VINEGAR-MAKING 237 
whole. Its action causes the alcohol to unite with oxygen from 
the air, thus producing acetic acid. The bacteria in this method 
grow chiefly on the surface of the liquid, and they develop luxuri- 
antly during the process. The oxidation does not always stop 
at the formation of acetic acid, but is sometimes carried further 
so as to split up the alcohol into simpler molecules. This results 
in a loss, and is one of the difficulties to be met with in the manu- 
facture of vinegar. This loss, though sometimes considerable, 
is generally not great, for the accumulation of acetic acid will 
soon stop the growth of the organisms. Different species of the 
organisms can endure different amounts, but when the acetic 
acid has reached 14 per cent. the bacteria are never able to 
produce any more. 
The Quick Process--A second process of vinegar-making, 
known as the “quick process,” does not, at first sight, appear 
to be caused by microdrganisms. This process consists simply in 
an intimate mixture of alcohol with air by means of shavings. 
A mass of shavings is placed in tall vessels and thoroughly mois- 
tened with an alcoholic solution. Then the whole is inoculated 
with a little warm vinegar followed by alcohol. The vinegar thus 
added starts the process, and in a few hours new vinegar is pro- 
duced. Alcohol is now added at the top, slowly but continuously, 
and it percolates through the shavings and appears at the bottom 
as vinegar. Such a process seems at first to be more like a 
chemical phenomenon than a fermentation induced by micro- 
Grganisms. But it does not start until a little warm vinegar 
has been added to the mixture, and such vinegar will be sure to 
contain bacteria. This, of course, suggests that the micro- 
érganisms, thus added, spread through the shavings, grow rapidly, 
and soon induce the oxidation. Indeed, it has been proved that, 
if the growth of the fungi is prevented in such a mixture, no 
vinegar is formed. The shavings simply furnish a large surface 
for the spreading out of the organisms. Hence, the quick vinegar 
process is also dependent upon the presence and active growth of 
the vinegar plants. 
