50 CHEMICAL DISCOVERY AND INVENTION 



ing materials, are capable of seriously modifying the process of 

 fermentation. 



The study of the various forms of yeast and their associated 

 organisms led to the modern views as to the cause, progress, and 

 means of communication of many forms of disease, and laid the 

 foundation of the modern science of bacteriology. Moreover, 

 great practical advantages have arisen in enabling the brewer to 

 control the operations carried on in the brewery, which are no 

 longer empirical as in the time of little more than a generation 

 ago, but completely under the direction of well-known scientific 

 principles. 



As evidence of the importance attached by the practical man 

 to the results of Pasteur's work, mention may be made of the 

 establishment of the laboratory at Carlsberg, founded and 

 endowed in 1875, by the late J. C. Jacobsen, a well-known 

 Danish brewer. In this institution the investigations carried 

 out by Dr. E. C. Hansen led to the adoption of a system of pure 

 yeast culture, which has found its way into many continental 

 breweries. After trial in each brewery to find out which variety 

 of yeast suits best the local conditions and furnishes most satis- 

 factorily the quality of beer required, the process begins in the 

 laboratory by isolating a single cell, under proper conditions to 

 avoid contamination, and from this by allowing it to produce 

 other cells by budding, a larger number of parent cells are 

 generated, and these again in successive generations produce a 

 sufficient crop for practical use in the brewery, where further 

 cultivation can be carried on and a sufficient quantity of yeast 

 obtained for any quantity of wort. 



The use of a brewing school therefore is to supply instruction 

 first of all in the scientific principles of physics, chemistry, and 

 biology sufficient to enable the student to understand the applica- 

 tion of this kind of knowledge to the problems connected with 

 fermentation. It has to be remembered that alcoholic fermenta- 

 tion is not the only kind of chemical change to which saccharine 

 solutions are liable in the presence of micro-organisms. The 

 student must learn to recognise and distinguish those which 

 produce acetic, lactic, and other acids, and those which give rise 

 to other morbid conditions of beer, such as turbidity or disagree- 

 able flavours. He must also make himself familiar with all the 

 different varieties of carbohydrate, the sugars, starches, dextrins, 

 which occur in brewing materials. He must know the influence 



