparation from white of egg, but also with the deutro-, hetero- and proto-albumoses which were prepared from peptone. In addition to increased foaming properties, I found that in every case the palate-fulness of the beer was undoubtedly improved, and this is a point that seems to require further investigation. The effect of the albumoses upon the palate-fulness was most marked with some beers, and as so much now depends upon this important feature in a beer, I believe that even still greater benefit could be derived from a closer study of the advantages and methods of increasing or improving the albumoses.
R. Wahl, of Chicago, Windisch, and others have done much work in isolating the various nitrogenous bodies that are supposed to increase the foaming capacity of beer, and whilst a few of the results differed in some respects, yet all are in agreement as to the advantages and great value of the presence of albumoses.
Albumoses it would seem most completely fulfil the function of creating the foam that a beer should carry, and when these nitrogenous bodies are combined with a sufficient quantity of carbon dioxide one is sure to get an attractive and lasting head.
I am of opinion that with every flat beer there is a deficiency and falling-off in the percentage of albumoses, and there is no doubt that a closer study of the albumoses during malting would be of considerable benefit to the brewing industry, not only on account of the foaming power they possess on the resulting beer, but also from the point of view of the extra palate-fulness and general improvement in character that they impart.
As an example of the palate-fulness that is imparted by the albuminous and nitrogenous matter existing in beer, it is only necessary to call to mind the very great difference that occurs after a beer has been submitted to chilling process, such as is the case when it is about to be carbonated; all brewers recognise how the fulness suffers, and in many cases the loss of the trifling percentages of nitrogenous and albuminous matter makes a difference of a pound or two upon the palate.
The formation of the valuable albumoses is an interesting study, and there is no doubt that much benefit to the brewing industry would accrue from further investigation as to the behaviour of these constituents. It is the general opinion that they are formed by the action of the enzyme peptase upon the albuminoids during germination of the corn, and that they are also created during early stages in the mash-tun.
The albumoses are obtained from the insoluble proteins, and during the malting process act as food to the growing plant; but if malting is hastened too much, or insufficient time given to the corn on the floor, results indicate that the yield of albumoses suffers, and there is no doubt that some mashing temperatures are also much more favourable to the production of these valuable bodies than others.
Experiments were made with regard to the head-producing constituents of malt and other grain, and it was found that in addition to barley, wheat also contained a valuable heading principle, I am of opinion that rice, wheat, and other grain contain heading principles which are soluble in alcohol, and if suitable methods are employed I do not consider the use of raw grain need act in any way prejudicially to the foaming capacity of beer.
As a matter of fact, I am of the opinion that one of the benefits that were supposed to accrue—especially in the olden days—from dressing the fermentation with malt flour, consisted very largely of the increased foaming characteristics that were imparted to the resulting beer.
The bynin of malt (modified hordein of barley) possesses the faculty of producing considerable foaming capacity when added to wort, and when malt flour is used as a dressing, in addition to the influence of the existing diastase, it should not be forgotten that there are the heading benefits to be considered; at the same time it is very questionable whether this ultimate improvement upon the head of the resulting beer is worth the risk that occasionally arises from dressing the fermentations with flour.
It is generally assumed that the albumoses arc not coagulated by heat, precipitated by the hops or assimilated by the yeast, but that they pass right through fermentation and remain in the finished beer to exert their beneficial properties. I am not aware, however, of any experimental evidence in support of this statement.
The peculiar flatness, however, that is noticeable with some beers that have attenuated to a low degree, leads one to the conclusion that there is not only a decrease in the dextrinous contents of the wort, but that in the assimilation of nitrogen some of the valuable albumoses have either been precipitated or extracted, and there is undoubtedly room for further investigation of this very important point.
The peptones arc very closely allied to the albumoses, and although they possess heading properties, but in a lesser degree than the albumoses, yet their value in this respect is destroyed owing to the fact that they run great risk of elimination, by being absorbed in the form of food by the yeast.
There are probably other complex nitrogenous constituents that possess valuable foaming properties, and in order to derive the maximum benefit from these, I nm of the opinion that it is necessary not only to adopt careful malting methods, but also what one might term, “coaxing treatment in the mash-tun”, with one malt as compared with another, often varying the temperature and methods.
The most viscous constituents in wort that advantageously influence the head and condition are the dextrine, which may exist in various forms and conditions, generally in the form of malto-dextrin. These bodies undoubtedly have very great effect upon the foaming capacity, palate-fulness and general character of the beer, and as they do not attenuate under ordinary conditions, their benefit is lasting.
In the production of light carbonated beers, and the compulsory lowering of gravity, experience has shown that a more dextrinous wort is essential, and it is probable that there is even still further room for improvement in this respect.
With lower gravity beers, especially the private trade beer in bottle, there has been a decrease in the percentage of .alcohol, and when this constituent decreases, the head suffers, because alcohol undoubtedly helps the foaming capacity. On the other hand, however, whilst there has been a loss in the alcoholic percentage, this has been more than compensated for by increasing the percentage of dextrinous and viscous constituents.
Under existing brewing conditions it seems almost imperative that mashing heats should be employed that will produce a satisfactory proteolytic action and a resulting wort containing a suitable nutrient medium for successful reproduction of yeast; when such is the case it is at times unfortunately impossible to produce from some malts the necessary dextrinous character that is required for very low gravity Leers, especially those that are intended for bottling and carbonating.
In these cases considerable assistance can be derived by imparting at some later stage increased or improved dextrinous character by other means, and without this property it is impossible for carbonic acid to be efficiently held in solution.
It might be well to mention at this stage how the carbonic acid is held in the beer, and there is no better example of this than a comparison between a carbonated liquor, such as beer, and soda water, and noting the resulting head, when the great value of a dextrinous and viscous medium is at once apparent.
When beer is carbonated, the bubbles of gas exist in a very minute form, and being lighter in gravity than the beer itself, rise gradually to the surface. Of course, the higher the extract of the beer, the firmer is the carbon dioxide held, and slower and more gradual docs the gas ascend. As the carbon dioxide reaches the surface it creates the head, forming a layer on the top of the beer, which acts as a cover, and retards its further evolution. The smaller and more confined the bubbles of carbonic acid, the better and more compact will be the resulting head on the beer, and a very good example of this is seen when comparing a quick draught beer with a beer that has been gradually conditioned in bottle and slowly developed increased pressure over a period of a few months.
Speaking generally, the foam-destroying constituents in beer are chiefly of an oily character, and are so objectionable in their behavior that even when mixed with other bodies that would be favourable, they have the power to more than counteract them. I am strongly of the opinion that the oil from maize, barley, and other cereals has a very prejudicial effect on the foaming capacity, and, of course, as we all know, they are equally objectionable from the point of view of palate-flavour and fulness. The essential oil of hops does not act in such an unfavourable manner, and the experiments that I have made in this direction rather tend to demonstrate that the extract from hops improves the head on beer, and this probably arises from the very valuable hop resins that have great influence in this connection. Every brewer is aware of the importance of keeping at a minimum the percentage of oil in maize, but with decreasing gravities, and whenever flatness is apparent, the percentage of oil in the goods that are being used is a point that should certainly not be overlooked.
The effect of acidity is also worth consideration, and my experiments indicate that after this reaches a certain percentage it certainly produces flatness. Samples of beer were taken, and the foaming capacity noted carefully from day to day, and alterations were made that gradually increased the percentage of acidity; this was continued until it was found that the head was almost entirely destroyed. For instance, a beer that had original acidity of 005 per cent, possessed a very attractive head and strong foaming capacity, and as the acidity rose to 0*1 per cent, there was practically no decrease in the foam, although immediately this percentage was exceeded the head gradually diminished until the beer reached 0*3 per cent., when it was distinctly flat. It is also interesting to note that, as a beer increases in acidity, the carbonic acid when rising appears to form larger envelopes of gas and a coarser and less attractive head, and consequently the brewer has a combination of difficulties when acetic, lactic, and other acid forming bacteria gain access to his plant, or enter at any stage whatever into the brewing process.
A further series of experiments were made to ascertain if the effect of acidity on the head was confined to acetic or lactic acids, or if the results were common to both. These experiments indicated that lactic acid has not the same deteriorating action on the foaming capacity as acetic acid, although even when this constituent exceeds 0·1 per cent, it is certainly detrimental, but in a lesser degree than acetic.
It is interesting to note that some of the higher alcohols have a most destructive action upon the foaming capacity of beer, and I have no doubt the flatness in some breweries is due to the fact that certain foreign types of yeast are present during attenuation which after wards give rise to these higher alcohols, and accordingly act disastrously on the head. For instance, amyl alcohol, amyl acetate, fusel oil, and several other alcohols and esters, even when present in exceedingly minute quantities, have a crippling action upon the foaming capacity. I had to make these experiments by adding very small quantities (fractions per cent) of the different alcohols to beer in good condition, noticing the flattening effect, but the results were such as to make it highly desirable, when flatness occurs in a brewery, to look to the presence of foreign yeasts and ferments that would be likely to produce higher alcohols of the nature I have described.
Before leaving the description of the constituents that act adversely upon the foaming capacity of beer, it might be as well to mention that very well known factor—Temperature. Especially at this season of the year flatness will occur and be found due to a fall in temperature, and probably more complaints arise from this cause than any other. In the majority of cases this can generally be overcome by placing the beer for a short time in a store a few degrees higher in temperature, but this is not always convenient, and, indeed, if a beer has been carefully brewed, it ought to stand the vicissitudes of temperature which must be expected during the winter season.
Unfortunately, with the chilling of beer, some of the valuable nitrogenous bodies and colloids that make up the viscous constituents in beer are frequently thrown out of solution and precipitated, depriving the beer for good of their valuable property of producing foam, and even when the beer is placed in a store with a higher temperature it is not always possible to again drive them into solution. I am of the opinion that the cloud that is produced during chilling, and the bodies that are precipitated, are amongst the most important foaming constituents existing in beer, and the fall in temperature that occurs in the winter season, and so frequently produces flatness, emphasises in my mind the necessity for varying the brewing conditions to suit this particular season.
In addition, it is also frequently desirable to employ for the winter months a priming of different character to what has been in vogue during the spring and autumn, and beers that are chilled and become cloudy can generally be remedied by a judicious application of a suitable priming, without any apparent loss in the condition or other properties of the beer.
There is another point that would result in flatness unless care were exercised, and although it may appear a trivial one, there is no doubt that many complaints of flatness have been due to a little carelessness in this respect, viz., with regard to seeing that all casks are well topped up and filled, and whore attention is paid to this point there is a better chance of the beer holding the carbonic acid in solution, and much greater benefit is derived than many people appreciate.
It has been stated that the use of sulphites, antiseptics, and different preservatives has a prejudicial effect upon, not only the head, but also the condition of the beer, and to a great extent this is true. Some years ago I was engaged in ascertaining the action of finings when clarifying beer, more particularly with regard to what is called on the Continent “fining out of the top”. During this investigation I had occasion to notice the effect of sulphurous acid and bisulphite of lime upon the evolution of carbonic acid, and I finally arrived at the conclusion that when some sulphites are present they undoubtedly retard the generation of gas, and when such is the case they must also have an effect on the head and condition,
When a sulphite is used as a cask preservative, I believe it acts in the following manner:—It absorbs the oxygen that is dissolved in the beer—which in the ordinary way would lead to oxidation of the extract—and at the same time the sulphite robs the acid-forming bacteria of one of their principal sources of subsistence. It might also be assumed that the action of the sulphite is detrimental to the activity of those surplus normal cells which are necessary for the production of an attractive cask condition, and in consequence acid sulphites such as bisulphite of lime might be considered objectionable. A large number of experiments have been made to investigate this important point, using quantities of sulphite such as one might expect to be used in the preservation of beer, and these experiments demonstrate that when a sulphite containing free acid is used, there is undoubtedly a slight flattening effect, and the condition generally suffers.
Bisulphite of lime contains a large percentage of free sulphurous acid, and with some beers I found it had a most marked flattening effect, throwing a decided check upon the evolution of the carbonic acid, which is the very essence of condition. When the preservative, however, is firmly and entirely attached to a base such as in the case of some sulphites of sodium, potassium, and calcium, there is not the same .adverse result; and when used in ordinary proportions, I have been unable to detect that these fixed sulphites act prejudicially in any way. Even bisulphite of lime differs in its action in this respect, and whereas its flattening effect on some beers is very noticeable, in other cases it is not so, especially with a beer that is racked already showing fair signs of condition. On the other hand, if bisulphite of lime is added to beer that has been racked for two or three months with the intention of increasing its stability for a longer period, the flattening effect is apparent, whereas with a preservative in which the sulphite is entirely combined with the base the effect is not the same.
The stage at which the finings is added may also act adversely towards the resulting head upon the beer, and I am firmly of the opinion that if it is used too early, i.e., too soon after racking, injury results—especially when the isinglass has been cut with sulphurous acid: not only does tho sulphurous acid retard the action of CO2, but in a mild degree throws a check on secondary fermentation; and where flatness has been experienced it will undoubtedly be a step in the right direction to delay the fining of the beer as late as possible, and especially to avoid a finings that has been cut with sulphurous acid, and employ a clarifying agent prepared by another method.
Some finings when prepared with sulphurous acid have undoubtedly a flattening effect, whereas, on the other hand, I believe that finings can be prepared that are beneficial rather than otherwise in this respect. If a beer shows signs of developing excessive condition, especially during periods of hot weather—when the tendency is all in this direction—it is an advantage to add finings as soon after racking as possible, as this is sure to help to keep down too rapid an evolution of CO2, and the formation of too violent a condition.
It is an interesting point to remember that some finings, when carefully made, and especially when prepared from different types of isinglass, possess important properties in improving the foaming capacity of beer, as they impart colloids of a nature that remain in solution, and this is a point that requires very careful consideration from the brewers1 point of view. Isinglass that has been under-modified, and not completely cut or emulsified, not only produces a resulting finings that clarifies badly, but at the same time lacks the beneficial effects of a finings that has been carefully and skilfully made, All good isinglass finings impart properties which, when combined with a sufficient amount of carbonic acid, benefit the foam and condition of beer, and if an emulsified form of isinglass is added to a liquid such as water, and carbonated, it will be at once noticed that valuable foaming properties exist.
I have investigated cases of flatness in beer that has been entirely duo to the absence of a sufficient quantity of surplus yeast cells in the carriage cask, and unless sufficient yeast is present it is absolutely impossible to generate the necessary carbonic acid to create the life and sparkle that are desired. I have seen such cases rectified by the addition of a very small quantity of yeast through the bung-hole of the cask and rolling, although it is a procedure which should never be necessary. Especially during the winter and cold weather the absence of a sufficient quantity of surplus yeast cells in the cask is likely to be felt, although cases of this description are fortunately extremely rare.
A brewer generally becomes troubled with flatness quite suddenly, and frequently without any apparent alteration in the usual brewing methods, making the difficulty all the more troublesome. Among the different complaints that have been brought before my notice, beers have been described not only as “flat”, but sometimes as tasting more “sugary” than usual, whilst at other times I have heard them referred to as being “too clean”. Generally speaking, flatness arises from faulty wort composition, probably due to the mashing heat being either too high or too low for the malt in use; when the former is the case, beers carry an excessive percentage of a hard type of maltodextrins which resist primary fermentation, and the formation of desirable nitrogenous bodies must have suffered in the mash-tun. When the beer passes into cask the yeast is incapable of breaking down the dextrins and producing at a sufficiently early date the necessary life and sparkle.
As a rule, flatness that is due to too high a mashing temperature can be to a certain extent overcome by well rolling the casks, and especially by storing at a little warmer temperature, but during the winter months it is difficult to remedy this in reasonable time. If the beer, however, can be kept for a little longer time it will invariably right itself and come into condition within the space of a few weeks, but under many conditions this of course would be impossible. On the other hand, if the mashing heat has been too low the wort will carry too high a percentage of readily fermentable sugars and lack the necessary dcxtrinous character that is essential for condition and foaming capacity; in consequence, during primary fermentation the greater part of the residual extract disappears and the beer passes into cask or bottle under flattening conditions. In a case such as this, however, the difficulty can generally be overcome by judicious priming.
With regard to the mashing temperatures, it is important to remember that low heats favour the formation of albumoses, which are exceedingly valuable in creating a good foam, whereas, on the other hand, high mashing temperatures diminish their formation, and consequently act detrimentally towards foaming capacity. Careful adjustment of temperatures according to variation in the malt employed is absolutely essential if satisfactory head and condition is to be expected, because the heat that has given satisfactory wort and a resulting beer with a good lasting head with malt over a certain period would produce a beer of different condition and head when applied to a change in malt.
It is essential to secure malt that has been efficiently cured in order to produce a healthy wort, as flatness is often duo to the use of under-cured malt; and if such goods are used in conjunction with low mashing and sparging heats, it is impossible to obtain satisfactory results. When a beer lacks the necessary life and sparkle due to the above-mentioned cause, the difficulty can frequently be overcome by the introduction of a little sweet wort, but, to my mind, the application of a suitable priming produces better results.
If an analysis were made of the different complaints that one receives of flatness from various parts of the country, I think it would be found that in the large majority of cases the trouble arises through faulty wort composition, due to unsuitable mashing temperatures. It is difficult to decide which temperature will give the best results during different periods of the year, as the character of the yeast and the goods employed must also be taken into consideration. During the hot weather the action of the yeast upon malto-doxtrins is much more energetic than in the winter months, and, in consequence, the extract from these bodies is split up and attenuated with greater facility, and therefore some beers during the summer months suffer from flatness on account of temperature.
The use of primings has been of inestimable value to the brewer in this respect, and it is not too much to say that without this means of finishing beer, flatness would be very much more prevalent, and lack of condition would be a very general remark; in fact, it would be impossible to brew many of the low gravity beers now offered to the Trade possessing a sufficiently attractive condition, without the use of priming.
I am of the opinion, however, that even greater benefits can be obtained by the judicious use of a priming, and, unfortunately, sufficient care and thought are not always devoted to this important point. Many brewers are ignorant of the true character and composition of the priming they employ, and if successful results are desired this should not be the case.
In addition to the benefits which primings undoubtedly exert towards finishing the beer, there is also the extra fulness which they impart, and in many districts—and especially in the winter season—it would be very difficult to get on without them. Not only should a priming be composed of a blend of sugars in such a manner as to produce fulness, condition, and foaming capacity, but in many districts they are and can be employed to create certain characteristic flavours.
It has always been my opinion that in the winter months priming of a more readily fermentable nature should be employed than during the spring or autumn, or even the summer, and I venture to say that a marked improvement could be effected in the general condition of many beers if a closer study were made of this point. The character of the priming should also depend upon the length of time that a beer is expected to be in the Trade: that is to say, whether for a few days, weeks or many months.
The application of primings alone, however, will not always overcome flatness, as a beer must carry the necessary surplus yeast to generate a steady flow of carbonic acid. The time at which a priming is to be added must not only depend upon the character of the beer but also on the particular composition of the priming.
When considering the general question of condition and head on beer it is necessary to look at every aspect of the brewing process, and no doubt improvement could sometimes be effected by a better system of liquor treatment. Unfortunately, from the point of view of this paper, little attention is paid to the action of the saline matter in brewing liquor, and in order to ascertain what benefits, if any, are derived from this source, I made some years ago a number of experiments by using the usual hardenings, such as gypsum and the chlorides and sulphates of the alkali metals, at different stages of the brewing process. In the course of these investigations I discovered that different hardening salts help to increase the precipitation of certain forms of nitrogenous matter, and when present to an excessive amount affect prejudicially the ultimate head upon beer.
I also made some experiments by using the chlorides of calcium and sodium in the copper, and as long as the proportion does not exceed 30—40 grains per gallon, I am of the opinion that the effect is beneficial, or in other words, a judicious application of these hardening salts would in most cases effect a considerable improvement in the head of mild ales and black beers. In the brewing of pale ales, however, I am of the opinion that too liberal an application of gypsum has an unfavourable effect, but I am not at present in a position to give any actual figures on this point as a considerable amount of further work is necessary.
The bynin of malt is most soluble in water containing sodium chloride, and consequently brewing liquors containing these saline constituents—especially calcium chloride—distinctly favour the persistency of head, and waters which contain sodium carbonate and sulphate are improved in relation to this question by using a little calcium chloride to decompose these salts.
Before concluding this paper I would like to speak of the peculiarities of the head upon one class of beer that is fortunately rarely troubled with flatness, viz., stout and porter. As a matter of fact, the rich foam on the head of some well-known brands of stout and porter is one of the chief characteristics of their great popularity, and while in some districts there is a demand for the head on black beers to be of a rich brown character, in others the public prefer what might be termed an “almost white head” upon these beers.
The public become every year more suspicious with regard to any variation, not only in the colour of the beer, but also the colour of the head; and, generally speaking, black beers increase in favour when they carry a nice rich brown head. It is interesting to note how the head on some stouts is forced upwards, rising in the middle, when poured into a glass; this peculiar feature is due to the clinging manner in which the viscous particles hold themselves to the sides of the glass, and it is seldom seen in so marked a degree on light colored ales. The attractive condition and head on black beers is due to the high dextrinous contents existing in the wort from which they are brewed, resulting partly from black malt, but in many cases it is rather due to the different types of caramel that are used in the copper; some beers that are noted for their richness of character undoubtedly owe their popularity to the use of certain caramels. The production of stout and porter that will carry an attractive condition and lasting head does not present the same difficulties as in the case of pale or mild ale.
The Chairman enquired if the flattening effect attributed to increase of acidity were due entirely to the acid itself, as along with formation of acid by bacteria there might also be concurrent proteolysis of certain of the foam-forming colloids. Did the direct addition of similar amounts of acids to sound beers have the same effect? In which case was the decrease in foaming capacity due to precipitation of some of the colloids? He agreed with Mr. Berry that during the “chilling” of beers the deposition of nitrogenous and other matters detracted not only from the foaming capacity but also from the palate-fulness. With regard to the influence of maize oil in destroying foam, this was no doubt due to resulting alterations in the surface tension, and in this connection one would hardly expect increase of alcohol to assist foam formation. Possibly, however, the favourable result was due to the stronger alcohol altering the state of aggregation of the colloids, so that they more readily separated in the membrane condition as foam. On general grounds as the capacity of foam formation in beer seemed to depend so largely on proteins of the “albumose” class, one might expect that “forced malt” would give beers deficient in “head”, and it would be interesting to know if the lecturer’s experience confirmed this view.
Mr. Urquhart enquired if there were any known means during malting of reducing to a minimum the percentage of oil and producing a maximum yield of albumoses: at the same time producing the necessary attractive foaming condition. Also as sulphurous acid appeared to be objectionable from some points of view when used as a “cutting” agent in the manufacture of finings, what other acids could be employed which would not adversely affect the “head” upon the beer to which the finings were added? He also thought it would be exceedingly desirable if some means could be devised by which .those albuminous bodies thrown out of solution during chilling could be re-dissolved or driven into solution, in order that their beneficial properties might be maintained.
Mr. Doull asked what was the type of yeast that Mr. Berry added to beer in cask that was troubled with flatness, and how a brewer was to know what particular foreign types of yeast would produce the higher alcohols, such as he had affirmed in his paper acted adversely and deleteriously upon the natural foaming condition of the beer? He said he could not understand how sulphites, such as bisulphite of lime, could differ in their action with regard to retarding the foaming capacity of a beer, as compared with a fixed sulphite such as those which were mentioned.
Mr. Hendry apologised for missing the early part of the paper, but said he was very much interested in the remarks that had been made with regard to the deleterious effect of maize oil; he was at a loss to understand this, as good maize should be practically free from oil, and consequently he could not see how trouble could arise from this source. He said he would like to ask Mr. Berry if it were not a fact that pure cane candy was also used as a “heading” by brewers?
Mr. Bell enquired the difference between primings that were found to be suitable for the summer and winter months respectively.
Mr. Berry in replying to Mr. Ford said that he had added varying percentages of acetic and lactic acids to a beer artificially, and obtained practically the same flattening result as when the increased acidity was generated naturally. This, as mentioned by Mr. Ford, was very probably due to a disturbance that occurred in the viscous constituents of the beer with increasing acidity. The experiment of adding a very small quantity of maize oil to the beer probably reduced surface tension that would give rise to a decrease of foaming capacity as mentioned; but it was nevertheless a fact that there were records where persistent flatness in beer in a brewery had been traced to maize products employed containing too high a percentage of oil. As stated by Mr. Hendry, it is quite true that a well manufactured maize should not be faulty in this respect, but it was highly desirable that particular care should be taken with regard to this point, especially when flatness or loss of condition was apparent in any way in a brewery. He agreed that it was quite natural one might expect that the increase in the amount of alcohol in beer would not be favourable to increasing the foaming capacity, but practical results proved it to be true, and the same could be very readily demonstrated by taking an ordinary beer and adding an increased percentage of ethyl alcohol; it would at once be noticed that there was a marked improvement in the foam, and from a brewing point of view it was fortunate that this was so. Mr. Urquhart had referred to the formation of albumoses during malting, and in a question put by Mr. Ford the same principle was involved. Mr. Berry was of the opinion that the development of the albumoses was retarded if the malt were unduly forced, or if modification were taken too far. Everything at present seemed to indicate that the malt should be grown under the ordinary slow conditions, but so far he had been unable to obtain any authentic figures; considerable work being required to be done in this direction, he hoped to return to the subject at a later date. With regard to “cutting” agents that could be used in the preparation of finings in lieu of sulphurous acid: there were several such as tartaric acid, etc., but at this stage he (Mr, Berry) did not feel disposed to say more on this point. He described how the deleterious action of sulphurous acid was first brought to his notice when investigating the use of finings for what is known as “fining out of the top” on the Continent. He then discovered that finings that were “cut” entirely with sulphurous acid never came to the top, and it was impossible to remove them, as was the case with finings that wore prepared by other means. This was probably due to the fact that sulphurous acid retarded the evolution of CO2, and this put a check upon cask condition which is essential for beers that are to clarify in the Continental way. This led him to look further into the matter, and he found that other acids could be used with the same isinglass, and as long as SO2 was entirely eliminated the finings would work satisfactorily, ie. out of the bunghole of the cask. As to Mr. Urquhart’s enquiry as to a means of keeping the nitrogenous bodies in solution that had once been deposited by chilling, Mr. Berry said that the only method was a judicious increase of temperature; beers that lost their heading properties through chilling in this way recovered part of it when stored again at a temperature of a few degrees higher. This effect was only partial, and he did not think that there were any other methods that could be readily applied for accomplishing this desideratum. In reply to Mr. Doull, ho said that the yeast that was added to the trade casks to overcome flatness was a little of an ordinary pitching sample, such as was being used for the same day’s brewing. In the brewery where this was first adopted it was found that the beers remained flat even with persistent rolling and priming by all available methods. Finally, samples of this beer were put upon the forcing tray, and in one case a little yeast was added; it was at once noted that even without priming or treatment the beer came gradually into condition, and on further investigation it was found that the flatness was due to the beer being too free from surplus cask cells and thus lacking the necessary life to develop condition. The amount of yeast employed in this case was only a few grams to each barrel of 36 gallons. With regard to the foreign types of yeast that produced the higher alcohols that are detrimental to “head”, Mr. Berry said it had been impossible to ascertain this information, as the experiments were made by simply adding to beers in condition varying percentages of esters and higher alcohols as mentioned, and in no case were these generated naturally. With regard to sulphites, it should he remembered that bisulphite of lime contained about 5 per cent, of free sulphurous acid that was unattached to any base, whereas in the special fixed sulphites mentioned in his paper the whole of the sulphurous acid was firmly fixed to either sodium, potassium, or calcium; consequently it was not difficult to understand how this free sulphurous acid would act prejudicially towards the “head” on beer, and if free sulphurous acid alone was used one might confidently expect “flatness”. Again, in this case, practical experience had amply demonstrated the fact that sulphites when firmly attached to a base were not flattening agents; and, as a matter of fact, yeast could be very successfully reproduced in wort containing traces of sulphite as long as the acid was not in a free condition. Mr. Berry, in reply to Mr. Hendry’s enquiry as to whether it was not a fact that pure cane candy was a recognised heading, said he was probably confusing headings and primings; in no case could candy be included under what has been known under the category of “heading principles”.
Mr. Ford said they had listened to a very interesting paper, and he had great pleasure in calling on them to give a hearty vote of thanks to Mr. Berry.