As the swell in freezing improves the texture, it is desirable to obtain
it in home-made ice cream. In the home-made ice cream the freezer is
often filled so full that there is no room for overrun and no air is beaten
into the ice cream during freezing. Filling the freezer two-thirds to three-
fourths full gives good results for home-made ice cream. In home freezing
the overrun obtained is seldom as great as with commercial ice creams,
for the freezing conditions in the home are not controlled so carefully as
in the factory.
Too great an overrun produces an ice cream of poor body and quality,
for it becomes very frothy and foamy. An overrun of 50 per cent is con-
sidered to give a desirable texture.
Percentage overrun. The percentage of overrun depends upon the
speed of freezing and rate of turning.
TABLE 12
Effect of the Speed of the Machine on Overrun (Baer)
Revolutions per
minute
Overrun
Time of freezing
Lot I
Lot II
Lot I
Lot II
50
50
50
150
150
150
175
175
175
25
28
25
48
48
50
45
50
52
33
33
35
43
39
40
58
50
55
10
11
9
7
8
7.5
7
7.5
8
11
10
12
7
5
6
6
6.5
6
The above table, from Baer's results, shows the effects of the speed of
the machine on the overrun. He concluded that 50 revolutions per minute
were too slow, as the overrun was too low, the texture of the ice cream
was coarse, and the body weak and spiny.
From the table it will also be noted that increasing the speed of the
freezer shortens the freezing time. The first crystals are formed at the
edge of the ice-cream mix and against the side of the metal container.
The faster speed of turning keeps these crystals scraped away and brings
warmer portions of the mix against the can to be frozen. In this way the
94 FREEZING
whole mass is chilled and frozen more rapidly than it would be if the
mix were not stirred.
For home freezing it is probably better to over-freeze a little but not
too much, if the ice cream is to be served soon after it is frozen. After
stirring is stopped the rate of cooling is slower. Therefore it requires a
period of standing after the freezing process is completed for the ice
cream to harden suitably for serving. Increasing the quantity of salt for
packing also increases the rate at which the ice cream hardens.
The Factors Affecting the Viscosity of Cream
and Ice Cream
Aging. Sherwood and Smallfield have reported that in some cases
aging shows an increase in viscosity of the cream whereas in others it does
not. When the viscosity is increased the fat globules are larger and clump.
They have found that agitation of the cream reduces the size of the fat
globules and the viscosity of the cream. Mortensen states that cream
just separated from fresh milk should be aged 24 hours before it is used
in ice cream, even if it is not pasteurized. Aging also gives a cream that
whips better. The viscosity of a cream increases noticeably for about 6
hours after it is separated and then increases at a slower rate.
Homogenization. Williams lists the benefits of homogenization, as
applied to ice cream, under 6 heads as follows:
1. Increased viscosity.
2. Reduction in time required for aging.
3. Less physical and mechanical loss of fat.
4. Better whipping qualities.
5. Better freezing qualities.
6. Greater uniformity and palatability.
Page 75
Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
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As the swell in freezing improves the texture, it is desirable to obtain
it in home-made ice cream. In the home-made ice cream the freezer is
often filled so full that there is no room for overrun and no air is beaten
into the ice cream during freezing. Filling the freezer two-thirds to three-
fourths full gives good results for home-made ice cream. In home freezing
the overrun obtained is seldom as great as with commercial ice creams,
for the freezing conditions in the home are not controlled so carefully as
in the factory.
Too great an overrun produces an ice cream of poor body and quality,
for it becomes very frothy and foamy. An overrun of 50 per cent is con-
sidered to give a desirable texture.
Percentage overrun. The percentage of overrun depends upon the
speed of freezing and rate of turning.
TABLE 12
Effect of the Speed of the Machine on Overrun (Baer)
Revolutions per
minute
Overrun
Time of freezing
Lot I
Lot II
Lot I
Lot II
50
50
50
150
150
150
175
175
175
25
28
25
48
48
50
45
50
52
33
33
35
43
39
40
58
50
55
10
11
9
7
8
7.5
7
7.5
8
11
10
12
7
5
6
6
6.5
6
The above table, from Baer's results, shows the effects of the speed of
the machine on the overrun. He concluded that 50 revolutions per minute
were too slow, as the overrun was too low, the texture of the ice cream
was coarse, and the body weak and spiny.
From the table it will also be noted that increasing the speed of the
freezer shortens the freezing time. The first crystals are formed at the
edge of the ice-cream mix and against the side of the metal container.
The faster speed of turning keeps these crystals scraped away and brings
warmer portions of the mix against the can to be frozen. In this way the
94 FREEZING
whole mass is chilled and frozen more rapidly than it would be if the
mix were not stirred.
For home freezing it is probably better to over-freeze a little but not
too much, if the ice cream is to be served soon after it is frozen. After
stirring is stopped the rate of cooling is slower. Therefore it requires a
period of standing after the freezing process is completed for the ice
cream to harden suitably for serving. Increasing the quantity of salt for
packing also increases the rate at which the ice cream hardens.
The Factors Affecting the Viscosity of Cream
and Ice Cream
Aging. Sherwood and Smallfield have reported that in some cases
aging shows an increase in viscosity of the cream whereas in others it does
not. When the viscosity is increased the fat globules are larger and clump.
They have found that agitation of the cream reduces the size of the fat
globules and the viscosity of the cream. Mortensen states that cream
just separated from fresh milk should be aged 24 hours before it is used
in ice cream, even if it is not pasteurized. Aging also gives a cream that
whips better. The viscosity of a cream increases noticeably for about 6
hours after it is separated and then increases at a slower rate.
Homogenization. Williams lists the benefits of homogenization, as
applied to ice cream, under 6 heads as follows:
1. Increased viscosity.
2. Reduction in time required for aging.
3. Less physical and mechanical loss of fat.
4. Better whipping qualities.
5. Better freezing qualities.
6. Greater uniformity and palatability.