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Jams and Jellies

Making jams, marmalades, preserves, and conserves

William Schafer and Isabel D. Wolf

Jams, marmalades, preserves, and conserves are fruit products which are preserved by sugar. These products differ in the degree of gel attained, manner of preparation of fruit, and ingredient composition. They are easily made at home.


Fruit gives the product its special flavor and often provides pectin for thickening.

Pectin is needed to provide thickening or gel formation. Pectin is formed from a parent compound, protopectin, during the ripening of fruit and during the cooking of underripe fruit. All fruits contain some pectin. Apples, crabapples, gooseberries, some plums, highbush cranberries, and citrus peel contain large amounts of pectin. Other fruits like blueberries, strawberries, cherries, or huckleberries contain little pectin and give thick jams, marmalades, and conserves only if:

  1. combined with fruit rich in pectin, or
  2. combined with powdered or liquid pectin.

Acid. Sufficient acid must be present for gel formation in marmalades and thickening in jams and conserves. For fruits lacking in natural acid, like strawberries, it is provided by lemon juice or other citrus fruit. Commercial pectin products contain organic acids, like fumaric acid, which increase the acid content of fruits which lack acid.

Sugar aids in gel formation, develops flavor by adding sweetness, and acts as a preservative in jams, marmalades, preserves, and conserves. Corn syrup or honey can replace part of the sugar in these fruit products. Use light colored, mild-flavored honey. If you substitute too much honey, it can overpower the fruit flavor.


The following equipment may be needed:

Filling jars and heat processing

A research study conducted at the University of Minnesota demonstrated that heat processing jelly for 5 to 15 minutes had no harmful effect on the products. Those tested included ones made with liquid and powdered pectin, as well as traditional no-pectin-added ones. In addition, the heat processing gives a better seal, and destroys mold that may be present on the top surface of the product.

Recommended procedure

Use standard jars with 2-piece lids. Have jars clean and hot. Pack product to within ΒΌ inch of top, and seal. Heat process in boiling water bath canner according to the chart below. Count time from when water returns to boil.

Processing chart.

Because of high sugar content, jams,
marmalades, preserves, and conserves
are mainly a source of calories.

Note: Paraffin wax is no longer recommended for sealing jars. An incomplete seal with paraffin and the absence of a heat treatment may result in mold growth and toxin production in the jelly. Using paraffin with no water bath is a potential health risk.

Nutritive value

Because of high sugar content, jams, marmalades, preserves, and conserves are mainly a source of calories. One level tablespoon of these products contains 55 to 70 calories and should be used sparingly by people concerned about controlling their weight or sugar intake.

Methods of preparation

The two main methods for preparing jams, conserves, and marmalades are by cooking fruit and sugar with no added pectin and with added pectin.

No added pectin

Jams, conserves, and marmalades; made without added pectin require longer cooking and have a slightly different flavor from those with added pectin. They also yield a less finished product.

The product is done when the temperature reaches 220° – 222° F.

Added pectin

If you are preparing a jam, conserve, or marmalade with powdered or liquid pectin, be sure to carefully follow the directions that come with the pectin product. The order of combining ingredients depends on the type of pectin used.

Successful preparation of pectin-added jams, marmalades, and conserves depends on accurate timing. Begin counting time when the mixture reaches a full rolling boil -- one that cannot be stirred down.

A third method for preparing jams does not require cooking the fruit. This product must be stored in the refrigerator or freezer.

Directions for making jams by three methods, one method for marmalades, preserves, and conserves, follow.

illustration of spoons dripping with jam
  1. Recipes with no added pectin: Corn syrup may replace ½ sugar, honey may replace ½ sugar
  2. Recipes with added pectin: Corn syrup may replace ½ sugar, honey may replace ½ sugar
  3. The jelly is done when 2 big drops slide together and form a sheet that hangs from the edge of the spoon.


Revised by Suzanne Driessen 2016

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