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.