TEMPERATURE CHANGES IN CANNING FRUITS AND VEGETABLES. 19 



approaches that of the retort or bath. It requires about 30 minutes 

 for the pint glass jar and about 35 minutes for the quart jar to reach 



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Fig. 12. — Time-temperature relations for string beans in 2 per cent brine 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 temperature during cooling in water were plotted from, readings made at in- 

 tervals of | minute and 1 minute ; those representing fall in temperature during 

 cooling in air, from readings at intervals of 5 to 10 minutes. Rise in temperature 

 whpn processed : A, At 100° C. ; B, at 109° C. ; C, at 116° C. ; D, at 121° C. Fall in 

 temperature when cooled: a', From 100° in water at 17° C. ; V, from 109° in water 

 at 161° C. ; C, from 116° in water at 16i° C. ; d' , from 121° in water at 16J° C. ; 

 a, from 100° in air at 251° C. ; b, from 109° in air at 25i° C. ; c, from 116° in air at 

 251° C. ; d, from 121° in air at 22° to 26° C. 



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Fig. 13. — Time-temperature relations for string beans in 2 per cent brine 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 *rom read- 

 ings made at intervals of 1 minute ; the curve representing the cooling in air, from 

 readings at intervals of 1 to 5 minutes. Rise in temperature when processed : 

 A, At 100° C. ; B, at 109° C. ; C, at 116° C. ; D, at 121° C. a, Fall in temperature 

 from 100° when cooled in air at 18° to 22° C. 



the same temperature. It is evident that so far as time-temperature 

 relations in the can are concerned there need be little difference in 



