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6 The Colorado Experiment Station 
apple juice would be very apt to make weak vinegar because of the 
relatively small amount of sugar present. 
This reference to sugar brings us to the third item, namely, 
the important constituents of the apple so far as cider and vinegar 
are concerned. Several years ago, Dr. Van Slyke of the Geneva, 
N. Y., Experiment Station, reported a series of analyses of apple 
juices representing eighty-three different American-grown varie¬ 
ties. He gives the average composition of these juices as follows: 
Solids .13.52 per cent 
Total sugar as invert sugar.10.91 per cent 
Ash .29 per cent 
Fixed acid (malic) .52 per cent 
The sugar is unquestionably the most important of these sub¬ 
stances so far as the part which it plays in the making of cider vin¬ 
egar since the degree of sourness due to the vinegar acid (acetic) 
is directly proportional to the fermentable sugar present; in other 
words, all of the acid which was not originally present in the cider 
as natural apple acid, or malic acid, is produced from the sugar 
by processes which are soon to be described. Therefore, since from 
a given amount of sugar just so much acid and no more can be 
made, we can understand quite readily that for a high grade vin¬ 
egar of maximum acidity the apple juice containing the most sugar 
will be the most desirable. The amount of natural acid present in 
the juice plays an insignificant part in the final acidity of the vin¬ 
egar, since the small quantity that is present in the apple juice 
practically all disappears during the change into vinegar. From 
this it is clear that it is the sugar and not the natural apple acid 
that is to be considered in cider for vinegar. 
Now, as has been stated above, cider for table use is usually 
more pleasant to drink when it is not too heavy and when the 
sugar is lower and the acid somewhat higher than the standard 
for vinegar cider requires. 
The composition of the juice of some of our common com¬ 
mercial varieties, especially the sugar content, may be of interest 
at this time in connection with what has been said with reference 
to the suitability of different ciders for vinegar making. The 
