To secure the highest attainable degree of maturity in the grapes, the vintage on the Rhine is postponed until the grapes almost begin to wither, and the white grapes on the sunny side of the bunches exhibit a yellowish brown (instead of a green) colour and show signs of flaccidity. In the best vineyards (where it is worth the trouble) the bunches are carefully sorted, the ripest being put aside and pressed by themselves. In some places even the individual bunches are analysed and the best berries cut out with a pair of scissors, to be used by themselves. The processes concerned in the extraction of the juice are described below (p. 605). If the production of red wine is intended, the juice is allowed to ferment over the stalks and skins until enough of alcohol has been produced to enable the juice to extract the pigment from the skins. After that juice and residue are separated. The alcohol, however, extracts other things besides the pigment, especially tannin, which imparts to red wines their characteristic astringency. The must (or magma of crushed grapes) is immediately conveyed to a cool cellar, the temperature of which should lie between 9° and 12° C., and is placed in large tubs or vats or open casks, and is then left to itself. Although no yeast is added from without, vinous fermentation sets in sooner or later, and after some four to five days is in full swing. On the seventh day, as a rule, the process has passed its climax, and after ten to fourteen days the yeast-scum on the surface disappears and the liquid clears up. It now constitutes what is called Jungwein, which still contains a considerable remnant of unfermented sugar. This young wine is drawn off into large casks and placed in cellars having a temperature of 9° to 12° C.; there it is left for some months, generally until the following March. The casks are filled almost to the bung-hole and kept full by the occasional addition of wine, the small bung-hole being covered so as to provide an outlet for the carbonic acid, without giving any greater access to the air than is absolutely unavoidable, to prevent acetous fermentation. During this period the small remnant of sugar in the young wine gradually ferments away, while the percentage of alcohol undergoes a corresponding gradual increase. As this after-fermentation progresses very slowly, there is no perceptible increase of temperature in the liquid, and even the newly-formed yeast cells remain deposited at the bottom as a precipitate. On it certain components of the must, being less soluble in (alcoholic) wine than in the must, separate out, as, for instance, the albumenoids and, most markedly, the bitartrate of potash; this last separates out conjointly with tartrate of lime and colouring-matters, as a coherent crust known as argol. The finished young wine is drawn off clear into smaller casks, bunged up, and allowed to mature. It is during this period that the “bloom” of the wine develops, probably through the very slow formation of ethers from the alcohol and the acids previously produced, or from traces of higher alcohols by oxidation. How long a wine should be allowed to mature depends on its richness. With relatively poor wines a year’s maturing may be amply sufficient; rich wines continue improving for years.

To give an idea of the composition of grape juice, we quote two analyses of high-class musts of 1868, by Neubauer;— [table]

Supposing such musts to ferment, the albumenoids are partly precipitated as components of the yeast or otherwise, or decomposed, with formation of ammonia salt; part of the phosphates go into the yeast likewise; the greater part of the bitartrate of potash of the juice is precipitated as argol; and the greater part, if not all, of the sugar is decomposed, with formation from every 100 parts of sugar destroyed of alcohol 48 ’ 5, carbonic acid 46 - 9, succinic acid 0 ’ 7, glycerin 3Ό, matter passing into the yeast 0 - 9 as principal products.

Besides the predominating process of vinous fermentation proper, certain minor fermentations and other byereactions take place, which lead to the formation of free acetic and other fatty acids, ethers, and traces of higher alcohols. Of these last, however, which play such an important part in whisky-brewing, only very little is formed in grape-juice fermentation. Of the bye-products the ethers are undoubtedly the most important, because it is they that constitute the bloom; but our knowledge regarding them is very limited. The flavour of a wine is due to two sets of volatile bodies, namely—(i.) aenanthic ether (see Oenanthic Acid, vol. xvii. p. 731), to which is due the smell common to all wines (which remains in an empty wine cask after the bloom proper has gone), and (ii.) a set of ethers (are they ethers 1) which constitute the Blume. Geiger distilled a bottle of good wine and then re-mixed residue and distillate. But the mixture was not drinkable; yet, after having been bottled up for a long time, it gradually regained its original virtues. These remarks apply only to white Rhenish wines. Red wines, in addition to the components named, contain chiefly colouring and astringent matters. The wines of Hungary, France, &c., as is well known, have a different character from those of the Rhine region; but the scientific analysis of the relations is of comparatively little importance.

In all rich musts part of the sugar escapes fermentation and imparts to the wine a higher or lower degree of sweetness; southern wines (port, sherry, &c.), even in their natural condition, contain relatively large percentages of sugar. In their case it is chiefly this sugar, in Rhine wine the glycerin and what there may be of unchanged sugar, which constitute the “body” of the wine. Spanish and Portuguese wines, however, especially those intended for exportation into Great Britain, are habitually doctored by the addition of cane sugar and cognac.

Wine-Brewing.— One mode of assisting nature in winemaking is the process of “gallisizing,” so called from its inventor (Gall), which is largely practised on the Rhine. In a given vineyard the must produced in a good year is characterized by certain percentages of free acid and of sugar. In bad years the latter decreases and the former increases. But this, according to Gall, can be easily remedied by adding sugar and water in sufficient quantity to establish the percentages of free acid and sugar which are characteristic of the best years, and then allowing the mixture to ferment. The sugar is added sometimes in the form of cane sugar (which is no doubt the best substitute for natural grape sugar obtainable), but more frequently in the form of what is known in commerce as “grape sugar,” which is in reality more or less impure dextrose produced from potatoes or maize starch (see Sugar, vol. xxii. p. 623). Scientifically speaking, Gall’s method appears to be unobjectionable; but that it does so is really owing to our ignorance of the intricacies of the actual process of grapejuice fermentation. In any case, grape juice is one thing and dextrose plus so much pump-water is another; and the sale of gallisized as “natural” wine must be pronounced a fraud. Science affords a means of distinguishing a gallisized from a natural wine, if the added sugar consisted of dextrose. The sugar of normal grape juice is half dextrose and half laevulose; a similar mixture is produced from added cane sugar. In the process of fermentation the dextrose is the first to disappear; the rest of the laevulose then follows. Hence a finished natural wine, if it turns the plane of polarized light at all, will turn it to the left; but, if the wine was doctored with dextrose, certain dextro-rotatory impurities survive to the end and the wine turns the plane of polarization to the right (Neubauer). A commission of experts who met in Berlin in 1884 declared gallisizing to be a legitimate practice as long as the water added does not amount to more than twice the weight of the added sugar. Liebig long ago recommended the addition of a concentrated solution of neutral tartrate of potash to ready-made wine, as a means for reducing its acidity. If the free acid is tartaric, it combines with the tartrate into cream of tartar, which gradually separates out and can be removed by decantation or filtration. Long before Gall, Chaptal showed that bad must may be improved by adding the calculated weight of (cane) sugar and neutralizing the excessive acid by means of powdered marble. The principal feature in Chaptal’s, as compared with Gall’s method, is that it discards the resources of the pump.

In Spain, Portugal, and France it is a very common practice to dust over the grapes with plaster of Paris or to add the plaster to the must. The intention is, in the former case, to prevent putrefaction of the berries, in the latter to add to the chemical stability of the wine. According to experience, a plastered wine is ready for bottling sooner than it would be in its natural condition. The chemical process involved consists in this: the sulphate of lime, CaSO 4 , decomposes the bitartrate of potash, (C 4 H 4 O 6 ) KH, of the must, with the formation of insoluble tartrate of lime, (C 4 H 4 O 6 )Ca, and soluble acid sulphate of potash, KHSO 4 . The latter takes up potash from, chiefly, the phosphate present and becomes normal salt, K 2 SO 4 , with the formation of free acid (e.g., phosphoric acid). A plastered wine is relatively rich in potash and in sulphuric acid. Amongst German wine-analysts it is customary to report all the sulphuric acid found as sulphate of potash, K 2 SO 4 . If the calculated sulphate amounts to less than 2 grammes per litre, the wine is passed as being at any rate not excessively plastered. But the interpretation of a sulphuric acid determination, in the case of German wines more especially, is rendered very uncertain owing to the widely spread practice that prevails of disinfecting winecasks with sulphurous acid (by burning sulphur within them) before they are used.

Want of space will not allow of the treatment of wine analysis generally; but sufficient has been said to show how far the genuineness of a wine can be proved by chemical analysis. Against the most important and frequently occurring fraud, namely, the substitution of a genuine, but inferior, for a high class wine of a similar kind, chemical analysis is at present absolutely powerless.

It sometimes happens that wine becomes viscous and forms threads when poured from the bottle. This mischief, which is caused by the development of a foreign ferment, can be cured by the judicious addition of a solution of tannin, which precipitates the “gum.” From a similar cause comes acetous fermentation, which always takes place in a moderate degree, but may assume undue dimensions. Red wines are liable to develop a foreign substance which imparts to them a bitter taste. A wine kept in a mouldy cask assumes of course a mouldy taste and smell. Sometimes a wine will “capsize”: the alcohol and the acid disappear and what was wine becomes an insipid undrinkable liquid. Most of the injurious effects caused in wine by foreign ferments can be prevented by a process introduced by Pasteur. The wine is kept for a sufficient time at a temperature of 70° C. in the absence of air, and then transferred to a germ-free cask, without allowing it to come in contact with more air than can be helped. The only objection to Pasteur’s precautionary method is that it renders the wine slightly flat through the removal of part of its carbonic acid. No doubt these deleterious consequences might be prevented to a very great extent if the fermentation were conducted from the first in casks which communicated with the air only through a (wide enough) tube full of cotton wool, which medium is known to filter off all germs (see Fermentation, vol. ix. p. 95).

Effervescing or Sparkling Wines.— These wines are largely impregnated with carbonic acid engendered by an after-fermentation in the closed bottle by means of added sugar. The art originated in Champagne, where the best sparkling wines are produced, and whence it has spread to the Rhine, the Moselle, and other districts. The natural wine of Champagne is not of a very high order; yet it produces the best champagne. For champagne-making blue grapes are preferred. In eliminating the juice excessive pressure is avoided, so as to keep the must clear of particles of skin. The processes of fermentation and clearing, as well as those connected with the making of champagne generally, are described in detail below (p. 606). Champagne-makers distinguish three grades of effervescence. In mousseux the pressure in the bottle amounts to from 4 to 4£ atmospheres; in grand mousseux it reaches 5 atmospheres; and less than 4 atmospheres’ pressure constitutes cremant (from la crème, “cream ”), a wine which throws up a froth but does not give off carbonic acid violently. A champagne which contains relatively little sugar is called “dry”; it is chiefly this kind which is imported into Great Britain, where champagne is used habitually as a dinner wine. In France a sweet wine is preferred. The intensely sweet substance called “saccharine” (see Sugar, vol. xxii. p. 623) has been utilized for producing a sparkling wine which is both sweet and dry. Cheap champagnes may be (and we believe are) produced by simply adding sugar and some flavouring matter to wine, and then pumping in carbonic acid in the soda-water fashion. The following extract from a table by August Dupré will show the chemical composition of the wines most popular in Great Britain. The numbers may be read as grammes per litre or as ounces per 1000 fluid ounces. [table]

(W. D.)

Part II.— Industry and Trade.

At the present day wine is practically a European product, although a certain quantity is made in the United States, at the Cape of Good Hope, and in Australia. The principal countries in Europe where the vine is grown to any extent are France, Spain, Portugal, Austria-Hungary, Italy, Germany, and the southern portions of Russia and Greece; but in the first six alone is wine an article of much commercial importance.

In the lands of the Levant the use of wine is as old as the earliest memory of civilization, and we find its introduction ascribed to gods (Dionysus in Greece, Osiris in Egypt), or, in the case of the Hebrews, to the patriarch Noah, the second father of mankind. Corn, wine, and oil appear together (as in the Old Testament) as the main gifts of the soil, the material bases of life and comfort. The cultivation of the vine was the highest achievement of ancient husbandry, impossible to semi-nomadic peoples, who might grow a corn crop, but did not remain long enough in one spot to form vineyards. Thus the vine and the olive are in antiquity the marks and almost the symbols of settled and cultured life. Starting perhaps from Armenia and eastern Pontus, viticulture gradually made its way through the lands of ancient civilization, rejected only by a race like the Nabataeans (?.«.), whose laws were directed to prevent the transition from nomadic to settled life (cp. the Old Testament Rechabites). Of Asiatic wines the most famous was that of Chalybon (Helbon) near Damascus, which was an article of Phoenician commerce in the time of Ezekiel (xxvii. 18) and at a later date furnished the tables of the Persian kings. Of Greek wines the most famous came from the islands (as Chios, Lesbos, Cos) or from points on the Asiatic coast (Strabo, xiv. p. 637). The vine reached Spain through the Phoenicians, and Italy and southern Gaul (Marseilles) from Greece; it had no place in the oldest Roman husbandry, nor was wine used in the oldest Roman ritual. But in time Italy became a great wine country, and Cato regards viticulture as the most profitable branch of husbandry. It was indeed artificially fostered by the Roman republic, which prohibited the import of foreign growths into Italy and stimulated exports by restrictions on wine-growing in the provinces, especially in southern Gaul, which thus became a great market for Italian wines. These restrictions were not wholly'removed till the time of Probus (q.v.), when the reins of empire were no longer in Italian hands. In the first century of our era Spanish and Gaulish as well as Greek wines were drunk at Rome (Pliny), but in Gaul the production seems to have been limited to the districts of the Allobroges and Bituriges on the Rhone and the Gironde. It was after Probus’s time that viticulture seems to have been established on the Seine and the Moselle, and Julian when in Gaul still found occasion to discharge an epigram against the false Dionysus of Celtic beer. The northward spread of the vine was doubtless also retarded by difficulties of acclimatization, which were only gradually overcome. In the Middle Ages, when transport was difficult, wine was produced in the south of England and in several parts of Germany where there is now no motive for urging a precarious husbandry. The exact mode of vine-culture and wine-making amongst the ancients is somewhat obscure; but there is reason to believe that the latter, although in a somewhat cruder form, closely resembled the system in use at the present day. As far as viticulture is concerned, we find from Pliny and others that the Romans encouraged the upward growth of the vine upon trees and palisades in preference to the dwarf system now followed in the more northern regions, such as France,—a fact doubtless attributable to the almost tropical luxuriance which the vine attains in Italy. Little comparative information can be obtained as to the style of wine made by the ancients; but from the few facts we do know it may be presumed that, apart from alcoholic qualities, the wines of Greece and Rome had not the high properties possessed by those of the present day.

The introduction of resinous flavours or of salt, then usually resorted to, would hardly suit the present high rearing of vinous products. The vintage in the more favoured districts began towards the end of September and in the less favoured during the following month. Grapes were not gathered until they had attained their fullest maturity, and in many instances they were allowed to dry three or four days in the sun after gathering in order to obtain further sweetness and body. The grapes were trodden and then submitted to the press, much after the custom still prevalent in Burgundy and Portugal. When, however, the juice was deemed too thin and watery for the production of good wine, it was boiled down to a greater consistency, whilst a small portion of gypsum was added to it. The original receptacles for wi□e appear to have been the skins of animals, rendered impervious by oil or resinous substances, but later on the principal vessels were made of earthenware (amphorae and the like) or, in certain districts, though less frequently, of wood, after the style of...