The increasing resources of sophistication in their various legal and
illegal aspects keep pace with the progress of chemical research.
Attempts to level up the irregular work of the sun by artificial
means, so as to overcome the lack of any uniform degree of maturity
in the grape, caused by the alternating clemency and inclemency of the
vintage season, is becoming more and more common. The commonest form of
adulteration is blending, whether of separate growths or vintages. To-day
an unnamed, or vaguely named, wine, gives rise to the suspicion of being
the former, just as an undated wine carries a strong presumption of being
the latter. Happily the practice of indicating the vintages of wines
has now become much more general, and is being adopted by countries,
such as Italy, where the custom was formerly unknown. The consumer’s
best safeguard against blended wine is an estate-bottled growth.[7] The
use of chemical aids in wine-making is to some extent sanctioned by the
law. In France wine may now be sugared (_chaptalisation_), sterilised
(_pasteurisation_), fortified (_vinage_), watered (_mouillage_),
plastered (_plâtrage_), muted (_mutage_) and, in the case of white
wines, sulphured (_sulfitage_), within certain defined limits and
subject of formal declaration. The illegal adulterants of wine have been
too frequently catalogued to need any recapitulation. Synthetic scents
and flavourings are always adding to their number, but it is doubtful
whether any synthetic bouquet or taste will ever be able to deceive an
experienced palate.
_Chaptalisation_ means supplying the percentage of natural grape-sugar
which the most of wet or cold vintage years is deficient in by the
same amount of cane or beet sugar. This added sugar is converted into
alcohol at the same time, and in precisely the same way, as the natural
sugar of the fruit; thanks to this addition the wine is assured of
sufficient alcoholic body to keep, which might not otherwise be possible.
Only experts can detect a _vin chaptalisé_ from an unsugared wine.
This practice is fairly common in the northernmost vineyards, such as
Champagne, the Côte d’Or and the Moselle. The German law permits sugaring
in certain cases, but no sugared wine may be labelled “_Natur_,” or
“_Naturrein_.” Chaptalisation saved the 1925 vintage in the Bordelais,
where this expedient had hitherto been held up to execration as a
typically Burgundian falsification. _Pasteurisation_ is resorted to
so as to preserve young wines of poor vintages against attacks of
wine-maladies after they have been bottled. It allows wine to be bottled
almost as soon as made, and though it brings the wine well forward in
the process, it arrests most of its subsequent natural development.
_Vinage_ is simply, as in the case of Port, the brandying of sweet wines
with extraneous spirit. _Mouillage_ is resorted to for reducing the
alcoholic strength of common wines, which are taxed and priced at so
much the alcoholic degree. _Plâtrage_ is the sprinkling of the grapes
with plaster of paris while they are being pressed. It is supposed to be
a safeguard against the danger of secondary, or acetous, fermentation
in hot climates during the first summer following the vintage. _Mutage_
is a means of arresting fermentation chemically, so as to permit of one
wine being blended with another before allowing a joint fermentation of
the two to proceed to completion. _Sulfitage_ is used to preserve the
bright golden colour of white wines, that are apt to turn brown when
exposed to the air, and to prevent _vins liquoreux_, like Sauternes,
alcoholising a certain degree of unconverted grape-sugar, or _liqueur_,
which they are intended to retain. The old method of sulphuring was to
smoke the empty casks with sulphur matches before filling them, which
resulted in the fumes becoming amalgamated with the wine. The newer,
and more dangerous, practice is to add a small percentage of suitably
diluted Sulphur Dioxide. The French tolerance of this chemical is 450
parts per million: a proportion identical with that adopted under the new
British regulations, which define this “improver” as the only extraneous
substance that wine imported into the United Kingdom may contain.