RIPENING, STORAGE, AND HANDLING OF APPLES 



13 



west and the southern portions of the eastern apple-growing re- 

 gions. Such varieties are sometimes left on the trees until late, 

 to obtain size and color. By measuring the firmness of the 

 apples the pressure test indicates when the fruit on the tree is 

 becoming so soft that loss is likely to occur. As will be mentioned 

 later, other tests for time of picking are not always satisfactory in 

 determining whether or not the fruit is becoming too ripe to hold up 

 satisfactorily in storage. The average rate of softening in apples 

 appears to be about a pound a week during the last month of the 

 growing season. So long as Jonathan apples are testing 15 pounds 

 or above, Delicious 16 pounds or above, and Grimes Golden 18 

 pounds or above, there is little probability that they are becom- 

 ing too mature for good storage holding. Thus, it appears 

 that, in addition to the tests now in use to determine optimum 

 picking dates, the mechanical-pressure test will prove valuable for 

 these varieties. For firmer varieties, such as Winesap, York Im- 



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Fig. 7. — Change in firmness of flesh and size of Ben Davis apples, 1924 



perial, and Yellow Newtown, which usually begin to drop before 

 becoming so soft as to endanger their storage quality, its use is less 

 essential. 



GROUND COLOR OF APPLES 



The change in the color of the unblushed portion of apples from 

 green to yellow or }^ellow-green has been extensively recommended 

 as a satisfactory test to determine when the fruit is ready to remove 

 from the tree. Corbett (6) has made this color change a basis for 

 picking recommendations. Ramsey et al. (17) state "perhaps the 

 most reliable single indication [of maturity] is the ' ground ' color 

 of the fruit ; that is, the color which underlies the red color or blush. 

 The ' ground ' color, which is green when the fruit is immature, 

 begins to whiten or yellow slightly as it approaches full maturity. 

 ... As a rule, in a mature apple the green color should be largely 

 replaced by a white or light-yellow color." 



