New York AGRICULTURAL EXPERIMENT STATION. 149 
influence of various factors upon the acetic fermentation such as 
time, temperature, the addition of vinegar and freedom from 
_ Sediment. 
Relation of time to the acetic fermentation of cider.—Tue 
following table gives the average results furnished by 10 ciders 
in relation to the formation of acetic acid from alcohol; the 
results commence with the eighth month from the time the apple 
- juice was pressed from the apples, since at this time sugar had 
disappeared and the amount of alcohol was at about its maxi- 
mum: 
Taste VIII.—Rewation or Time tro Acetic FERMENTATION OF 
ALCOHOL IN CIDER. 
Specifie Volatile acid | Fixed acid ° 
AGRE. gravity. Alcohol, aalacatia! awialie: Total acid. 
Months Per ct Per ct. Per ct. Per ct. 
See coticrrs ciara esas aia 0.9979 9 .40 0.13 .53 
2)4.3 2 eee Cie Sr 0.9984 6.15 0.59 0.10 0.69 
WO ee cra seis ares 2s 0.9993 5.67 0.90 0.06 0.96 
NAR Pca e te aa kats ohietels 1.0045 4.22 2.57 0.04 2.61 
WM eteleieins o<'se safe 1.0048 4.11 2.59 0.03 2.62 
Be S310 Clo EDIE ae Cem 1.0125 2.35 4.99 0.03 5.02 
Ara ei alle: cocks. oiCcuntaiar e 1.0185 0.88 7.01 0.03 7.04 
DMeterave sah a siete  & Sagan als 1.0187 0.64 7.07 0.02 7.09 
QONGRE Aone wae cs rt 1.0194 Tod 0.02 7.39 
OO eee Riersstws. <2 oie als 1.0252 Gals 8.38 0.02 8.40 
Tete niet cosine oes 1.0249 0.00 8.83 0.02 8.85 
Deere ayes clopa va sas Byers 3 .00 9.00 0.01 9.01 
A study of the data in this table suggests the following state- 
ments: (1) The conversion of alcohol into acetic acid took place 
slowly during the first three months after the alcohol had reached 
its maximum, that is, during the 8th, 9th and 10th months after 
the apple juice was pressed from the apples. From the 10th 
to the 14th month, the change progressed more rapidly and was 
practically completed at the end of 24 months. 
(2) Even after the disappearance of alcohol, the acid appeared 
to increase for many months. This was due to the evaporation 
of water from the vinegar cask, the remaining liquid becoming 
more concentrated. We have one instance (experiment 15) 
where the vinegar was stored in a warm place, the bung-hole of 
the cask being lightly plugged with cotton, and evaporation took 
place to such an extent that in about six years the vinegar con- 
tained over 20 per ct. of acetic acid. 
