Generally described, these consist in producing an imitation of the natural salinity of the dry wine by the addition of factitious salts and fortifying with alcohol. The sugar remains, but is disguised thereby. It was a wine thus treated that first brought the subject of the sulphates, already referred to, under my notice. It contained a considerable quantity of sugar, but was not perceptibly sweet. It was very strong and decidedly acid; contained free sulphuric acid and alum, which, as all who have tasted it know, gives a peculiar sense of dryness to the palate.
The sulphuring, plastering, and use of Spanish earth increase the dryness of a given wine by adding mineral acid and mineral salts. In a paper recently read before the French Academy by L. Magnier de la Source (‘Comptes Rendus,’ vol. xcviii. page 110), the author states that ‘plastering modifies the chemical characters of the colouring matter of the wine, and not only does the calcium sulphate decompose the potassium hydrogen tartrate (cream of tartar), with formation of calcium tartrate, potassium sulphate, and free tartaric acid, but it also decomposes the neutral organic compounds of potassium which exist in the juice of the grape.’ I quote from abstract in ‘Journal of the Chemical Society’ of May 1884.
In the French ‘Journal of Pharmaceutical Chemistry,’ vol. vi. pp. 118-123 (1882), is a paper, by P. Carles, in which the chemical and hygienic results of plastering are discussed. His general conclusion is, that the use of gypsum in clearing wines ‘renders them hurtful as beverages;’ that the gypsum acts ‘on the potassium bitartrate in the juice of the grape, forming calcium tartrate, tartaric acid, and potassium sulphate, a large proportion of the last two bodies remaining in the wine.’ Unplastered wines contain about two grammes of free acid per litre; after plastering, they contain ‘double or treble that amount, and even more.’
A German chemist, Griessmayer, and more recently another, Kaiser, have also studied this subject, and arrive at similar conclusions. Kaiser analysed wines which were plastered by adding gypsum to the must, that is to the juice before fermentation, and also samples in which the gypsum was added to the ‘finished wine,’ i.e. for fining, so-called. He found that ‘in the finished wine, by the addition of gypsum, the tartaric acid is replaced by sulphuric acid, and there is a perceptible increase in the calcium; the other constituents remain unaltered.’ His conclusion is that the plastering of wine should be called adulteration, and treated accordingly, on the ground that the article in question is thereby deprived of its characteristic constituents, and others, not normally present, are introduced. This refers more especially to the plastering or gypsum fining of finished wines. (Biedermann’s ‘Centralblatt,’ 1881, pp. 632, 633.)
In the paper above named, by P. Carles, we are told that ‘owing to the injurious nature of the impurities of plastered wines, endeavours have been made to free them from these by a method called “deplastering,” but the remedy proves worse than the defect.’ The samples analysed by Carles contained barium salts, barium chloride having been used to remove the sulphuric acid. In some cases excess of the barium salt was found in the wine, and in others barium sulphate was held in suspension.
Closely following the abstract of this paper, in the ‘Journal of the Chemical Society,’ is another from the French ‘Journal of Pharmaceutical Chemistry,’ vol. v. pp. 581-3, to which I now refer, by the way, for the instruction of claret-drinkers, who may not be aware of the fact that the phylloxera destroyed all the claret grapes in certain districts of France, without stopping the manufacture or diminishing the export of claret itself. In this paper, by J. Lefort, we are told, as a matter of course, that ‘owing to the ravages of the phylloxera among the vines, substitutes for grape-juice are being introduced for the manufacture of wines; of these, the author specially condemns the use of beet-root sugar, since, during its fermentation, besides ethyl alcohol and aldehyde, it yields propyl, butyl, and amyl alcohols, which have been shown by Dujardin and Audigé to act as poisons in very small quantities.’
In connection with this subject I may add that the French Government carefully protects its own citizens by rigid inspection and analysis of the wines offered for sale to French wine-drinkers; but does not feel bound to expend its funds and energies in hampering commerce by severe examination of the wines that are exported to ‘John Bull et son Île,’ especially as John Bull is known to have a robust constitution. Thus, vast quantities of brilliantly coloured liquid, flavoured with orris root, which would not be allowed to pass the barriers of Paris, but must go somewhere, is drunk in England at a cost of four times as much as the Frenchman pays for genuine grape-wine. The coloured concoction being brighter, skilfully cooked, and duly labelled to imitate the products of real or imaginary celebrated vineyards, is preferred by the English gourmet to anything that can be made from simple grape-juice.
I should add that a character somewhat similar to that of natural dryness is obtained by mixing with the grape-juice wine a secondary product, obtained by adding water to the marc (i.e. the residue of skins, &c., that remains after pressing out the must or juice); a minimum of sugar is dissolved in the water, and this liquor is fermented. The skins and seeds contain much tannic acid or astringent matter, and this roughness imposes upon many wine-drinkers, provided the price charged for the wine thus cheapened be sufficiently high.
Some years ago, while resident in Birmingham, an enterprising manufacturing druggist consulted me on a practical difficulty which he was unable to solve. He had succeeded in producing a very fine claret (Château Digbeth, let us call it) by duly fortifying with silent spirit a solution of cream of tartar, and flavouring this with a small quantity of orris root. Tasted in the dark it was all that could be desired for introducing a new industry to Birmingham; but the wine was white, and every colouring material that he had tried producing the required tint marred the flavour and bouquet of the pure Château Digbeth. He might have used one of the magenta dyes, but as these were prepared by boiling aniline over dry arsenic acid, and my Birmingham friend was burdened with a conscience, he refrained from thus applying one of the recent triumphs of chemical science.
This was previous to the invasion of France by the phylloxera. During the early period of that visitation, French enterprise being more powerfully stimulated and less scrupulous than that of Birmingham, made use of the aniline dyes for colouring spurious claret to such an extent that the French Government interfered, and a special test paper named Œnokrine was invented by MM. Lainville and Roy, and sold in Paris for the purpose of detecting falsely-coloured wines.