SUGAR AND ACID IN GRAPES DURING RIPENING. 21 
Table 3. — Comparison of sugar and acid elements in Catawba fruit, 1911-12. 
Tartaric acid. 
Dates when 
Sugar. 
Total acid. 
Fixed acids 
other than 
tartaric. 
Cream of 
sampled. 
Total. 
Free. 
tartar. 
1911 
1912 
1911 
1912 
1911 
1912 
1911 1912 
1911 
1912 
1911 
1912 
1911 
1912 
Aug. 20 
Sept. 9 
7.22 
6.68 
3.35 
3.02 
0.98 1 
08 
0.22 
0.65 
2.75 
2.16 
0.75 
0.41 
Aug. 23 
Sept. 12 
9.46 
9.35 
2.96 
2.48 
1.01 
90 
.22 
.45 
2.35 
1.80 
.80 
.46 
Aug. 27 
Sept. 17 
11.58 
10.38 
2.21 
2.12 
.79 
90 
.15 
.47 
1.74 
1.44 
.65 
.45 
Aug. 30 
Sept. 24 
12.32 
11.33 
1.98 
1.74 
.74 
73 
.08 
.20 
1.57 
1 28 
.67 
.53 
Sept. 3 
Oct. 1 
15.24 
12.75 
1.50 
1.63 
.59 
80 
.05 
.31 
1.18 
1.07 
.53 
.54 
Sept. 6 
Oct. 7 
16.08 
13.79 
1.28 
1.53 
.53 
so 
.03 
.23 
1.00 
1.02 
.48 
.61 
Sept. 10 
Oct. 16 
16.28 
15.35 
1.19 
1.34 
.57 
78 
.19 
.23 
.81 
.83 
.37 
.61 
Sept. 13 
Oct. 23 
17.28 
15.01 
1.12 
1.28 
.60 
64 
.08 
.08 
.78 
.91 
.50 
.59 
Sept. 20 
Oct. 29 
19.44 
16.49 
.99 
1.22 
.48 
75 
.00 
.23 
.73 
.73 
.53 
.57 
Sept. 27 
Nov. 4 
19.94 
16.77 
.89 
1.28 
.50 
S4 
.00 
.23 
.63 
.74 
.53 
.71 
Oct. 4 
Nov. 8 
19.45 
16.39 
.95 
1.09 
.58 
79 
.04 
.29 
.64 
.55 
.56 
.52 
The crop of 1911 was of excellent quality for wine making pur- 
poses, while that of 1912 was distinctly poor, yet the sugar content 
varies only about 3 grams at the final examinations given in Table 3. 
This result agrees with our study of general crop samples in good 
and poor crop years, as shown in Bureau of Chemistry Bulletin 145. 
The acid elements are more difficult and complex as to comparison. 
In total acid the crop of 1911 exceeds that of 1912 for the first several 
samples compared, but gradually declines until it falls below the 
latter. The final difference, however, is not marked. The fact 
that free tartaric acid in appreciable quantity continues present in 
the 1912 crop is important from a manufacturing point of view, 
because this acid can not be eliminated from the products except 
by the artificial introduction of a base such as potassium or calcium. 
The fixed acids other than tartaric (malic) are interesting in that 
for the good crop year (1911) the values obtained in the early stages 
were much greater than in 1912, while at the end of the season the 
two crops were about alike. The total tartaric acid of the poor 
crop (1912) sensibly exceeded that of the 1911 crop and the free tar- 
taric acid markedly exceeded that found in 1911 in the early samples 
and at the time of harvesting still maintained this excess. 
The remarks on the analytical results for cream of tartar given 
under "Crop of 1911" apply to the consideration of the results 
obtained for the juice samples analyzed in 1912. The juice samples 
of 1912 also show exceptions which, though not so marked, are 
noticeable. The varieties sampled in 1912 show, with one exception, 
an increase of cream of tartar as the fruit matured, whereas in 1911 
the samples are not uniform in this regard. This lack of logical 
results in regard to the content of cream of tartar, and also other 
considerations, led us to examine whole fruit samples in 1912. The 
fruit sample was treated in such manner that the entire content, of 
