EVAPORATING FRUITS. 289 



which has brought so great a boon, not only to the pro- 

 ducer but to the consumer, is that of the evaporation of 

 fruits and vegetables. To be sure, they were evaporated 

 years ago and placed on the market with a great furore, but 

 the principle then employed was totally incorrect, and the 

 result correspondingly disappointing to all concerned. The 

 fruit offered was really cooked and then dried, and not 

 genuinely evaporated at all. The trays were placed one 

 above the other in a box or chamber ; the hot vapor or 

 steam from below was augmented by the moisture from 

 the contents of the lower trays, and the result was that 

 the fruit swelled just as though it had been cooked, the 

 delicate membranous cells burst asunder, and the starch 

 they contained, instead of being converted into grape- 

 sugar or glucose, acidified, and thus both the sweetness 

 and the flavor of the fruit, which is an essential oil held 

 prisoner by these same little cells, dissipated, and conse- 

 quently the whole character of the fruit was changed. 

 The salt had lost its savor, hence, evaporated fruits took 

 no hold on public favor, and those who had invested in 

 expensive driers soon abandoned their use, the universal 

 verdict being that " it did not pay." And yet all felt that 

 there existed a satisfactory solution of the vexed question 

 of perfect evaporation, and within the last few years it 

 has been solved completely by the invention of the "Amer- 

 ican Fruit Drier," by Dr. Ryder. 



He set aside, from the beginning, the erroneous idea 

 upon which the vertical evaporators were constructed, that 

 "evaporated produce should be retained and finished in a 

 humid atmosphere, entering at the point of greatest hu- 

 midity and finishing at the point of greatest heat." Water 

 in dried fruit means decay, acetous fermentation, and con- 

 sequent loss of sweetness and flavor. This theory had 

 failed lamentably in practice, so Dr. Ryder adopted the 



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