144 ReEporT OF THE CHEMIST OF THE 
example, the sample of Red Astrachan apple juice contains 10.16 
per ct. of sugars and 1.15 per ct. of malic acid, while Tolman 
Sweet and Sweet Bough contain about the same amount of sugar 
but only 0.10 to 0.20 per ct. of malic acid. We have noticed 
the same fact in studying the composition of other fruits, especi- 
ally strawberries. 
THE ALCOHOLIC FERMENTATION OF APPLE JUICE. 
When apple juice is left exposed to the air, it is gradually 
changed, losing its sweet taste and giving off bubbles of gas more 
or less vigorously. The most prominent change is the conver: 
sion of the sugars into alcohol and carbon dioxide gas, as 
expressed appropriately by the following general equation :— 
Sugar Aleohol Carbon Dioxide 
CeHi2 Oe=2 C2 He O+2 C Oz 
Alcoholic fermentation is caused by a vegetable ferment or 
enzym which is produced by ordinary yeast. Cells of the yeast 
plant are so widely distributed that they get into the apple juice 
abundantly under ordinary conditions. 
Theoretically, we should be able to get from 100 parts of sugar 
about 15 parts of alcohol and 49 parts of carbon dioxide. In 
actual practice we are not able to obtain this amount of alcohol, 
because, under the conditions employed, some of the alcohol is 
lost by evaporation and some is lost by certain changes that 
accompany alcoholic fermentation. Our work was not conducted 
in such a way as to determine accurately the amount of alcohol 
formed in apple juice from a given amount of sugar; but, accord- 
ing to some very satisfactory work on this point done by °"Browne, 
we may obtain in the fermentation of apple juice 45 to 47 parts 
of alcohol from 100 parts of sugar. 
In no case did we find alcohol in freshly expressed apple juice, 
when we used only sound fruit. 
MANAGEMENT OF ALCOHOLIC FERMENTATION. 
‘After the juice was pressed from the apples, it was, in the case 
of our first experiments, including those numbered 1 to 10, 
strained through linen cheese-cloth and placed in 10-gallon casks. 
The casks were placed in a cellar, where the temperature ran 
'Annual Report of the Pennsylvania Department of Agriculture, 1899, 
p- 556, and 1901, p. 136. 
