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Terrace Garden, New York, Oct. 5, 1914.

Mr. President and Brother Chemists of the Master Brewers' Asso

ciation of the United States: It is with great diffidence that I venture to address the brewers on the subject of beer, about which they probably know more than any other men in the country. But the invitation was so flattering, and I thought it would be such a pleasure to meet the Master Brewers that I ventured to accept.

What is beer? It may be said in a few words, beer is a beverage prepared from malted barley, rarely from malted wheat. Rice or corn or their products are often used in addition to barley.

The art of brewing is one of the oldest arts of which we have any knowledge, and you consequently represent one of the oldest guilds. Brewing was known and practised by the Egyptians, perhaps 1,000 years before the beginning of the Christian era. It was practised by the Greeks, Romans and ancient Gauls. Herodotus, 450 B. C., tells us how Egyptians made wine from grain. Pliny repeats the same statement and many other of those early writers refer to it. Tacitus states in the first century A. D., that it was the usual beverage among the Germans, and further, the art of malting and brewing was probably introduced into Great Britain by the Romans. Even the Kaffirs, a race in Africa, made beer from millet seed. As early as the twelfth century beer was used in England and was especially prepared from malt made by the monks. The convent at Burton-upon-Trent became celebrated at a very early date for the quality of its ale, which was attributed to the special quality of the water. As early as 1585 there were 26 breweries in London with an output of 650,000 barrels per annum. It is interesting to note that New York City produces 10 times that quantity, and the entire United States produces 100 times that quantity. The term “ale” was used in England before the introducțion of hops and probably came from the Scandinavians. The use of hops was derived from Germany and the name beer was first applied in Germany to malt liquor containing hops. When the use of hops was first introduced in England in 1649, the English petitioned the King against their use, saying this wicked weed would spoil the drink and endanger the lives of the people, and they also petitioned the King against the use of coal for fuel in the City of London, because of the smoke which it produced, polluting the air.

The manufacture of beer involves two separate and distinct operations. First malting and then brewing. The object of malting is to so change the chemical composition of the contents of the barley grains as to render them soluble in water, so as to produce a liquid which can afterwards be subjected to fermentation. The process consists of steeping the barley in water in order to soften the husks; the barley swells in consequence and is then placed on the floor of the malt house. It begins to heat and to germinate, and from the proteids in the malt there is developed a curious substance called diastase, which has the property later of attacking the starch and making it soluble. When the process of germination has reached a certain point the barley grains are spread over a large field and turned over from time to time to prevent over-heating, and germination proceeds. When it has reached the proper point, as determined by inspection, the malt is subjected to kiln-drying, the purpose of which is to terminate germination, because if it is allowed to go over, the result would be a garden of barley plants of no further value for

beer making


The changes that take place during malting have been the subject of much careful study and investigation, and it would seem as

we had now reached at last a correct explanation of the results. It is found that during the process of malting, that is, germination, the diastase is produced to meet the wants of the plant, which in a state of nature would develop from the grain. The starch in the barley grain is a store of material, lumber we might even call it; for the building of the barley plant. In its natural insoluble condition it is extremely durable, and the result is that the barley grains may be kept and they retain their vitality for years. These starch granules are locked up in cells of the barley grains, and when the proper conditions of moisture and warmth are supplied, the diastase is developed, which converts the starch into a soluble form so that it dissolves in the water, circulates in the seed and is appropriated by the seed for the creation of the sprout and the rootlets. Careful investigation of diastase shows that it consists of two separate substances,

each of which serves its purpose. The first of these is amylase; the other substance is dextrinase. These two bodies belong to the group of enzymes. They belong to that numerous class of vegetable and animal principle found in all plants and animals, which, endowed with most wonderful properties, are absolutely essential to life. They differ from all other chemical agents for the season that there seems to be no limit to the amount of chemical effect that the small quantity of an enzyme can produce. A name has been invented which does little more than hide our ignorance to explain the character of the action; it is called catalysis, or contact action. One part of invertase can convert 200,000 times its weight of sugar into glucose. Rennet can clot 400,000 times its weight of caseinogen into casein in milk. The activity of all our digestive fluids is due to enzymes.

Next comes the brewing by which the malt is converted into beer. The crushed malt is extracted in hot water, when the diastase completes its action in changing the starch to dextrine and maltose. One part of diastase is sufficient for 200,000 parts of starch. After the malt has been sufficiently treated the solution is drawn off and this constitutes the wort. The remaining grains are subjected to a careful treatment of water to obtain as large a portion of soluble matter as possible, the worts are united, hops are added and the wort is complete. It is then rapidly cooled to the proper temperature, the yeast is added and fermentation proceeds. During the fermentation the yeast develops, attacks the sugar and liberates carbonic acid gas and alcohol. The rise of the carbonic acid gas through the liquid causes motion and the liquid is set to work. In fact the name fermentation was originally given to any chemical reaction in which gases were liberated in the liquid, as, for example, when a piece of marble was dissolved in hydrochloric acid solution. When the fermentation is complete the beer is drawn off and stored in suitable vessels, in which subsequent slow fermentation takes place and the liquid becomes clarified. The sediment of the yeast is found in the bottom of the vessels in the case of lager beer, while in the case of ale the yeast is found in the form of scum on the top. This leads to the terms top fermentation and bottom fermentation, or "Obergaerung und Untergaerung." I might add that the difference is partly due, to the temperature at which the fermentation takes place. It is found in practice that in order to produce either one of these different kinds of beer it is necessary to employ yeast yielded by the same variety. This kind of fermenta


tion is the same kind of fermentation which has been employed from time immemorial for the raising of bread. Leaven has come down from the most remote ages; it is simply dough which has been kept for several days and in which the yeast spores caught from the atmosphere have been developed into yeast. When this is added to a furnished quantity of flour and water and later kneaded together, the yeast develops over night and inflates the dough with carbonic acid gas; at the same time, as in the case of beer, a corresponding quantity of alcohol is produced. In more modern days yeast has been substituted for leaven, but the causes and the resu are the same. Some years ago when the temperance movement was running high in London, it occurred to a baker to attach a condensing coil to his oven and obtain a little condensed alcohol from the vapor given off by bread in baking. He made a great display of this and advertised temperance bread and had quite a run of trade for a few days, until his neighbor baker displayed a sign saying that he left all the gin in his bread, and turned customers his way.

This subject of fermentation has always greatly interested chemists, and for many, many years they sought in vain to explain it. A careful study of the details showed that the sugar disappeared. From 100 parts of sugar (glucose) there should be obtained, if the products were simply alcohol and carbonic acid gas, 51.11 per cent. alcohol and 48.89 per cent. carbonic acid gas, but careful experiments showed that these quantities were never obtained. There was always a small per cent. of sugar unaccounted for. It was then discovered that a certain amount of glycerine and a certain amount of succinic acid was obtained, together with small quantities of higher alcohols and compound ethers, showing that the process was much more complicated than was originally supposed.

At least one-half dozen different theories were advanced explaining fermentation, none of which were satisfactory. First we had the acid theory, which Pliny mentions. Then we had the contest or catalytic theory. This was advanced by Berzelius. Then we had the influence or contagion theory advanced by Stahl, and subsequently taken up by Liebig. This is the theory that prevailed during my student days about 1853 and as Liebig was a representative chemist in Germany, this theory held sway during many years. His idea was that as fermentation was brought about by decomposing organic matter, such as albumen, casein, glutin, etc., it must be that the molecules of these substances were so complicated that they

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readily fell to pieces, resulting in their decomposition. The sugar molecule was very small and very stable under ordinary circumstances, but if it came in contact with the decomposing proteid it was shaken to pieces. It was a case of "evil companions corrupt good manners.” Then, of course, we had the galvanic theory and finally came the germ or vital theory. No one then thought of attributing alcoholic fermentation to yeast as a living organism. Numerous investigators took up this germ theory and it was finally established by indubitable proof. Pasteur said: “Albuminous bodies are never the ferment but the aliment of the ferment. The true ferments are living organisms.” This germ theory assumed that the yeast fed upon the sugar and broke it up into carbonic acid and alcohol and some other products. This, of course, brought yeast to the front.

Yeast was really discovered in 1680 by Anthony van Leeuwenhoeck with his new microscope. Ile describes yeast as "little globules collected into groups of three and four." It attracted at that time, of course, very little attention, and it was only at the beginning of the last century that it was taken up and the investigation was made, which showed that it was a living organism, and that fermentation was the result of its vital action. The subject attracted great attention and study spread in various directions. Some scientists carried on a warfare of words as to the possibility of the spontaneous generation of organisms. Others took up the study of disease. Other researches have led to the germ theory of diseases and the discovery of toxins, anti-toxins and immunity. It was discovered that while the greatest variety of chemical changes could be accounted for by the action of living organisms, there was fermentation which took place in the absence of a living organism. Recent investigations have disclosed that all fermentations are produced by enzymes, that the yeast produces the enzymes and that the enzymes do the work. The following is the last information that has been obtained with regard to alcoholic fermentation. After the starch has been converted by malting into maltose, the next change takes place when the yeast is added. The yeast furnishes the enzyme maltase, which converts maltose into dextro-glucose. Then another yeast enzyme, zymase, goes to the front to attack the dextro-glucose and convert it into alcohol and carbonic acid gas, but the zymase cannot accomplish this splitting alone; it requires another enzyme which is furnished by the yeast, called co-enzyme, and even the two together cannot ac

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