The term wine is more strictly and especially applied to express the
fermented juice of the _Grape_, although it is generally used to denote
that of _any_ sub-acid fruit. The presence of _Tartar_ is perhaps the
circumstance by which the grape is most strongly distinguished from all
the other sub-acid fruits that have been applied to the purpose of wine
making. The juice of the grape, moreover, contains within itself all the
principles essential to vinification, in such a proportion and state of
balance as to enable it at once to undergo a regular and complete
fermentation, whereas the juices of other fruits require artificial
additions for this purpose; and the scientific application and due
adjustment of these means, constitute the art of making wines.[698] It
has been remarked, that all those wines that contain an excess of malic
acid are of a bad quality, hence the grand defect that is necessarily
inherent in the wines of this country, and which leads them to partake
of the properties of cider, for in the place of the _tartaric_, the
_malic acid_ always predominates in native fruits.
The characteristic ingredient of all wines is _Alcohol_, and the
quantity of this, and the condition or state of combination in which it
exists, are the circumstances that include all the interesting and
disputed points of medical enquiry. Daily experience convinces us that
the same quantity of alcohol, applied to the stomach under the form of
natural wine, and in a state of mixture with water, will produce very
different effects upon the body, and to an extent which it is difficult
to comprehend; it has, for instance, been demonstrated that Port,
Madeira, and Sherry, contain from one-fourth to one-fifth their bulk of
alcohol, so that a person who takes a bottle of either of them, will
thus take nearly half a pint of alcohol, or almost a pint of pure
brandy! and moreover that different wines, although of the same specific
gravity, and consequently containing the same absolute proportion of the
spirit, will be found to vary very considerably in their intoxicating
powers; no wonder then that such results should stagger the philosopher,
who is naturally unwilling to accept any tests of difference from the
nervous system, which elude the ordinary resources of analytical
chemistry; the conclusion was therefore drawn, that alcohol must
necessarily exist in wine in a far different condition from that in
which we know it in a separate state, or in other words, that its
elements only could exist in the vinous liquor, and that their union was
determined, and consequently alcohol produced, by the action of
distillation. That it was the _product_, and not the _educt_ of
distillation, was an opinion which originated with Rouelle, who asserted
that alcohol was not completely formed, until the temperature was raised
to the point of distillation; more lately the same doctrine was revived
and promulgated by Fabbroni, in the memoirs of the Florentine Academy.
Gay Lussac has, however, silenced the clamorous partisans of this
theory, by separating the alcohol by distillation at the temperature of
66° _Fah._ and by the aid of a _vacuum_, it has since been effected at
56°: besides, it has been shewn that by precipitating the colouring
matter and some of the other elements of the wine by _sub-acetate of
lead_, and then saturating the clear liquor with _sub-carbonate of
potass_, the alcohol may be completely separated without any elevation
of temperature; and by this ingenious expedient Mr. Brande has been
enabled to construct a table, exhibiting the proportions of combined
alcohol which exist in the several kinds of wine: no doubt therefore can
remain upon this subject, and the fact of the difference of effect,
produced by the same bulk of alcohol, when presented to the stomach in
different states of combination, adds another striking and instructive
illustration to those already enumerated in the course of this work, of
the extraordinary powers of chemical combination in modifying the
activity of substances upon the living system. In the present instance,
the alcohol is so combined with the extractive matter of the wine, that
it is probably incapable of exerting its full specific effects upon the
stomach, before it becomes altered in its properties, or, in other
words, _digested:_ and this view of the subject may be fairly urged in
explanation of the reason why the intoxicating effects of the same wine
are so liable to vary in degree, in the same individual, from the
peculiar state of his digestive organs at the time of its potation.[699]
Hitherto we have only spoken of _pure_ wine, but it is essential to
state that the stronger wines of Spain, Portugal, and Sicily, are
rendered remarkable in this country by the addition of _Brandy_, and
must consequently contain _uncombined_ alcohol, the proportion of which
however will not necessarily bear a ratio to the quantity added,
because, at the period of its admixture, a renewed fermentation is
produced by the scientific vintner, which will assimilate and combine a
certain portion of the foreign spirit with the wine: this manipulation,
in technical language, is called _fretting-in_. The free alcohol may,
according to the experiments of Fabbroni, be immediately separated by
saturating the vinous fluid with _sub-carbonate of potass_, while the
combined portion will remain undisturbed: in ascertaining the
fabrication and salubrity of a wine, this circumstance ought always to
constitute a leading feature in the inquiry; and the tables of Mr.
Brande would have been greatly enhanced in practical value, had the
relative proportions of _uncombined_ spirit been appreciated in his
experiments, since it is to _this_, and not to the _combined_ alcohol,
that the injurious effects of the wine are to be attributed. “It is well
known,” observes Dr. Macculloch, “that diseases of the liver are the
most common, and the most formidable of those produced by the use of
_ardent_ spirits; it is equally certain that no such disorders follow
the intemperate use of _pure_ wine, however long indulged in: to the
concealed and unwitting consumption of spirit, therefore, as contained
in the wines commonly drunk in this country, is to be attributed the
excessive prevalence of those hepatic affections which are comparatively
little known to our continental neighbours.” Thus much is certain, that
our ordinary wines contain no alcohol, but what is disarmed of its
virulence by the prophylactic energies of combination.
The odour, or _bouquet_, and flavour which distinguish one wine from
another, evidently depend upon some volatile and fugacious principle,
soluble in alcohol; this in sweet and half fermented wines, is
immediately derived from the fruit, as in those from the _Frontignan_
and _Muscat_ grapes; but in the more perfect wines, as in _Claret_,
_Hermitage_, _Rivesaltes_, and _Burgundy_, it bears no resemblance to
the natural flavour of the fruit, but is altogether the product of the
vinous process; and in some wines it arises from the introduction of
flavouring ingredients, as from almonds in Madeira wines, as well as in
those of Xeres and Saint Lucar, and hence their well known nutty
flavour. Among the ancients it was formerly, and in modern Greece it is
to this day, the fashion to give a resinous flavour, by the introduction
of Turpentine into the casks.[700] These wines are supposed to assist
digestion, to restrain ulcerous, and other morbid discharges, to provoke
urine, and to strengthen the bowels; but Dioscorides also informs us
that they were known to produce vertigo, pain in the head, and many
evils not incidental to the same quantity of vinous liquor when free
from such admixtures.[701]