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Purr YEAST IN BREAD. By KATHERINE E. GOLDEN. 
Since the introduction by Hansen of pure yeast into bottom fermenta- 
tion brewing its use has spread to top fermentation brewing, to distilleries, 
and in fact, to all industries in which fermentation enters as a factor. 
This almost universal employment is due to the great benefits which 
accrue from the use of the pure culture. After methods had been devised 
for the separation of the yeasts it was determined that many which dif- 
fered from one another very slightly, if at all, morphologically, possessed 
very distinet properties when considered physiologically. This was shown 
more particularly in the by-products formed. Many yeasts which give 
practically the same alcoholic fermentation differ very materially in the 
characteristics which they impart to beer, so that it was determined that 
the flavor or “bouquet” of a beer was due primarily to the yeast; that 
by changing the yeast, keeping all the other conditions constant, a differ- 
ent beer could be produced. . ; 
The use of the pure yeast has worked to the great advantage of the 
brewer, for after a yeast has been selected and careful consideration 
given to its being kept free from foreign organisms during the brewing, 
absolute certainty is felt as to the resulting product, definite strength of 
alcohol is obtained and a constant flavor insured; moreover, the product 
can be kept indefinitely without deterioration, and can be duplicated when 
desired. It is evident that where pure yeast is used, elaborate methods 
for keeping and storing can be dispensed with, for with the absence of 
foreign organisms there is nothing present in the beer to cause it to de- 
teriorate. 
The use of the pure yeast has worked to the advantage of distillers and 
others as well as brewers, for in distilleries a greater per cent. of alcohol 
is obtained and jn the pressed-yeast factories a higher yield of yeast 
results. 
To determine whether the same advantages which have been obtained 
in other fermentation industries could not be obtained also in bread fer- 
mentation, experiments were made along this line. The experiments are 
merely outlined in this paper, no details being given. 
First, market yeasts were examined microscopically, chemically and 
in plate cultures. As a rule, the moist cakes, when taken fresh, had a 
small per cent. of dead-yeast cells, but had present many moulds and 
