184 HORTICULTURE, FORESTRY, FLORICULTURE 



of evaporator ; depth to which fruit is spread ; method of preparing 

 whether sliced, quartered, or whole; temperature maintained; con- 

 ditions of the weather, and, to a certain extent, the construction of 

 the evaporator. 



The application of these several factors to the point in question 

 readily follows. A good kiln evaporator should dry a floor of slices, 

 other things being equal, in about twelve hours, ten to fourteen hours 

 being the range of variation. Where the fruit is handled on racks 

 the time required is much shorter, but conditions are quite different 

 from the kilns, as the fruit is seldom more than 1 or 2 inches thick 

 on the racks. For slices, five hours is considered a reasonable time, 

 with a range of four to six hours. It is estimated that the quarters 

 will require from eighteen to twenty-four hours in the average kiln, 

 while the time for whole apples will range from thirty-six to forty- 

 eight hours. 



If the atmospheric conditions are heavy and damp, the drying 

 is retarded. Under some conditions it is hardly possible to thor- 

 oughly dry the fruit. During windy weather also it is more difficult 

 to regulate the heat, especially if the w^alls are poorly constructed so 

 that the draft of cold air into the furnace room can not be controlled. 

 This applies especially to kilns heated by furnaces. It is claimed 

 that steam-heated evaporators are less subject to the influence of 

 climatic conditions. 



When Is the Fruit Dry? Perhaps there is no step in the entire 

 process that requires better-trained judgment than the matter of de- 

 termining when the fruit is sufficiently dried to meet the require- 

 ments. Like several other steps in the process it is largely a matter 

 of experience, though there are certain general features which are 

 capable of being reduced to words. 



The fruit should be so dry that when a handful of slices is 

 pressed together firmly into a ball the slices will be "springy" enough 

 to separate at once upon being released from the hand. In this con- 

 dition there will be no fruit, or only an occasional piece, that has 

 any visible moisture on the surface. In a slice of average dryness, 

 it should not be possible to press any free juice into view in a freshly 

 made cross section of it. The general "feel" of the fruit, as it is han- 

 dled, should be a soft, velvety, leathery texture. 



Temperature Maintained. The temperature maintained in 

 kilns or other drying compartments, in actual practice is largely a 

 matter of experience, not a factor governed by any definite stand- 

 ards or regulated in accordance with thermometer readings, as might 

 be expected. In general, the object in view is to force the heat as 

 high as possible without endangering the fruit. A probable temper- 

 ature which has been suggested by some of the operators is 150 F., 

 or more when the fruit is first put into the drying compartment, 

 dropping to about 125 F. as the drying process nears completion. 

 Sufficient and proper provision for controlling the indraft of cold air 

 below the fruit will aid in maintaining the desired temperature. 



Weight of Evaporated Apples. Some varieties of apples will 

 make more evaporated stock to the bushel than others. The grade 



