Fermenta- 
tion. 
» at aaa 
wT 
yaw or unmalted state. The process, in that case, is 
_ conducted more rapidly, and allowed to proceed to its 
vi iho Sherchnory of the ‘chentiell Aldiiges 
» With to the ical ¢ 
which the vinous ae The tabject have 
no precise know : su in- 
vestigated by Lavoisier ; ne ‘hough he was the first 
who gave. any thing like an accurate account of the 
process, the conclusions which he deduced from his ex- 
periments, are by no means free from objections. He 
dissolved sine of pure sugar in water, and caused 
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process ; which is to , as little more 
a art meee i To this it may be 
added, that’ contains less oxygen than sugar. 
Upon the'whole, the hypothesis of i ia pechape 
less probable than that of Thenard ; in 
sent state of our knowledge on this subject, it would be 
FERMENTATION. «9% 
303 
is Completed ; and: more especially if the fermentative 
principle has been used in excess. Hence, after the 
termination of the latter, the fermentation is usually 
by decanting the clear wine from the lees, cla- 
Fermenta- 
tion. 
rifying it with isinglass, corking it up carefully, and _ 
placing it in a cool situation’ where it may remain un- — 
By these processes, the yeast, which may 
“still exist in excess in the vinous product, is almost en- 
tirely removed, and thus the fermented liquor is not 
exposed to any decomposition from the reaction of its 
own elements. 3 ii? it ; 
The acetous fermentation is not confined to the pro- 
ducts of the vinous stage; for it appears, that some 
substances not su ible of vinous. fermentation, as 
fecula and sey ve an ascescent tendency ; but 
ve passed through that process, as 
wines, cider, beer, &c. are most susceptible of spon- 
taneous acetification, and the richest and most generous 
wines furnish the best and strongest vinegar. 
The vinous liquors do not readily undergo the ace- 
tous fermentation without the assistance of some fer- 
mentative principle; and hence, on converting wines 
into vinegar, a quantity of that substance, in some form 
- ere a-omaliy ee It in Sn ai Tray Sat 
lees of vinegar, and casks i with it, ide 
presence of air is no less | to the acetous 
fermentation, Wines well corked in bottles, and grapes 
pengerty closed up in casks, may be preserved a very 
pty dig without suffering much chan 
ed 
Substances 
susceptible 
of the pro- 
cess. 
The pre- 
sence of air 
necessary. 
; but if the. 
imperfectly excluded, they are gradually render- 
ish, and in a greater degree, the more free- 
ly the air is admitted. Saussure states, that in this case 
oxygen of the air enters into combination with the 
carbon of the vinous.liquor, and abstracts that element 
from it in the form of carbonic acid. . It is. probable, 
however, that a portion of it also combines with the 
same substance, and contributes to the production of 
the acetic acid which is forn 
The acetous fermentation on when the tempera- 
ture is below, 60°, but it is slow ; and ce 
has proved, that the adyances best when the 
temperature is between. 70° and 75° of Fahrenheit’s 
scale, In manufactories for making vinegar, the heat 
is kept up at this pitch by ial means, when the 
temperature of the air is too low. 
A sli itation, repeated at intervals, is extremel 
Ore one cas eer ae 
which are to contin i 
by any powerful mechanical instrument, sein eae: 
cei eae : Lby the 
catTiages, are very unfit for vinous liquors. 
By the agitation Ui ehich ‘eine is in such cases expo- 
sed, the tartar, the lees, the extractive principle, and all 
fhe ee substances which it its ms state of rest, 
ing rate incessantly as so man 
ferments, and mag depuration Which might 
otherwise take Hence the acetous fermentation 
is greatly promoted by, frequently stirring the liquor. 
gs: to its.action.. ; 
» general appearances. which present themselves 
in the acetous fermentation, differ but little from those 
Tempera- 
ture best 
suited to the 
process. 
Effects of 
agitation, 
frequent rolling of heavy , 
Phenomena 
attending 
in the vinous, A tremulous movement pervades the the acetous 
whole mass ; 
i tof carbonic acid than in the vinous stage 
of the process. The temperature rises, and if the quan- 
ity of liquor be considerable, sometimes reaches 90° of 
F heit’s scale. In the mean time a kind of fila- 
but this is attended with a less copious fermenta- 
tion, 
ments. or streaks are moving continually in the heart of. 
