Home methods of making grape-juice.
The principles involved in making grape-juice in the home are the same as those used in canning. The grapes may be crushed by hand or in mills similar or identical with the small cider-mills owned by many farmers. In making a light-colored juice, the crushed grapes are put in a cloth sack and hung up to drain, or the filled sack may be twisted by two persons until the greater part of the juice is expressed. The juice is then sterilized in a double-boiler by heating it at a temperature of 180° to 200° F., care being taken that the thermometer never goes above 200°. The sterilized juice is now poured into a glass or enameled vessel to stand for twenty-four hours, after which it is drained from the sediment and strained through several thicknesses of clean flannel. The juice is now put in clean bottles preparatory to a second sterilization, care being taken that at least an inch of space is left at the top for the liquid to expand when heated. The second sterilization may be conducted in a wash-boiler or similar receptacle. The filled bottles must not rest on the bottom of the boiler but should be separated from it with a thin board. The boiler is filled with water up to within an inch of the tops of the bottles and heated until the water begins to boil. The bottles should then be taken out and corked immediately, using only new corks. After corking, the bottles are further sealed by dipping the corks in melted paraffin. A cheap corking machine is a great convenience in this work, and in any case the corks should be soaked for at least a half hour in warm but not boiling water.
The process varies somewhat in the making of red grape-juice. The crushed grapes are heated to a temperature of 200° F., and are then strained through a drip bag without pressure, after which the liquid is set away in glass or enamel vessels to settle for twenty-four hours. Except for this difference in the preliminary treatment of the juice, the methods are the same in making the red or the light-colored product. For proper keeping it is not necessary to let the juice settle after it is strained, but a clearer and brighter product is obtained if the juice is permitted to settle. In either case the grape-juice should keep indefinitely if the work has been well done. As soon as bottles are opened, fermentation begins with the formation of alcohol.
Raisins
The grape is best conserved as a raisin. Canning is seldom practiced with this fruit. A raisin is a dried grape. Tree-fruits are evaporated as by-products, but the raisin is a primary product. This is a difference worth noting; for with tree-fruits the cream of the crop goes to the fresh fruit market, while with the grape the entire crop of raisin varieties may go into the cured product. The raisin industry is dependent on a sunny and rainless climate and hence in America is confined to the grape regions of certain parts of California. In this state, raisin-making is a rich resource of the grape-grower, the annual output now averaging well above 200,000 pounds, grown on 120,000 acres of land, and having a market value of $10,000,000. Fresno County, California, produces nearly 60 per cent of the output of the state and the city of Fresno is the center of the industry. The raisin industry does not stand alone in California, as some raisin grapes, notably Muscat of Alexandria, are good dessert sorts and are also much used for wine and brandy. Only the first crop of the variety named is used for raisins, while practically all of the second crop each season is made into wine and brandy.
Raisins proper are mostly made from the Muscat of Alexandria, although other large, white, sweet grapes are sometimes used. Sultana raisins, naturally seedless, are made from Sultanina and the Sultana. The dried currants of commerce are made from grapes, and of these California produces small quantities from White Corinth.
The following account of raisin-making is given by Husmann:[20]
"In the raisin districts grapes are ripe by the middle of August, the season often lasting into November. The average time necessary for drying and curing a tray of raisins is about three weeks, depending on the weather, the earliest picked grapes drying in ten days and the later ones often taking four weeks or more.
"The method of drying is very simple. The bunches are cut from the vines and placed in shallow trays 2 feet wide, 3 feet long, and 1 inch high on which the grapes are allowed to sun-dry, being turned from time to time by simply placing an empty tray upside down on the full one and then turning both over and taking off the top tray. After the raisins are dried they are stored away until they are packed and prepared for shipment. Some of the larger growers, in order not to run so much risk in drying on account of rain, and also to enable them to handle the crop fast enough, have curing houses, where the curing is finished after having been partially done outside."