Making Jams and Jellies
General Information on Jams, Jellies, and Marmalades
Sweet spreads are a class of foods with many textures, flavors, and colors. They all consist of
fruits preserved mostly by means of sugar and they are thickened or jellied to some extent.
Fruit jelly is a semi-solid mixture of fruit juice and sugar that is clear and firm enough to hold its
shape. Other spreads are made from crushed or ground fruit.
Jam also will hold its shape, but it is less firm than jelly. Jam is made from crushed or chopped
fruits and sugar. Jams made from a mixture of fruits are usually called conserves, especially
when they include citrus fruits, nuts, raisins, or coconut. Preserves are made of small, whole
fruits or uniform-size pieces of fruits in a clear, thick, slightly jellied syrup. Marmalades are soft
fruit jellies with small pieces of fruit or citrus peel evenly suspended in a transparent jelly. Fruit
butters are made from fruit pulp cooked with sugar until thickened to a spreadable consistency.
For proper texture, jellied fruit products require the correct combination of fruit, pectin, acid, and
sugar. The fruit gives each spread its unique flavor and color. It also supplies the water to
dissolve the rest of the necessary ingredients and furnishes some or all of the pectin and acid.
Good-quality, flavorful fruits make the best jellied products.
Pectins are substances in fruits that form a gel if they are in the right combination with acid and
sugar. All fruits contain some pectin. Apples, crab apples, gooseberries, and some plums and
grapes usually contain enough natural pectin to form a gel. Other fruits, such as strawberries,
cherries, and blueberries, contain little pectin and must be combined with other fruits high in
pectin or with commercial pectin products to obtain gels. Because fully ripened fruit has less
pectin, one-fourth of the fruit used in making jellies without added pectin should be underripe.
Caution: Commercially frozen and canned juices may be low in natural pectins and make
soft textured spreads.
The proper level of acidity is critical to gel formation. If there is too little acid, the gel will never
set; if there is too much acid, the gel will lose liquid (weep). For fruits low in acid, add lemon
juice or other acid ingredients as directed. Commercial pectin products contain acids which help
to ensure gelling.
Sugar serves as a preserving agent, contributes flavor, and aids in gelling. Cane and beet
sugar are the usual sources of sugar for jelly or jam. Corn syrup and honey may be used to
replace part of the sugar in recipes, but too much will mask the fruit flavor and alter the gel
structure. Use tested recipes for replacing sugar with honey and corn syrup. Do not try to
reduce the amount of sugar in traditional recipes. Too little sugar prevents gelling and may
allow yeasts and molds to grow.
Jams and jellies with reduced sugar
Jellies and jams that contain modified pectin, gelatin, or gums may be made with noncaloric
sweeteners. Jams with less sugar than usual also may be made with concentrated fruit pulp,
which contains less liquid and less sugar. See Guide 7 of the USDA Complete Guide to Home Canning for recipes.
Two types of modified pectin are available for home use. One gels with one-third less sugar.
The other is a low-methoxyl pectin which requires a source of calcium for gelling. To prevent
spoilage, jars of these products must be processed longer in a boiling-water canner. Recipes
and processing times provided with each modified pectin product must be followed carefully.
The proportions of acids and fruits should not be altered, as spoilage may result.
Acceptably gelled refrigerator fruit spreads also may be made with gelatin and sugar
substitutes. Such products spoil at room temperature, must be refrigerated, and should be
eaten within 1 month.
Even though sugar helps preserve jellies and jams, molds can grow on the surface of these
products. Research now indicates that the mold which people usually scrape off the surface of
jellies may not be as harmless as it seems. Mycotoxins have been found in some jars of jelly
having surface mold growth. Mycotoxins are known to cause cancer in animals; their effects on
humans are still being researched.
Because of possible mold contamination, paraffin or wax seals are no longer
recommended for any sweet spread, including jellies. To prevent growth
of molds and loss of good flavor or color, fill products hot into sterile
Mason jars, leaving 1/4-inch headspace, seal with self-sealing lids, and
process 5 minutes in a boiling-water canner. Correct process time at higher
elevations by adding 1 additional minute per 1,000 ft above sea level.
If unsterile jars are used, the filled jars should be processed 10 minutes.
Use of sterile jars is preferred, especially when fruits are low in pectin,
since the added 5-minute process time may cause weak gels. To sterilize
empty jars, see page
Methods of making jams and jellies
The two basic methods of making jams and jellies are described in Guide 7. The standard method, which does not require added pectin, works best with fruits naturally high in pectin. The other method, which requires the use of commercial liquid or powdered pectin, is much quicker. The gelling ability of various pectins differs. To make uniformly gelled products, be sure to add the quantities of commercial pectins to specific fruits as instructed on each package. Overcooking may break down pectin and prevent proper gelling. When using either method, make one batch at a time, according to the recipe. Increasing the quantities often results in soft gels. Stir constantly while cooking to prevent burning. Recipes are developed for specific jar sizes. If jellies are filled into larger jars, excessively soft products may result.
This document was adapted from the "Complete Guide to Home Canning," Agriculture
Information Bulletin No. 539, USDA, revised 2009.
Reviewed November 2009.
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