June 23, 1892J 



NATURE 



\^l 



wine is tartaric acid alone. Nessler's researches have, 

 however, shown that this is seldom the case ; tartaric 

 and malic acids often exist together, and frequently the 

 free acid consists of malic acid entirely. Wines con- 

 taining tartaric acid taste more tart than those with only 

 malic acid, or a mixture of malic and tartaric acids. 



The characteristic smell of wine is said to be due to 

 cenanthic ether ; the compound ethers probably confer 

 the bouquets which distinguish one vintage from another: 

 among these are aceto-propylic, butylic, amylic, caprylic, 

 butyro-ethylic, caprylo-ethylic, capro-ethylic, and pelargo- 

 ethylic, and the tartaric ethers. According to Jacquemin, 

 these bouquets are primarily due to the special characters 

 of the yeast used in the several districts. One and the 

 same " must " fermented with the yeast obtained from 

 several different districts gave wines having the bouquet 

 characteristic of the district from which the particular 

 yeast had come. Rommer fermented the juice of an 

 inferior grape and of hot-house grapes respectively with 

 yeast cultures obtained from the Champagne, Cote d'Or, 

 and Buxy districts, and found that in each case the wines 

 had the bouquet of those from which the yeast had been 

 derived. The sugars occurring in wine are dextrose and 

 laevulose. Cane-sugar is never naturally present, even in 

 " must " ; it is sometimes added, as in the case of 

 champagne, but it is then rapidly transformed into invert 

 sugar. In some wines, as, e.g., Sauternes and sweet 

 Rhine wines, sugar occurs in the form of inosite. The 

 colouring-matter of normal wine is derived partly from 

 the oxidation of the so-called extractives contained in the 

 juice, and in the case of red wines from matter (oenolin or 

 oenotannin) contained in the husks, stalks, and seeds, 

 which is soluble only by the joint action of acid and the 

 alcohol formed during fermentation. The albuminous 

 substances in the "must" are removed when the fermen- 

 tation is properly carried out, but in imperfectly fermented 

 wines a certain amount remains, and in the case of white 

 wines may again render them liable to fresh fermenta- 

 tion. In red wines this danger is obviated by the pre- 

 sence of the tannin of the husks. 



The inorganic substances contained in wine are potash, 

 soda, lime, and magnesia, in combination mainly with 

 tartaric, phosphoric, and hydrochloric acids. Sherries 

 contain potassium sulphate in excess, owing to the 

 practice of adding gypsum to the " must." This 

 practice, which prevails not only in Spain, but also 

 in Portugal, the south of France, and to some extent 

 in Italy, probably has for its object the precipitation of 

 certain albuminous matters which injuriously affect the 

 wine. It is alleged that the fermentation is in conse- 

 quence much more rapid and complete, that the wine 

 keeps longer, and that its colour is richer and more last- 

 ing. Its real advantage to the wine-maker is that it 

 clarifies the wine rapidly, and allows it to be quickly 

 brought to market. It is chiefly employed with the 

 coarser qualities of red wine, and the gypsum is either 

 added to the grapes and trodden with them, or, in fewer 

 cases, added to the expressed juice ; the quantity 

 used is generally i to 2 kilos to every 100 kilos of 

 fruit, but it is some times as much as 10 kilos. The 

 action of the calcium sulphate on the bitartrate of 

 potash present in the juice produces an acid sulphate of 

 potash, which gradually forms the normal salt by decom- 

 NO. 1182, VOL. 46] 



position of the phosphate present forming free phosphoric 

 acid. Hence a " plastered " wine is relatively rich in 

 potash and sulphuric acid. 



Although much has been said as to the baneful effects 

 of plastered wine, very few trustworthy cases of injurious 

 action have been recorded. The Academy of Medicine 

 of Limoges instituted a lengthened inquiry on the sub- 

 ject in 1888, and reported unfavourably on the effects of 

 plastered wine upon health. The French War Depart- 

 ment also appointed a Commission, and its conclusions, 

 which, on the whole, were unfavourable to the practice, 

 have been recently confirmed by Nencki, who was re- 

 quested by the Government of the Canton Berne to report 

 on the advisabiUty of modifying a law, which operates in 

 many parts of the Continent, forbidding the sale of wines 

 containing more than 2 grams of potassium sulphate 

 to the litre. As to the question whether a plastered wine 

 should be called adulterated, it has been contended that 

 a product which, by treatment, is deprived of one of its 

 most characteristic constituents, viz. tartaric acid, whilst 

 another substance, calcium sulphate, not normally 

 present, is introduced, cannot be called anything but 

 adulterated. 



As may be supposed, the art of the falsifier is very 

 largely directed to the improvement of the colour of wine ; 

 and unfortunately it is upon the product which popular 

 prejudice associates with the name of an eminent states- 

 man, and which has no other attribute of claret than its 

 colour, that his skill is mainly expended. It has been 

 estimated that the whole yield of the " classed growths " 

 of the Mddoc does not, even in the best years, now ex- 

 ceed 5,000,000 bottles. Much of this, it is true, comes to 

 England, but enormous quantities of paysan, artisan, 

 and bourgeois wines from the Gironde and Languedoc, 

 mixed with the produce of North Spain and Italy, are 

 worked up and sold as "claret" in this country. This 

 product is not exactly poisonous, nor even, as a rule, 

 positively hurtful, but, it need hardly be said, it has no 

 special merit or individuality. Formerly, the pharma- 

 copoeia of the wine-doctor, like that of the physician of 

 old, was restricted to products of the vegetable king- 

 dom ; but, in addition to the colouring-matter of Phyto- 

 lacca berries, Althcea rosea, bilberries, mallow, elder- 

 berries, privet-berries, logwood, alkanna red, lichen reds, 

 all of which are still used to a greater or less extent, he has 

 not been unmindful of the wealth of colouring-matter 

 which is latent in coal-tar ; and to-day the banks of the 

 Rhine have their part in the manufacture of other wines 

 than hock. Biebrich scarlet, fuchsine (magenta), the 

 various Ponceaus, Bordeaux reds, crocein scarlet, and 

 similar colouring-matters, find their way to the south of 

 Europe for the purpose of wine sophistication. A sub- 

 stance known as tintura per los vinos is largely used in the 

 district of Huesca for colouring Spanish wines. It con- 

 tains two coal-tar derivatives, one of which is that form 

 of Biebrich red which is turned blue by sulphuric acid, 

 whilst the other, which exists in smaller proportion, 

 closely resembles the colouring matter known as cerise. 

 According to an analysis by Jay, the composition oi tintura 

 is : organic matter, mainly Biebrich red, 66*4 ; sodium 

 sulphate, 2610; arsenious oxide, 1*62; iron oxide, 

 lime, &c., 588. In view of the peculiar nature of this 

 substance, it is reassuring to know that there is a ten- 



