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146 Report OF THE CHEMIST OF THE 
In connection with the data in this table, attention is called 
to the following points: 
(1) The sucrose disappeared more rapidly than the reducing 
sugars. The former had been practically all changed in five 
months, while the latter were not completely gone in seven months. 
It should be stated here that sucrose as such does not undergo 
fermentation but it must first be changed into dextrose and 
levulose. This change is affected by an enzym which exists in 
yeast. The dextrose and levulose thus formed from sucrose are 
readily acted upon by the alcholic-producing ferment of the yeast. 
Taking the total amount of sugar in the fresh apple juice, we 
find that it disappeared at a rate expressed by the following 
figures : 
In 1 month, 7.1 per cent. In 5 months 94.3 per cent. 
In 2 months, 38.7 per cent. In 6 months, 97.6 per cent. 
In 3 months, 68.4 per cent. In 7 months, 98.3 per cent. 
In 4 months, < 81.0 per cent. 
Thus, we see, a large proportion of the sugar had been ehanged 
by fermentation in five months under the given conditions. 
(2) The alcohol increased quite rapidly after the first month, 
and approximately in proportion to the amount of sugar that 
disappeared. The amount of alcohol reached its highest point 
at the end of six months, when the sugar had practically all 
gone. ; 
(8) The specific gravity of the fermenting apple juice decreased 
as the amount of sugar decreased and the amount of alcohol 
increased, going from 1.064 in the fresh apple juice to 0.9986 at 
the end of seven months. 
Influence of temperature upon the alcoholic fermentation of 
apple juice.—Samples of cider were placed in rooms, the tempera- 
ture in each of which is kept practically constant. The tempera- 
tures used were 55°, 60°, 65°, 70° and 85° F. (experiments 
numbered 17, 18, 19, 20 and 21). In other experiments, casks of 
cider were placed in a celler (experiments 11, 12, 18, 14), the 
temperatures of which during the time of study varied from about 
45° to 55° F. while other casks were placed in a room near a steam 
boiler, the temperature here varying from about 70° to 80° F. 
(experiments 15 and 16). The following table contains the 
results given at the time when the sugar had nearly all disap- 
peared in most of the ciders: 
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