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 varieties. 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 substances so far as the part which it plays in the making of cider vinegar 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 vinegar 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 vinegar, 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 commercial 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 [Page 7] analyses which I am submitting are those given by Dr. Van Slyke* for eastern apples. *Van Slyke, L, L., Bulletin 258, Geneva, N, Y., Exp. Sta. "A Study of the Chemistry of Home-Made Cider Vinegar," 1904.