12 BULLETIN" 34&, U. S. DEPARTMENT OF AGRICULTURE. 



weather, the earliest picked grapes drying in 10 days and the later 

 ones often taking four weeks or more. 



The method of drying is very simple. The bunches are cut from 

 the vines and placed in shallow trays 2 feet wide, 3 feet long, and 1 

 inch high (PI. V, figs. 1 and 2), on which the grapes are allowed to 

 sun-dry, being turned from time to time by simply placing an empty 

 tray upside down on the full one and then turning both over and 

 taking off the top tray. After the raisins are dried they are stored 

 away until they are packed and prepared for shipment. Some of 

 the larger growers, in order not to run so much risk in drying on 

 account of rain, and also to enable them to handle the crop fast 

 enough, have curing houses, where the curing is finished after having, 

 been partially done outside. 



DIPPING AND SCALDING RAISINS. 



The operation of dipping and scalding is designed to accomplish 

 several purposes, namely, to cleanse the fruit, to hasten its drying, 

 and to give the dried fruit a lighter color. In dipping and drying, 

 the fruit, immediately after being cut from the vines, is either dipped 

 in clear water to first rinse it of particles of dust and other foreign 

 matter, or it is taken direct to the scalder and immersed in a boiling 

 alkaline mixture called " legia " (lye) until the grapes show an 

 almost imperceptible cracking of the skin, the operation consuming 

 perhaps from one-fourth to one-half of a minute. This dipping 

 calls for skill on the part of the operator, the duration of the im- 

 mersion depending on the strength and temperature of the mixture 

 and the condition of the fruit. Desiccation follows the scalding 

 process, which is accomplished on trays (PL VII, fig. 1) in the sun, 

 the same as undipped raisins cured entirely by solar heat (PI. VII, 

 fig. 2). On account of the scald they cure rapidly, and the fruit is 

 also often of lighter color when cured. The following formula has 

 been used at Woodland, Yolo County, for Sultana and Sultanina 

 grapes : 



Thirty pounds of English bicarbonate of soda are boiled in 30 gallons of 

 water until dissolved, to which are added 70 gallons of water and approximately- 

 one teacupful of genuine olive oil. This mixture is for grapes containing 25 

 per cent of sugar ; should their sugar content be less, more bicarbonate of soda 

 is added. The bicarbonate of soda must be sufficiently strong to remove the 

 bloom of the grape and open the pores of the skin to facilitate drying. The 

 cup of olive oil added forms a thin film on the surface of the solution. This 

 film is preserved while clipping by adding an occasional teaspoonful of oil, the 

 mixture being kept sufficiently warm so that the oil dissolves perfectly and 

 spreads evenly over the surface. Three-fourths of a gallon of olive oil will be 

 sufficient to dip 5 tons of grapes in the mixture as given here. When the solu- 

 tion gets dirty it is renewed. 



