The colour of white wines is caused by the oxidation of the tannin present, but it is sometimes increased by the addition of the concentrated juice of highly-coloured grapes, or by means of a small proportion of caramel. The colour of natural red wine is due to the presence of oenocyanin, a bluish-black compound, chiefly contained in the grape skins, which is insoluble in water, but dissolves in acidulated alcohol. In Spain and southern France, a wine prepared from a vine known as the Teinturier, and possessing an intense bluish-red colour, is extensively employed for colouring of wines. There appears to be no doubt but that elderberries, black cherries, mulberries, and hollyhock are also frequently used as colouring agents. Souberian[95] mentions a mixture, termed liqueur de fismes, composed of elderberries, but also containing about 5 per cent. of alum, which is occasionally employed. The general use of several deleterious dyes, such as logwood, cochineal, and the aniline colours, is far more problematical. In regard to the last-mentioned agents, it has, however, been asserted,[96] that in a commune near Beziers, of 1800 inhabitants, magenta, to the value of 30,000 francs, is annually consumed in the adulteration of wine.

It is also worthy of remark that an aniline preparation used in Spain for the artificial colouring of wine has recently been found to contain 1·62 per cent. of arsenic acid.[97]

Owing to the ravages of the phylloxera, a very considerable decrease in the source of natural wines has taken place during the past few years. Between 1883 and 1884 no less than 22 thousand acres of vineyards were entirely destroyed in the Gironde district alone, and it is stated, upon good authority, that the total production of wines in France in 1884 was 220 millions of gallons less than the average of the previous ten years.[98] There is no doubt but that this decrease has greatly stimulated the manufacture of imitation wines. These occasionally contain a certain proportion of genuine wine as the basis, but more frequently they consist entirely of factitious constituents. The following recipe furnishes a fair example of those of the first class:—

Rousillon wine50litres.
Water85„
Common brandy20„
Vinegar1„
Tartaric acid300grammes.
Powdered orris20„
Wood charcoal500„

Agitate thoroughly, add the white of two eggs, with constant stirring; allow to settle, and draw off.

Of late years, the production of wine from dried fruit has assumed very extensive proportions in France. The product, which is generally known as “vin de raisins secs,” is claimed by its manufacturers to be wholesome.[99] A wine said to possess the qualities of a fair claret, is made by submitting to fermentation the following mixture:—

White sugar5kilos.
Raisins5„
Sodium chloride125grammes.
Tartaric acid200„
Brandy12litres.
Water95„
Gall nuts20grammes.
Brewer’s yeast200„

Another recipe for Bordeaux wine is:—

Orris root1lb.
Water5galls.
Raspberry juice1„
Pure spirit10„
Essence of claret½lb.
Sugar syrup1gall.
Colour with cochineal.

It is authentically stated that in the year 1881, 52 millions of gallons of factitious claret wine were made in France, and the industry has certainly not diminished in extent since this date. It is a significant fact that the importation of Spanish raisins into France has undergone a remarkable increase during the past few years. Nor is this species of sophistication confined to foreign wines. Establishments are in active operation in New York City and elsewhere in this country, where imitations of Californian hock and claret are made from fermented infusions of dried fruit (often charged with salicylic acid), and offered for sale at less than thirty cents per gallon, with more than the usual trade discount.[100] According to a reliable estimation, less than one-tenth of the wine sold as champagne is actually the product of that district, the remainder being fabricated from other wines or from cider.