EVAPORATION OF FRUITS. 43 



loaded to a depth of 5 to 6 inches in about 12 hours, 10 to 18 hours 

 being the range of variation. Where the fruit is handled on trays, 

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

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

 on the trays. For slices 5 hours is considered a reasonable time, 

 with a range of 4 to 8 hours. 



It is estimated that quarters will require from 18 to 24 hours in the 

 average kiln, while the time for whole apples will range from 36 to 

 48 hours. 



If the atmospheric conditions are heavy and damp, the drying is 

 retarded. Under some conditions it is hardly possible to dry the fruit 

 thoroughly. During windy weather, also, it is more difficult to regu- 

 late the heat, especially if the walls are poorly constructed and if hop- 

 pers about the furnaces are not employed, so that the draft of cold 

 air into the furnace room can not be controlled. This applies espe- 

 cially 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 to determine when 

 the fruit is sufficiently dried to meet the requirements. 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 sep- 

 arate at once upon being released from the hand. In this condition 

 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. In general, the fruit as it is handled should feel 

 soft and velvety and have a pliable texture. This is a critical stage, 

 since the slices may seem to possess these characteristics in the proper 

 degree while warm, but after they are removed from the evaporator 

 and have become cold they may be so dry as to rattle unless the 

 removal has been very accurately timed. 



The foregoing should represent as nearly as possible the average 

 condition, but it can not be expected to be absolutely uniform 

 throughout. Some slices — they should constitute only a very small 

 percentage — will still plainly possess some of the juice of the apple; 

 others — likewise, properly only a small proportion — will be entirely 

 too dry, possibly dry enough to be brittle. 



The curing or conditioning room, — When a quantity of fruit is 

 considered dry enough it is removed from the kiln and put in a pile 

 on the floor of the curing room. (Fig. 14.) Every day or two the 

 pile should be thoroughly shoveled over to make uniform the changes 

 which take place. Thus managed, the pile in a few days will become 

 thoroughly homogeneous. The pieces that were too dry will have 

 absorbed moisture, the superfluous moisture of other pieces will have 

 disappeared, and the entire mass may be expected to reach the condi- 

 tion above described. When this condition has been reached, the 

 batch may be added to the general stock in the storage room. 



The conditioning room may be, and in most plants actually is, a 

 portion of the second-floor workroom. It should be partitioned off 

 from the remainder of the room, the windows and door should be 



