Making jams, marmalades, preserves, and conserves
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.
- Jams are made from crushed or ground, whole fruit and usually have a thick consistency due to high pectin content.
- Marmalade is a jelly with pieces of fruit suspended in it. Citrus peel and juice are frequently the basis of marmalade.
- Conserves are jams made from a mixture of fruits. They usually contain citrus fruit, nuts, and raisins.
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:
- combined with fruit rich in pectin, or
- 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:
- Large, flat bottom kettles (6-8 quart size)
- Wooden spoons and metal spoons
- Jelly or candy thermometer
- Standard canning jars with two-piece lids
- Boiling water bath canner
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.
Use standard jars with 2-piece lids. Have jars clean and hot. Pack product to within ¼ inch of top, and seal. Heat process for 6 minutes in boiling water bath canner (10 minutes for cold, unsterile jars). Count time from when water returns to boil.
Because of high sugar content, jams, marmalades, preserves, and conserves are mainly a source of calories.
Note: Jelly jars and paraffin are no longer recommended. An incomplete seal with paraffin and the absence of a heat treatment may result in mold growth and toxin production in the jelly. Persons continuing to use the paraffin no water bath method should be aware of the potential health risk.
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 persons on weight control diets.
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.
If you are preparing a jam, conserve, or marmalade with powdered or liquid pectin, be sure to carefully follow the directions accompanying 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.
There is a third method for preparing jams; it 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.
- Strawberry jam without added pectin
- Strawberry jam with liquid pectin
- Freezer strawberry jams recipe
- Orange marmalade recipe
- Tomato preserves recipe
- Plum conserve recipe
- Recipes with no added pectin: Corn syrup may replace ½ sugar, Honey may replace ½ sugar Recipes with added pectin: Corn syrup may replace ½ sugar, Honey may replace ½ sugar
- The jelly is done when 2 big drops slide together and form a sheet that hangs from the edge of the spoon.
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Reviewed by Lou Ann Jopp, University of Minnesota Extension educator, 2010.