WHAT IS WINE? 
359 
Besides this ethylic alcohol, small quantities of some of its 
higher homologues, as propylic, butylic, amylic, alcohol, &c., as 
well as some of the fatty acid series, will likewise have been 
formed from the sugar ; whilst a part of the ethylic alcohol will 
have been converted into acetic acid. At the same time the 
alcohol produced will have dissolved several substances from 
the skins and seeds, such as colouring matter and fat, the latter 
being thus brought within the oxydising influence of the 
atmospheric air. On the other hand, some substances pre- 
viously in solution will have been thrown down as being less 
soluble in a spirituous liquor than in water, such as the bi- 
tartarate of potassium: the wine contains consequently less 
fixed acid than the must Part of the alcohol, however, 
becoming oxydised into acetic acid, the sum total of free acid 
in the wine is not much less than it is in the must The 
albuminous substances and mucilage have also in great part 
disappeared, partly by having been absorbed by the ferment, 
and separated in an insoluble condition with the yeast, partly 
by being oxydised into fatty acids, or changed into extractive 
matters, or, lastly, by being precipitated by the tannin. 
Meanwhile the various substances thus produced have not 
been without chemical action on each other ; the most important 
result of which is the production of a number of compound 
ethers * by the mutual action of the various acids on the several 
alcohols present. To these compound ethers, together with the 
ferment oils previously mentioned, the wine owes in great 
measure its smell and bouquet. This first fermentation usually 
lasts fromt two to six weeks ; after which the wine is left on the 
lees till the following spring, and is then drawn off into a fresh 
cask, in which a slight secondary fermentation continues, some- 
times for years ; the wine being repeatedly during this time 
drawn off from the sediment it deposits. During this secondary 
fermentation the removal of sugar is completed, the albumen 
is also either precipitated or oxydised, and a slight deposition 
of tartar continues ; whilst more of the alcohol is converted 
into acetic acid, and, in red wines, much of the colouring 
means of which arrangement the temperature is kept as low as 6° C. during 
the entire summer. 
* A compound ether may he considered as a combination of the acid 
with the alcohol, minus one atom of water. Thus : — 
, alcohol 
acetic acid . 
, , .minus water 
acetic ether . 
. C,H,0 
OAA 
HjO 
C.H3O, 
