Michigan
State University Extension
Preserving
Food Safely - 01600549
10/13/97
Because the products contain fruit pulp or pieces of
fruit, they tend to stick to the kettle during cooking and
require constant stirring to prevent scorching.
Wash the fruit and remove the stems and blossoms. Peel
peaches, pears, tomatoes, pineapples and quinces. Then shred
the pineapple after removing the core. For tomatoes, cut
slits and squeeze out the seeds; cut large tomatoes in
quarters and leave small ones whole. Thinly slice pears,
peaches and quinces after halving and coring and/or pitting.
Take the pits from sour cherries. Leave strawberries and
raspberries whole.
With Added Pectin
When powdered pectin is used in making conserves and
marmalades, combine powdered pectin with unheated crushed
fruit. Mix well. Bring to a full boil with bubbles over
the entire surface. Add sugar and boil hard for 1 minute.
Without Added Pectin
Conserves, marmalades and preserves made without added
pectin require longer cooking than those with added pectin.
The most reliable way to judge doneness is to use a
thermometer. Before making the product, take the temperature
of boiling water (212 degrees Fahrenheit at sea level).
Cook the fruit mixture to a temperature 9 degrees
Fahrenheit higher than the boiling point of water. For a
softer product, shorten the cooking time; for a firmer one,
lengthen the cooking time.
It is important to stir the mixture thoroughly just before
taking the temperature, to place the thermometer vertically
at the center of the kettle, and to have the bulb covered
with fruit mixture but not touching the bottom of the
kettle. Read the thermometer at eye level.
If you have no thermometer, cook products made without
added pectin until they have thickened somewhat. In judging
thickness, allow for the additional thickening of the
mixture as it cools. The refrigerator test for jelly may be
used.
Process all these products in a boiling water bath canner.