716 EXPERIMENT STATION RECORD. fVol. 43 



content of evaporated grapes ; and experiments on stemming, seeding, and 

 paclving evaporated grap6s. 



Dipping the grapes in a dilute boiling lye solution was found appi'oximately 

 to double the rate of drying, the strength of the solution required depending 

 upon the variety of grape. Most wine-grape varieties and Muscat grapes re- 

 quired a 2 or 3 per cent solution, while Tokays and Thompson Seedless required 

 only a 0.5 per cent solution. Sulphuring for a short period was found to 

 shorten the perio.d of drying, to improve the color of the grapes, and to produce 

 a slightly larger yield. No constant difference in yield was obtained in sun- 

 drying and in evaporation. The color and flavor of the juice of sun-dried 

 grapes obtained by soaking in water was inferior to that obtained from evapo- 

 rated grapes. 



Tlie rate of drying was greatly increased by an increase in the temperature 

 of the air used in drying. The temperature of 165° F. is recommended for gen- 

 eral practice. Recirculation of a large proportion of the exhaust air was found 

 to reduce fuel consumption without reducing the rate of drying, and also to 

 prevent the overdrying of the fruit and permit regulation of th(^ moisture con- 

 tent of the dried product. The limit of safety in keeping quality of the mois- 

 ture content of dried grapes was between 25 and 30 per cent. With a moisture 

 content of 20 per cent the finished product was of the most desirable texture. 

 By allowing the dried product to stand in sweat boxes or bins for a number of 

 days equalization in moisture content resulted. 



Dried grapes can be stemmetl satisfactorily when dried to about 10 per cent 

 moisture and stemmed within a few hours after drying. Dried wine grapes 

 were seeded successfully, although with considerable loss. 



In conclusion, attention is called to the indiscriminate use of various terms 

 to designate fruits and vegetables from which most of the water has been 

 removed. A committee appointed to consider the question has made the follow- 

 ing recommendation : 



"(c) The same nomenclature sl^all be applied to fruits and vegetables. 



"(&) The term 'dried' is applied to all fruits and vegetables preserved by 

 the removal of moisture, irrespective of the method of removal. 



"(c) There are but two classes of dried fruits and vegetables, namely, those 

 dried principally by solar heat and those dried principally by artificial heat. 



"(d) The class dried principally by solar heat shall be designated 'sun 

 dried,' by which is meant the removal of moisture by solar heat without con- 

 trol of temperature, humidity, or air flow. 



"(e) The class dried principally by artificial heat shall be designated either 

 ' evaporated ' or ' dehydrated.' The committee finds at this time no suflScient 

 reasons for distinguishing between ' evaporated ' and ' dehydrated '." 



Commercial production of grape sirup, W. V. Cruess {California Sta. Bid. 

 321 (1920), pp. 401-416, figs. 5). — This publication supplements the information 

 on the manufacture of grape sirup given in Bulletin 303, previously noted 

 (E. S. R., 40, p. 414). Of several different types of sirup which have been pro- 

 duced, the three which appear to be mo.st promising are (1) "a sirup of deep 

 violet-red color and rich berry-like flavor, made in vacuum pans of standard 

 design; (2) a sirup, red or white as desired, made by concentrating fresh 

 Muscat or other highly flavored juice by the freezing process and blending this 

 with a sirup of high sugar content made by the vacuum-pan process; (3) a 

 red or white sirup made in a proprietary patented vacuum pan so designed that 

 part of the natural grape flavor is condensed and returned to the sirup." 



The manufacture of the first type of sirup, which is considered to give the 

 best results from a commercial standpoint at present, is described in detail, 



