Aug. 1, 1924 
Freezing Injury of Apples 
115 
dents of packing, as mentioned above. 
After the first 16 hours the fruit in the 
top of the barrel is warmer than that 
elsewhere. Freezing began in the fruit 
at the bottom of the barrel after about 
24 hours; in 12 more hours, or 36 hours 
from the beginning of the experiment, 
apples in the other positions also began 
to freeze. 
For purposes of comparison the tem¬ 
perature curve for the bottoms of the 
two barrels of Winesap apples frozen at 
20° F. and at 25° are presented together 
in Figure 10. Although the two initial 
temperatures are not the same, making 
exact comparison impossible, there is 
some indication of a more rapid rate 
of temperature fall in the bottom of the 
two boxes indicates that wrapping tends 
to equalize these differences, at least at 
the exterior temperatures prevailing 
during the experiment, and to make 
the temperature more uniform through¬ 
out the box. In the box of unwrapped 
apples freezing took place in amounts 
sufficient to influence the temperature 
curve not long after 12 hours. While 
there is some indication of freezing 
between 24 and 36 hours in the wrapped 
apples, the temperature curves do not 
assume a more permanent horizontal 
direction until 42 hours. 
The relative lengths of time for 
which the temperature curves for the 
bottom of the boxes remain horizontal, 
or at the freezing point, should be noted. 
Fig. 10— Comparison of the temperatures obtaining in the bottom of a barrel 
of unwrapped Winesap apples, during exposure to external temperatures around 
25° F. for 96 hours with those obtaining in a barrel xluring exposure to tempera¬ 
tures at or below 20° F. for the same length of time 
• 
barrel exposed to 20° or below, while 
undercooling is definitely indicated in 
this case. The apples at the lower 
temperature began to freeze about 18 
hours earlier. 
The graphs showing the temperatures 
for the wrapped and unwrapped apples 
exposed to 20° F. or below are given 
in Figure 11, several facts being brought 
out in the curves. The much more 
rapid drop in temperature in the box 
of unwrapped apples is clearly defined, 
and both the top and bottom readings 
indicate that undercooling occurred, 
being particularly marked in the bot¬ 
tom. Consideration of the compara¬ 
tive differences existing between the 
readings for the top and bottom of the 
At the close of the experiment the bot¬ 
tom temperature for the unwrapped 
apples was 3° lower than for the 
wrapped ones. That this has a prac¬ 
tical bearing on the possible injury to 
the fruit will appear obvious in the 
light of other experiments in the tem¬ 
peratures at which freezing injury 
occurs and emphasizes the value of 
wrapping boxed fruit as a means of 
partial protection from low tempera¬ 
tures and resultant freezing. 
Figure 12 compares the curves for 
the apple temperatures in the bottom 
of the barrel and in the lower part of 
the boxes. The comparative rates of 
the temperature drop in the barrel and 
box of wrapped apples clearly show 
