Effect of Moist Heat. Other candies are
prepared by dissolving sugar in a liquid and
heating the sirup to facilitate the solution.
The crystalline form of the sugar is lost and
it combines readily with other sirups. As the
heating continues above boiling, the water
evaporates and the solution becomes more
concentrated.
A basic problem in making candies with
added liquid is to know when the sirup has
[35]
Taylor instrument Company
Candy Thermometer • The boiling point of the
sirup is a measure of the concentration. This
sirup has not reached soft ball
reached the concentration desired or when
the candy is "done.” This is the point at
which most amateur candymakers fail.
As the water boils off, the sirup becomes
more concentrated and the boiling point
rises. Water boils at 212° F., but if sucrose
is dissolved in that water, the boiling point
is raised. The rise in the boiling point is in
direct proportion to the amount of sucrose
dissolved in the water. Therefore the boil¬
ing temperature is a definite and satisfactory
method of measuring the concentration of sir¬
ups. Any chemical thermometer can be used
to measure the temperature at which a liq¬
uid boils. Special candy thermometers also
are available.
In determining the boiling point the
bulb of the thermometer should be com¬
pletely immersed in the boiling sirup, not
just inserted in the bubbles on top. It
should not touch the pan at any point. To
read the temperature accurately, the eye
should be on a level with the point on the
scale where the mercurv stands.
The consistency of the sirup when poured
into cold water, such as soft ball, hard ball,
and crack, can be used to test concentration.
This method is wasteful of material, and
results are influenced by the temperature
of the water. It is useful, however, in estab¬
lishing the boiling points at which standard
concentrations are reached. The boiling
points of sucrose sirup corresponding to the
common household test for consistency are
given in Table X.
Different sugars affect the boiling point
differently. When recipes use large amounts
of sugar other than sucrose, the boiling point
for that particular solution should be verified
by use of the consistency test. This boiling
point can be used in the future for that same
recipe.
The influence of any substance on the
boiling point is in proportion to the number
of molecules present in a given volume of the
solution. The dextrose molecule, like the
other simple sugars, is half the size of the
cane-sugar molecule. Dextrose or any of
the simple sugars therefore will have twice
the influence in raising the boiling point as
the same weight of cane sugar. The rise
in the boiling point at the soft-ball stage
then would theoretically be twice as great
with dextrose alone as with sucrose alone.
On the other hand, corn sirup contains
some dextrin, which has a higher molecular
weight than sucrose. Sirups made from a
glucose sirup high in dextrins may contain
fewer molecules per unit of weight than
sirups made from sucrose. This would lower
the boiling point.
This fact is recognized by professional
candymakers. They warn against the danger
of cooking candies containing commercial
glucose to too high a temperature. The point
at which such sirup darkens is about 20° F.
below that of a sirup made from granulated
sugar.
Page 32
Presented as published in 1935. 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
Effect of Moist Heat. Other candies are prepared by dissolving sugar in a liquid and heating the sirup to facilitate the solution. The crystalline form of the sugar is lost and it combines readily with other sirups. As the heating continues above boiling, the water evaporates and the solution becomes more concentrated.
A basic problem in making candies with added liquid is to know when the sirup has
[35]
Taylor instrument Company
Candy Thermometer • The boiling point of the sirup is a measure of the concentration. This sirup has not reached soft ball
reached the concentration desired or when the candy is "done.” This is the point at which most amateur candymakers fail.
As the water boils off, the sirup becomes more concentrated and the boiling point rises. Water boils at 212° F., but if sucrose is dissolved in that water, the boiling point is raised. The rise in the boiling point is in direct proportion to the amount of sucrose dissolved in the water. Therefore the boiling temperature is a definite and satisfactory method of measuring the concentration of sirups. Any chemical thermometer can be used to measure the temperature at which a liq¬ uid boils. Special candy thermometers also are available.
In determining the boiling point the bulb of the thermometer should be com¬ pletely immersed in the boiling sirup, not just inserted in the bubbles on top. It should not touch the pan at any point. To read the temperature accurately, the eye should be on a level with the point on the scale where the mercury stands.
The consistency of the sirup when poured into cold water, such as soft ball, hard ball,
and crack, can be used to test concentration. This method is wasteful of material, and results are influenced by the temperature of the water. It is useful, however, in estab¬ lishing the boiling points at which standard concentrations are reached. The boiling points of sucrose sirup corresponding to the common household test for consistency are given in Table X.
Different sugars affect the boiling point differently. When recipes use large amounts of sugar other than sucrose, the boiling point for that particular solution should be verified by use of the consistency test. This boiling point can be used in the future for that same recipe.
The influence of any substance on the boiling point is in proportion to the number of molecules present in a given volume of the solution. The dextrose molecule, like the other simple sugars, is half the size of the cane-sugar molecule. Dextrose or any of the simple sugars therefore will have twice the influence in raising the boiling point as the same weight of cane sugar. The rise in the boiling point at the soft-ball stage then would theoretically be twice as great with dextrose alone as with sucrose alone.
On the other hand, corn sirup contains some dextrin, which has a higher molecular weight than sucrose. Sirups made from a glucose sirup high in dextrins may contain fewer molecules per unit of weight than sirups made from sucrose. This would lower the boiling point.
This fact is recognized by professional candymakers. They warn against the danger of cooking candies containing commercial glucose to too high a temperature. The point at which such sirup darkens is about 20° F. below that of a sirup made from granulated sugar.