This system is open to the objection that the fruit must be shoveled over from time to time to insure uniform drying. If not skillfully done, some will be too dry while other parts will not be dry enough. The handling itself is likely to damage some fruits. However, a skilled man these objections. The system has some very decided advantages over the tower system. Kilns are cheaper to build, are less likely to take fire, and require much less labor to operate. In some neighborhoods the tower evaporators are now being replaced by the kiln system for evaporating apples.
Tower or flue eraporators.—The tower evaporators are the commonest ones in New York, where apple evaporating has become such a great industry. They consist of a chimney-like structure of wood or brick extending from the basement of the building to a point higher than the roof. A stove or furnace in the basement furnishes hot air that passes through the tower.
The tower is usually three to four feet square and is provided with an endless chain or other lift ing device on which the screens may be placed. The screens of fresh apples are placed in the tower at the first floor. By means of the lifting device, the entire charge can be lifted by one operation, so that the screens gradually rise as more are added at the bottom. The screens of evaporated fruit are removed on the second floor. In some forms there is a double shaft, so arranged that the screens are carried up to the top and down again in the other side of the shaft, so that they may be removed on the first floor. It will be seen that in the former case the fresh fruit is placed directly in the hottest part of the shaft, so that the vapor and steam from this pass through the fruit that is partly dried, while in the cabinet evaporators it is placed in the coolest part and comes to the hottest part as the drying nears completion. There is some dispute as to which of these methods is the more desirable, but the latter seems to be so.
In Fig. 262 is shown an evaporator with three brick towers. Each of these towers has a capacity of twenty-five trays, each forty-nine inches square. Such a plant will evaporate about fifty bushels of apples or 1,600 quarts of raspberries per day for each tower.
Handling the crop.
If the entire crop of an orchard is to be evapo rated, the apples are shaken from the trees. They are cored, pared and sliced by machinery. Be fore slicing,they are inspected by a"trimmer," who removes an y remaining skin, core or de cayed places.
Before evapora ting, the apples are paced in the fumes of burn ing sulfur for a few minutes for the purpose of bleaching.
With a one tower evapora tor, fifty to sixty bushels can be evaporated in one day by one parer, two trimmers, one slicer, and one man to tend the evaporator,—five persons, four of whom may be women and children. If kilns and self-feeding slicers are used, the labor may be much reduced. The average cost per bushel of evapora ting is eleven to fifteen cents. A bushel (50 pounds) of apples produces five to eight pounds of dried stock. The early apples produce less than the winter varieties. There is also much difference between different varieties of the same season. If properly dried, the average is six and one-fourth to seven pounds. Apples that are not suitable for drying are chopped and evaporated without paring or coring, and are sold as "chops." The cores and skins are also dried, and are sold for the manufacture of jellies and wines.
Raspberry evaporating.
One of the other important evaporated fruits is the raspberry. Usually only the black varieties are dried. There is not much demand for red ones, and they are so tender as to require more careful handling and give less dried stock per quart. For evaporating, the berries are sometimes hand-picked and are sometimes "batted." In the latter method of harvesting, the picker carries a frame covered with cloth and so arranged that the berries that strike against it are caught at the bottom. The vines are pulled in with a hook and are hit with a bat, so that the berries fall into the box at the bottom. The process of evaporation is much like that for apples, except that no sulfur is needed, and that, if a kiln is used, the floor is usually covered with muslin cloth. It requires about three to four quarts (four to five pounds) of berries to give one pound of dried berries.
Literature.
Bulletin No. 100, Cornell Experiment Station, and Farmers' Bulletin No. 213, Department of Agriculture, discuss different types of evaporators in detail and describe the methods of raising and evaporating raspberries (Fig. 256 is adapted from the latter); Bulletins Nos. 226, 229 of the Cornell Station give statistics and some discussion of apple evaporating in New York; Yearbook, United States Department of Agriculture, 1898, p. 309; Farmers' Bulletin No. 291, Evaporation of Apples, H. P. Gould, from which Fig. 259 is taken.