TEMPERATURE CHANGES IN CANNING FRUITS AND VEGETABLES. 13 



fell to 100° C. us rapidly as the temperature of the retort was low- 

 ered. The temperature at the center of the glass container was thus 



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Pig. 5. — Time-temperature relations for distilled water when processed in No. 3 tin cans 

 at 100°, 109°, 116°, and 121° C. and also when cooled in water and in air. The 

 curves representing the rise in temperature during- processing and the fall in tempera- 

 ture during cooling in water were plotted from readings made at intervals of 30 sec- 

 onds ; curves representing cooling in air, from readings at intervals of 5 to 10 minutes. 

 Rise in temperature when processed : A, At 100° C. ; B, at 109° C. ; G, at 116° C. ; 

 D, at 121° C. Fall when cooled : a', From 100° C. in water at 16° C. ; V, from 109° C. 

 in water at 17° C. ; c', from 116° C. in water at 15° C. ; d', from 121° C. in water at 

 17° C. ; a, from 100° C. in air at 16° C. ; b, from 109° C. in air at 25° C. ; c, from 116° 

 C. in air at 25° C. ; d, from 121° C in air at 25° C. 



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 TIME /N M/HUTES 



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Fig. 6. — Time-temperature relations for distilled water when processed in pint glass jars 

 at 100°, 109°, 116°, and 121° C. and also when cooled in air. The curves representing 

 the rise in temperature during processing were plotted from readings made at intervals 

 of 30 seconds ; the curve representing cooling in air, from readings at internals of 

 5 to 15 minutes. Rise in temperature when processed : A, At 100° C. ; B, at 109° C. ; 

 C, at 116° C. ; D, at 121° C. a, Fall from 100° C. when cooled in air at 15° to 20° C. 



always at 100° C. when taken from the retort, and the cooling curve 

 from this starting point is all that is given. In the case of the tin 



