FRUIT PRESSURE TESTERS 



11 



Table 2. — Pressure-test limits of certain apple varieties at picking time and at 

 different degrees of ripeness 



[Plunger, Mb 



of an inch in diameter; penetration, Me. of an inch] 







Variety 



Approximate 



limits of pressure 



test at picking 



time according 



to— 



Limits of pressure test at indicated degree of ripeness 





Magness 

 et al.i 



Mag- 

 ness and 

 Taylor 2 



Hard 3 



Firm 3 



Firm ripe 3 



Ripe 3 



Prime 

 eating 2 



Over- 

 ripe, 

 upper 

 limit 2 



Arkansas (Mammoth 

 Black Twig) 



Pounds 



20± 



25± 



22 to 18 



20 to 4 17 



Pounds 

 24 to 19 



Pounds 

 25 to 18 



Pounds 

 19 to 15 



Pounds 

 16. 5 to 13 



Pounds 

 15 to 11 



Pounds 

 14 to 10 



Pounds 

 10 









22 to 18 

 24 to 18 











12 to 9 



13 to 9 



9 



Ben Davis 



24 to 17. 5 

 30 to 18. 5 

 20 to 16. 5 



18 to 14. 5 

 19. 5 to 15. 5 

 17. 5 to 14 



15 to 12 



16. 5 to 12 

 15 toll 



13. 5 to 8 

 13 to 8 

 12 to 8 



9 



Delicious __ --_ 



18 to < 16 

 18+ 

 18± 



20 to 16 



12 to 8 



8 



Esopus Spitzenburg 























20 to 16 

 27 to 18 



21 to 16 



16. 5 to 13 

 18. 5 to 15 

 16. 5 to 13. 5 



14 to 11 

 16 to 12. 5 

 14 to 10. 5 



11. 5 to 8 

 13. 5 to 9 

 12 to 8 









20 to 18 



16 to 4 15 



18± 



16 to 4 14 



17 to 16 



21 to 17 



20 to 16 



21 to 17 

 19 to 15 



12 to 8 

 12 to 8 

 12 to 8 



11 to 7 



8 



Jonathan _ _ 



8 

 8 













7 



















21. 5 to 16 



17 to 13 



14 to 10. 5 



13 to 7 









22 to 18 



17+ 



20 to 4 18 



18 to * 16 



18± 



21 to 17 



22 to 16 



12 to 8 



13 to 9 



8 



Rome Beauty 



Stark 



23 to 18 



19 to 15 



16 to 12. 5 



13. 5 to 9 



9 



Stayman Winesap 



20 to 16 



21 to 16 



16. 5 to 13 



14 toll 



12 to 7 



12 to 8 



8 



Wealthy 





20 to 16 



26 to 16 



27 to 18 



17 to 13 

 17 to 12 

 19 to 15 



14 to 10 

 13 to 10 



16 to 12. 5 



11 to 6 



12 to 6 

 14 to 9.5 







Williams (Earlv Red) 











Winesap. . ... --- -- 



19+ 

 20± 



20 to 18 



23 to 19 



13 to 9 



9 







Yellow Newtown 

 (Albemarle Pippin),.. 



25 to 20 



21. 5 to 18 

 22 to 16 

 24 to 18 



19 to 15 

 17 to 13 

 19 to 16 



16 to 12 

 14 to 10 



17 to 14 



13 to 10 

 11 to 6 

 15 to 9 



13 to 9 



9 





19± 



24 to 19 



13 to 10 



10 











1 Taken from Magness et al. (45). 



3 Taken from Magness and Taylor (48). 



3 Taken from Haller et al. (29). Degree of ripeness based on definitions in the United States Standards 

 for Apples. 



4 Apples testing lower are likely to be too soft for satisfactory storage. 



It should be emphasized that factors other than pressure test have 

 been used as primary indexes of maturity and that the ranges indicated 

 in table 2 are those at which apples are usually picked but that they 

 may be mature even though averaging higher than the upper limits 

 indicated. 



Magness, Diehl, and Haller (4.6) have used the pressure test as an indi- 

 cation of the ripeness of apples during storage at various temperatures. 

 They found a gradual softening at low temperatures and a rather 

 rapid rate of softening at high temperatures. Magness and Taylor 

 (4-8) indicated the approximate range of pressure test for a number of 

 varieties of apples when in prime eating condition and the upper limits 

 for the overripe and mealy stage. These are given in columns 8 and 

 9 of table 2. Haller et al. (29) attempted to determine the pressure- 

 test range of a number of apple varieties for the degrees of ripeness as 

 defined in the United States Standards for Apples (59). They found 

 that apples of a variety at a given pressure test were generally con- 

 sidered to be of the same ripeness even with different lots that were 

 picked at different maturities or ripened under different temperature 

 conditions. However, it was found that with many lots the pressure 



