Artificial bouquets are produced by aromatic substances, or essential oils, whose aroma is extracted or dissolved out by the help of alcohol. The aromatic principle may be extracted either by a simple alcoholic tincture, by digestion or distillation, by dissolving the oils themselves, etc., and the process varies with the substance used.
The aromatic substances most frequently employed to produce artificial bouquets in non-fortified wines, commencing with those which form the base and whose aromas are more dominant, are: iris, strawberry, gillyflower, the flower of the vine, mignonette, nutmeg, bitter almond, fruit pits, sassafras, etc. The latter are rarely employed alone, and play a secondary part by mixing with the two first, iris and strawberry, whose aromas are quite distinctive.
Iris.—There are two varieties of this. The roots only are employed; they are white, of an average diameter of 0 m. 02 (¾ in.), and of a very irregular form. They are sold in pieces about 0 m. 05 (2 in.) long, with the rootlets removed. They are largely employed in perfumery.
The root of the so-called Florence iris, which grows in Italy and the south of France, has a pronounced violet odor. Another variety, which grows in the north of France and in Germany, is sold under the name of German iris. An experienced person can distinguish the two.
The perfume of the iris is with difficulty and incompletely extracted by distillation; it is obtained by infusing the roots in alcohol, after first reducing them to a powder by means of a grater. The operation is long, but indispensable. The powder occurs in commerce, but in that form the roots lose their aroma, and it is moreover liable to be adulterated.
The tincture is prepared in the following proportions: old spirit of wine of 85 per cent., 10 litres (2½ gallons); Florence iris, 1 kilogramme (2⅕ lb.), reduced to powder.
Bung or cork the vessel containing it, stir it about for a few minutes, and then put it in a place of at least 68° F., but which does not go beyond 95°. Shake it occasionally during two weeks, and then press and filter it.
The tincture has a pronounced violet odor, and a harsh, bitter after-taste.
It may be employed alone, in a very small dose, rarely exceeding 5 centilitres per hectolitre (13½ fluidrams to 26½ gallons). Oftener, however, a few drops of the essential oil of gillyflower, etc., are mixed with it.
Strawberry.—The preparation of an alcoholic infusion of strawberries is very simple. Take fully ripe berries, pick them over and hull them, and put them in a keg with a large bung. Ten kilogrammes of fruit to 12 litres of old spirits of wine of 85 per cent. (22 lbs. to 3⅛ gals.) are used. After macerating for twenty-four hours, the liquor is drawn off and filtered. It is a rose-colored liquor of a very pleasant aroma. Then the fruit is crushed, and brandy of 50 per cent. is added, and the whole is allowed to macerate for a month, and then the marc is pressed. The second tincture has an odor and flavor inferior to the first, and has more color. It is filtered, or what is better, distilled in a water bath. In the latter way spirit of strawberry is obtained. It is preferable to employ the liquor of the first infusion. This aroma is generally used alone, and is much employed in the manufacture of sparkling wines. Sometimes a small quantity of other aromatic substances are added, allowing the strawberry to predominate. It is the best modifier of the aroma of young wines.