This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1891 Excerpt: ...the beer unfit for consumption.-While these are considered to be mostly bacteria, it must be remembered that beer may contain a peculiar yeast, which, under suitable conditions, may so multiply as to make the beer very turbid, and affects the taste of the article. It now mostly depends what treatment the beer undergoes after leaving the brewery. In England, for instance, it is quite customary to keep the beer in the barrel until used up. In this case a slight increase of the yeast, which goes to the bottom, is not only harmless, but even desirable to keep the beer well impregnated with carbonic acid. If beer is kept in bottles, the formation of yeast ought to be only very slight, otherwise it will be almost impossible to pour out a glass of clear beer. In properly conducted breweries, it is nowadays not so particularly difficult to prevent the growth of bacteria; but if great care is not taken the brewer will be obliged to stop their multiplication by the use of some antiseptic. The process which I have now worked out to detect such adulteration is as follows: On the fifth of November last year, I received some bottles of beer, which were said to keep particularly well, and this proved indeed to be the case in a high degree. Not only was the beer still quite clear on 21 December, but even last March, after standing for four months in the laboratory, it did not show any alteration. The deposit was so small as not to sensibly render the beer turbid on shaking. On the 21st of December I started the investigation. Under the microscope, the deposit showed an organism like sarcina, also a few bacilli, but scarcely any yeast cells. A portion of this beer was now introduced, with the usual precautions, in previously sterilised Pasteur's flasks, which were only half...