EVAPORATION OF FRUITS. 51 



While the details of handling the fruit at the evaporator vary 

 considerably with different operators, a composite course is about 

 as here described. 



SIZING THE FRUIT. 



The fruit is emptied from lug boxes or other receptacles upon the 

 grader, set to separate the fruit into four or five sizes, which are 

 kept apart 'through the subsequent treatment. Sizing well repays 

 the labor, since more uniform checking in the dip and greater uni- 

 formity in drying, with a corresponding decrease in the percentage 

 of " bloaters " and " frogs " 7 is thereby secured. 



DIPPING THE FRUIT. 



The fruit is dipped in a lye solution, the object of which is to 

 remove the wax from the fruit and to produce a very fine checking of 

 the skin. If this is not done, the moisture in the fruit can not 

 escape readily, and the fruit in drying will not assume the shrunken 

 condition that is desirable. Instead, many " frogs " or " chocolates," 

 as they are variously called, i. e., fruits which do not assume the 

 desired shrunken condition, will result. Such fruits have to be 

 graded out and are worthless, or nearly so, as dried prunes. 



The lye solution is made by dissolving ordinary high-grade caustic 

 soda or caustic potash in water. The strength at which it is used 

 varies from a pound in 10 or 12 gallons of water to a pound in 25 or 

 30 gallons of water, depending upon the variety (some requiring a 

 stronger solution than others to accomplish the end in view), the 

 ripeness of the fruit (fully ripe, fallen fruit requiring shorter treat- 

 ment than that which has been shaken or beaten from the trees), 

 the temperature at which the solution is maintained, the length of 

 time the fruit is immersed, etc. 



Ordinarily the lye solution is maintained at the boiling point, the 

 tank in which it is contained being placed over a furnace or supplied 

 with steam coils in such manner as to maintain the desired tem- 

 perature, as described in the section on equipment, page 33. 



When the solution is maintained at this high temperature, it is 

 necessary to hold fully ripe fruit in the solution only a few seconds, 

 though the time varies to some extent with different varieties. The 

 operator soon learns to determine by the appearance of the fruit the 

 necessary length of time under the temperature and other conditions 

 that are being maintained. If the solution is too strong, or if the 

 fruit is immersed for too great a length of time, the slight checks in 

 the skin will become definite cracks in the fruit. This should be 

 avoided, as fruits which are definitely cracked will lose much of their 

 sugar by dripping and consequently will not make a desirable dried 

 product. 



Immediately after dipping, the fruit should be transferred to a 

 bath of clear water and rinsed free from lye. The wash water should 



7 The terms " bloaters," " frogs," and " chocolates " are variously used to denote fruits 

 that do not dry properly, but remain plump and retain certain other undesirable charac- 

 teristics. "Bloaters" (California Exp. Sta. Bui. 114) have been designated as large, 

 fully ripe fruits which ferment slightly in drying, producing a small amount of gas which 

 prevents them from shrinking. " Frogs " are usually small, poorly developed fruits which 

 for some reason will not respond properly to the lye solution. The skin does not become 

 checked, and they do not dry properly. If a tree is very heavily overloaded and the fruit 

 correspondingly small and poorly developed, much of the fruit from it is likely to " frog " 

 when dried. 



