In order to make jelly, fruit juices must contain two
substances, acid and pectin, and these should be present in
proper proportion. When fruit is cooked, pectin is formed
by the action of water and heat on a substance called
pectose which is present in the raw fruit. This pectose is
closely related to cellulose 1 and probably is closely asso-
ciated with it in the cell walls of the fruit. It is absolutely
unlike cellulose, however, in its property of being affected
by boiling water. The pectin which is obtained from the
pectose is the substance which gives texture to our jellies.
It is possible to make jelly by great concentration without
the addition of any sugar at all to the fruit juice, but the
jelly that is formed is tough and gummy and not palatable,
as well as being much less in amount than is produced
ordinarily. The addition of sugar in the presence of the
1 Cellulose is the chief substance of which the cell-walls of
plants are composed.
16 FOOD STUDY
right amount of acid seems to precipitate the pectin and
make the jelly set.
Not only does one fruit differ from another in the amount
of these two substances which it contains, but different
lots of the same kind of fruit may differ materially. As
fruit ripens it contains less acid, and less pectin as well,
and over-ripe fruit may fail to jelly at all. Fruit that is
not fully ripe is much safer to use than that which is over-
ripe. Some fruits contain too much acid, unless they are
diluted with water, but it is quite possible to add so much
water that there is neither enough pectin nor enough acid
present. As a rule, very juicy fruits need have only
sufficient water added to prevent burning. When they
are soft enough to mash easily, the whole is transferred
to a cheesecloth bag wrung out of hot water, and the juice
is allowed to drip through. If the pulp is squeezed, the
resulting juice is not so clear, but the flavor is not changed.
Less juicy fruits must be covered with water while they
are cooked. The alcohol test for pectin may be relied
upon to tell whether the proper concentration is obtained.
The amount of sugar used, like the water, varies with
the kind of fruit. It is better to err on the side of
using too little, rather than too much. Jelly made from
currants and grapes that are rather green may have as
much as one part of sugar to one part of juice, but, in
general, three-quarters of the amount of the juice is the
right proportion of sugar. If at any time the alcohol test
does not show plenty of pectin, lessen the amount of sugar.
Too much sugar not only will give a jelly which is very
sweet, but may give one that is syrupy. The amount of
acidity can, perhaps, be as well judged by taste as in any
other way. Before the sugar is added, the fruit juice
should be distinctly tart.
Jelly can be made from fruits that are lacking in acid
PRINCIPLES OF JELLY-MAKING 17
by the addition of some acid of vegetable origin, such as
tartaric or citric. This does not always improve the
flavor. The acid is commonly added by stewing with
such fruits some other fruit which will supply the lack-
ing acid.
Food study
1917Page 12
Presented as published in 1917. 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
In order to make jelly, fruit juices must contain two substances, acid and pectin, and these should be present in proper proportion. When fruit is cooked, pectin is formed by the action of water and heat on a substance called pectose which is present in the raw fruit. This pectose is closely related to cellulose 1 and probably is closely associated with it in the cell walls of the fruit. It is absolutely unlike cellulose, however, in its property of being affected by boiling water. The pectin which is obtained from the pectose is the substance which gives texture to our jellies. It is possible to make jelly by great concentration without the addition of any sugar at all to the fruit juice, but the jelly that is formed is tough and gummy and not palatable, as well as being much less in amount than is produced ordinarily. The addition of sugar in the presence of the
1 Cellulose is the chief substance of which the cell-walls of plants are composed.
right amount of acid seems to precipitate the pectin and make the jelly set.
Not only does one fruit differ from another in the amount of these two substances which it contains, but different lots of the same kind of fruit may differ materially. As fruit ripens it contains less acid, and less pectin as well, and over-ripe fruit may fail to jelly at all. Fruit that is not fully ripe is much safer to use than that which is overripe. Some fruits contain too much acid, unless they are diluted with water, but it is quite possible to add so much water that there is neither enough pectin nor enough acid present. As a rule, very juicy fruits need have only sufficient water added to prevent burning. When they are soft enough to mash easily, the whole is transferred to a cheesecloth bag wrung out of hot water, and the juice is allowed to drip through. If the pulp is squeezed, the resulting juice is not so clear, but the flavor is not changed. Less juicy fruits must be covered with water while they are cooked. The alcohol test for pectin may be relied upon to tell whether the proper concentration is obtained.
The amount of sugar used, like the water, varies with the kind of fruit. It is better to err on the side of using too little, rather than too much. Jelly made from currants and grapes that are rather green may have as much as one part of sugar to one part of juice, but, in general, three-quarters of the amount of the juice is the right proportion of sugar. If at any time the alcohol test does not show plenty of pectin, lessen the amount of sugar. Too much sugar not only will give a jelly which is very sweet, but may give one that is syrupy. The amount of acidity can, perhaps, be as well judged by taste as in any other way. Before the sugar is added, the fruit juice should be distinctly tart.
Jelly can be made from fruits that are lacking in acid
PRINCIPLES OF JELLY-MAKING 17
by the addition of some acid of vegetable origin, such as tartaric or citric. This does not always improve the flavor. The acid is commonly added by stewing with such fruits some other fruit which will supply the lacking acid.