State University Extension
Preserving Food Safely - 01600546
The biggest problem in making jelly without added pectin
is to know when it is done. It is particularly important
to remove the mixture from the heat before it is
overcooked. Although an under-cooked jelly can sometimes
be recooked for a satisfactory product, there is little
that can be done to improve an overcooked mixture. Signs
of overcooking are a change in color and the taste or odor
of caramelized sugar.
When cooking jelly, remember that it should be boiled
rapidly, not simmered.
Three methods that may be used for testing doneness of
jelly made at home are described below. Of these, the
temperature test probably is the most dependable.
TEMPERATURE TEST: Before cooking the jelly, take the
temperature of boiling water with a jelly, candy or
deep-fat thermometer (212 degrees Fahrenheit at sea
level). Cook the jelly mixture to a temperature 8 degrees
Fahrenheit higher than the boiling point of water. At that
point, the concentration of sugar will be such that the
mixture should form a satisfactory gel.
Because the boiling point at a given altitude may
change with different atmospheric conditions, the
temperature of boiling water should be checked shortly
before the jelly is to be made. The bulb of the
thermometer must be completely covered with jelly and not
touching the pan.
SPOON OR SHEET TEST: Dip a cool metal spoon in the
boiling jelly mixture. Then raise it at least a foot
above the kettle, out of the steam, and turn the spoon so
the syrup runs off the side. If the syrup forms two drops
that flow together and fall off the spoon as one sheet,
the jelly should be done.
REFRIGERATOR TEST: Remove the jam mixture from the heat.
Pour a small amount of boiling jam on a cold plate and put
it in the freezing compartment of a refrigerator for a few
minutes. If the mixture gels, it is ready to fill.