EVAPORATION OF FRUITS. 55 



is passed and as soon as it can be done without mashing the indi- 

 vidual fruits, the contents of each tray should be turned over occa- 

 sionally to insure as far as possible uniformity in drying-. Turning 

 may be done with a small wooden-toothed rake or wooden scoop. In 

 the tunnel evaporator, turning is postponed until the fruit has 

 reached the- lower end of the tunnel. 



The length of time required to hold the fruit in the evaporator 

 depends upon the same general factors that determine the time for 

 other fruits — the weather conditions, type and management of the 

 evaporator, and the variety of the berry. Some varieties dry quicker 

 than others under the same conditions. Then, too, first pickings of 

 the fruit frequently contain more moisture ; hence, they require a 

 longer time in which to dry than the later ones, particularly if the 

 end of the berry season is accompanied by a drought, as is frequently 

 the case. Employing the temperatures here recommended, it is pos- 

 sible to dry berries in the tunnel evaporator in six to eight hours, the 

 trays being spread with 1 quart of berries to the square foot. On the 

 kiln, a laj^er of berries 4 to 5 inches in depth will require 10 to 12 

 hours. 



Under some conditions, the rate of drying and consequently the 

 length of time the fruit remains in the evaporator, is made a matter 

 of convenience to some extent. For example, the conditions in one 

 region where large quantities of black raspberries are dried are such 

 that it is convenient to place the fruit which is harvested during the 

 day on the kiln floor late in the afternoon. The furnace is at once 

 started, running the heat at once as high as the operator thinks the 

 fruit will stand. The fruit is turned early the next morning and 

 again in the middle of the forenoon, and by 3 or 4 o'clock in the 

 afternoon it is ready to go to the curing room, the heat having been 

 allowed to subside somewhat during the latter portion of the time. 

 Upon the removal of the fruit, the kiln is again ready for another 

 " run " with the fruit harvested during the day. While it might be 

 possible to dry the fruit in a shorter period of time, this program is 

 a convenient one under some conditions. 



It is estimated that a ton of hard coal will dry about a ton of 

 berries, but the quantity varies from half a ton to 2 tons of coal to 

 a ton of fruit, depending on the variety, condition of the fruit, and 

 other factors. 



Experience alone will enable the operator to tell with certainty 

 when the fruit is dry enough to be removed from the evaporator. 

 When this stage is reached, some of the fruit will be dry enough to 

 rattle; there will also be fruits (the proportion should be very small) 

 obviously containing too much moisture. The bulk of the fruit 

 should be of such a texture that it will stick to the hand somewhat 

 if squeezed tightly, while yet the individual fruits can not be forced 

 into a mushy condition ; or another test may be to carry the drying 

 as far as possible without reaching the point where the fruit will 

 rattle as it is handled over on the trays. The fruit is then removed 

 from the trays and conditioned in the same manner as apples and 

 other fruits by being placed in bulk on a smooth, clean, tight floor 

 where it is handled over each day with a scoop or other suitable im- 

 plement for a period of perhaps two or three weeks. During this time 

 the fruit is becoming uniform throughout with regard to moisture, 



