FERMENTATION : APPLE JUICE | TANNIN. 
139 
closed, to place all the vessels and implements used there, and then to fumigate it altogether by 
burning sulphur within it, and thus destroy any germs of injurious fermentation that may exist 
from previous operations. 
Composition of the Fresh Juice. —An analysis of the exact composition of the fruit of 
the Pear has already been given (see page 128). The Chemists appointed by the French Congress 
for the study of Cider fruits have given the following analysis of Fresh Apple Juice, as the mean 
.of many examinations of juice from the best varieties of fruit; their density varying from 1067 to 
1080. 
One Thousand Parts of Juice contained : 
Water 
Sugar capable of being converted to Alcohol 
Tannic Acid, or Tannin 
♦ Mucilage, or pectosine (soluble pectine, gum) 
Free Acids (Malic, Tartaric, (&c.) 
Albumen and Fermentable Matter 
Saline Matters (Lime, Mallates of Potash and of Lime, Phosphate of Lime) 
Pectic Acid, Coloring Matter, Fixed and Volatile Oils, and Insoluble Substances in suspension 
800 
i73 
5 
12 
1.07 
5 
r *75 
2.18 
They found the juice from inferior fruits contained the same materials, but in very different pro¬ 
portions, with the exception of the Albumen, Fermentable Matter, and the Salts of Potash and 
Lime, which were in much the same proportions in all qualities of juice. These inferior juices, 
having a low density, had one-third less of sugar ; the Tannin was only 1 part instead of from 4 to 
6 ; and the amount of Mucilage was only 4 instead of 12 parts in a thousand.—“ Le Cidre ,” p. 111. 
From an examination and comparison of the best Cider fruits of France, England, Germany, 
and America, the Congress states that the general characters they should possess are, good Perfume, 
slight Bitterness, and very little Acidity, with a notable quantity of Tannin and of Mucilage, and a very 
large amount of Sugar. Sugar, and the Alcohol formed from it, are the most important elements of 
Cider, and the best varieties of fruit are essentially necessary for their production in sufficient 
quantity to enable it to travel without injury. The best and soundest Cider should contain from 
8 to 10 per cent, of Alcohol, (the French say 12 per cent) ; with from 2 to 3 per cent, of sugar still 
unreduced, to give it the highest commercial value. 
M. Pasteur gives as the result of many analyses that 100 parts of the Sugar of fruits capable 
of being convertible into Alcohol yield : 
Carbonic Acid 
Alcohol ... 
Glycerine 
Succinic Acid 
Matter yielded to the ferment 
46.67 
48-46 
3-23 
0.61 
1.03 
Tannin , or Tannic Acid\ is the next most important element in the fresh juice. It makes 
the liquor “fine” more readily by causing the Albumen, the Pectine, and the Yeast Plants to be 
deposited ; and thus acts indirectly as an antiseptic, regulates the action of fermentation, and 
prevents the after tendency to ropiness, so apt to appear in the liquor from fruits of great richness. 
