WINE. 
910 
renders them miscible with water. These 
three principles, therefore, the oxygen, the 
hydrogen, and the carbon, are here in a kind 
of equilibrium ; and, in fact, by causing them 
to pass through a red-hot tube of glass or 
porcelain, we may re-combine them two and 
two together, and the product will be water, 
hydrogen, carbonic acid, and carbon. 
The analysis of wine commences in the 
cask, after which it successively deposits tar- 
ter, lees, and its colouring principle, till at 
length hardly any thing remains besides al- 
cohol and a small quantity of extractive mat- 
ter, dissolved in a proportion of water more 
or less abundant. But this accurate analysis, 
which exhibits to us the principles of wines in 
their separate states, throws very little light 
upon their real nature, a deficiency which we 
shall endeavour to supply by a more rigorous 
method of investigation. 
We shall distinguish in all wines an acid, 
alcohol, tartar, an extractive matter, aroma, 
and a colouring principle ; the whole being 
diluted or dissolved in a smaller or larger pro- 
portion of water. 
1. The acid. An acid exists in all wines; 
and we have never met with any in which we 
could not discover some traces of its pre- 
sence. The sweetest, as well as the most 
watery wines, impart a red tinge to blue pa- 
per that is kept for some time immersed in 
them ; but all wines are not acid' in the same 
degree. Of some wines, a natural acidity is 
the principal characteristic ; those produced 
from grapes not perfectly ripe, or that grow 
in moist climates, are of this kind; whilst such 
as are the product of the fermentation of 
grapes that have attained complete maturity 
and sweetness, contain but a very small quan- 
tity of acid. The proportion of acid appears, 
therefore, to be in the inverse ratio of the 
saccharine principle, and consequently of the 
alcohol, which is produced by the decom- 
position of the sugar. 
This acid exists in great abundance in ver- 
juice ; it is also found in must, though in less 
quantity. All fermented liquors, such as 
cyder, perry, beer, and fermented farinaceous 
substances, contain this acid in like manner. 
It is even found in melasses. Indeed, it is 
only for the purpose of completely saturating 
it, that line, ashes, and other earthy or alka- 
line bases, are used in refining sugar ; other- 
wise the presence of the acid would impede 
the cry stall zation of this salt. 
If we concentrate wine by distillation, the 
extract which remains is in general of a sour 
pungent taste. Water, or even alcohol, pour- 
ed upon this extract, will be sufficient to dis- 
solve and raise the acid. This acid has a 
slightly empyreumatic smell, leaves a bitter- 
■i ih taste in the mouth, Ac. 
This acid, well filtrated and left to stand in 
a flask, deposits a considerable quantity of 
extractive matter ; it afterwards becomes 
covered with mould, and seems to approach 
to the nature of the acetous acid ; bv dis- 
tillation it may be purified of a great quantity 
of the extractive matter, after which it be- 
comes le ss liable to be decomposed by the 
putrefactive fermentation. 
This acid precipitates the carbonic acid in 
its combinations ; it dissolves most of the 
metallic oxides with facility ; forms insoluble 
salts with lead, silver, and mercury ; and se- 
parates the metals from all their solutions by 
acids. 
This acid forms also an insoluble salt witli 
lime. When we mix a large quantity of 
lime-water with wine, the acid is precipitated 
from it, and carries with it the whole of the 
colouring principle. 
This acid, therefore, is of the nature of the 
malic acid ; it is always mixed with a small 
proportion of nitric acid ; for, if it is digested 
Upon the oxide of lead, besides the insoluble 
precipitate that is formed, a citrate is always 
produced which can be demonstrated by the 
known methods. 
This malic acid disappears when the wine 
is converted into vinegar ; it no more exists 
in well-prepared virregar than it does in the 
acetous acid. This transformation of the 
malic acid into acetous acid, affords a natural 
explanation why wine that has begun to sour 
cannot be employed in the preparation' of the 
acetite of lead; in this case an insoluble pre- 
cipitate is produced. 
The existence, in different proportions, of 
the malic acid in wine, enables us to account 
for a phenomenon of the utmost importance, 
relative to the distillation of wines, and the 
properties of the vinous spirits which result 
from this process. Every one knows, not 
only that all wines do not yield the same 
proportion of spirit, but likewise that the dis- 
tilled spirits produced from different kinds of 
wine differ very widely from each other in 
their quantities. It is also well known that 
beer, cycler, perry, and fermented farinaceous 
substances, yield but a small quantity of spirit, 
and that always of a bad quality. Careful 
and repeated distillations may indeed correct 
these faults to a certain degree, but they can 
never take them away altogether. These 
constant results, from a long course of expe- 
rience, have been attributed to the super- 
abundance of the extractive matter contained 
in these weak spirituous liquors ; the com- 
bustion of a portion of this matter, by dis- 
tillation, seemed to be the immediate con- 
sequence, and the acrid empyreumatic taste 
its natural effect. But, upon a more accurate 
investigation of this phenomenon, it is found 
that, besides the causes dependant upon the 
superabundance of the extractive principle, 
another ought to be attended to, namely, the 
presence of the malic acid in almost all" these 
cases. 
Those wines which contain the largest pro- 
portion of malic acid, afford the worst-con- 
ditioned spirit. It appears even that the 
quantity of alcohol is less in proportion as that 
of the acid is more considerable. If we se- 
parate this acid by means of lime-water, lime, 
chalk, or some fixed alkali, we can only draw 
off a very small quantity of alcohol by dis- 
tillation ; and, in every case, the spirit ac- 
quires a disagreeable fiery taste, which does 
not tend to meliorate its quality. 
The difference of the spirits obtained by 
distillation from different wines, depends, 
therefore, principally upon the different pro- 
portions in which these wines contain malic 
acid ; but no process has been hitherto dis- 
covered by which we can with certainty de- 
stroy the bad effects which the admixture of 
this acid with vinous spirits produces. 
This acid, which we find in the grape at the 
period of its growth, and which does not dis- 
appear in wines till they have completely de-. 
generated into vinegar, ought in preference 
to be denominated the vinous acid : however, 
for the sake of avoiding innovation, we shall 
retain the usual term of malic acid. 
2. Alcohoi. Alcohol forms the true cha- 
racteristic of wine. It is the product of the 
decomposition of sugar ; and its quantity is 
always proportionate to that of the sugar that 
has been decomposed. 
Alcohol abounds more in some wines than 
it does in others; those of hot climates con- 
tain a large quantity of it, whilst those of cold 
climates contain scarcely any. Ripe and sweet 
grapes produce it in abundance ; but the 
wines made of grapes that are unripe, watery, 
and sour, yield very little. 
Some wines produced in the southern parts 
of our hemisphere, yield alcohol in the pro- 
portion of one-third of their quantity ; whilst 
many of those manufactured in more northern 
latitudes contain not more than one-fifteenth. 
It is the proportion of alcohol contained in 
them that renders wines more or less gene- 
rous; and upon the same circumstance de- 
pends their disposition or resistance to the 
acetous fermentation. The less a wine con- 
tains of alcohol, the more easily it turns sour ; 
the proportion of extractive matter contained 
in it being supposed the same in both cases. 
The richer in spirit a wine is, the less it 
contains of malic acid ; and this is the reason 
; why the b£st wines, in general, furnish the 
best brandies ; as they are then exempt from 
the presence of this acid, which gives them a 
disagreeable flavour. 
It is by distillation that we extract from 
wines the whole of the alcohol they contain. 
When wines are distilled, the operation is 
carried on till the liquor which passes over is 
no longer inflammable. 
Whies furnish more or less brandy in pro- 
portion to their different degrees of spiritu- 
osity. A very generous wine furnishes about 
a third of its weight : the mean proportion of 
the brandy, furnished by the wines of the 
southern provinces of France, is about one- 
fourth of the whole ; some even yield as much 
as one-third. 
Old wines yield better brandy than new 
ones, but in less quantity, particularly when 
the decomposition of the saccharine principle 
has been- completed before they are subjected 
to the process of distillation. 
That which remains in the boiler, after 
the brandy has been extracted, is called 
vinasse ; and is a confused mixture of tartar, 
the colouring principle, lees, &c. This re- 
siduum is generally thrown away as useless: 
nevertheless, after drying it in the air, or by 
means of a stove, a tolerably pure alkali may- 
be extracted from it by combustion. 
In some distilleries the vinasse is suffered 
to turn sour, in order afterwards to distil, and 
extract the small quantity of vinegar that has 
been formed in it. 
Brandy is the more spirituous in proportion 
as it is mixed with a smaller proportion of 
water; and as it is of importance in com- 
merce, that we should be able easily to as- 
certain the degrees of spirituosity, attention 
has long been paid to the means by which 
this may be performed. 
'I he distiller judges of the spirituosity of 
brandy by the number, the magnitude, and 
the permanency, of the bubbles which form 
themselves upon agitating the liquor. With 
this view it is poured from one vessel into 
another, or suffered to fall from a certain 
height, or, which is the more general practice* 
