— Written By N.C. Cooperative Extension

Strawberries are now ripe for the picking, which kicks of the annual canning season with homemade strawberry jams. Start this year’s canning season out correctly for safe and delicious products by following several important steps when making jams and jellies.

Select good quality fruit. The fruit should be just at the ripe stage (not under ripe or over ripe) for best natural color and flavor. Fruits of irregular size and shape can be used as long as they are of good quality, since they will be cut up, mashed or made into juice.

Canned or frozen fruit or fruit juice can be used to make jellied products. If you use commercially canned or frozen products, select those that have no added sugar. Because commercial canned or frozen products are made from fully ripe fruit (which are lower in pectin than under-ripe fruit), pectin must be added.

If you can or freeze your own fruit or fruit juice, use some slightly under ripe fruit (usually ¼ slightly under-ripe and ¾ fully ripe is recommended). Then if the fruit naturally contains adequate pectin, none will have to be added to products made from that juice. Can fruit in its own juice. Do not add sugar, or if you do, note on each jar how much sugar it contains.  Then you can allow for that sugar in the jelly recipe.

Pectin. Pectin is the substance that causes the fruit to gel. Some fruits have enough natural pectin to make high quality products. Others require added pectin, especially when they are used for making jellies, which should be firm enough to hold their shape. The highest quality pectin is found in just-ripe fruit. Pectin from under-ripe or over-ripe fruit will not form a gel.

Commercial pectins are made from apples or citrus fruit and are available in both powdered and liquid forms. Be sure to follow the manufacture’s directions or tested recipes when using commercial pectin. The powdered and liquid forms are not interchangeable in recipes. 

Commercial pectin may be used with any fruit. Many consumers prefer the added pectin method for making jellied fruit products because fully ripe fruit can be used, cooking time is shorter and is set so there is no question when the product is done, and the yield from a given amount of fruit is greater. However, because more sugar is used, the natural fruit flavor may be masked.

            Acid. Acid is needed both for gel formation and flavor.  The acid content varies among fruits and is higher in under-ripe fruits. When fruits are low in acid, lemon juice or citric acid may be used.

Sugar. Sugar is an important ingredient in jellied fruit products. It must be present in the proper proportion with pectin and acid to make a good gel. Sugar is the preservative for the product, preventing the growth of microorganisms. It also contributes to the taste of the product.  Never cut down on the amount of sugar a recipe calls for unless syrup is the desired end result.

Granulated white sugar is usually used in homemade jellied fruit products. Sweeteners such as brown sugar, sorghum and molasses are not recommended since their flavor overpowers the fruit flavor and their sweetness varies. Light corn syrup or light, mild honey can be used to replace part, but not all, of the sugar. For best results, use tested recipes that specify honey or syrup. Artificial sweeteners cannot be substituted for sugar in regular recipes because the sugar is needed for gel formation.

Amount to prepare. To have jellied fruit products at their best, make up only the quantity that can be used within a few months. They lose flavor, lose their bright color and turn darker during storage. Double batches do not gel properly – you will end up with a syrup consistency.

Important food safety reminders when preparing soft spreads:

Do not use the “inverted method” to seal jars – although this method is sometimes listed on manufacturer instructions, it is not a recommended practice in North Carolina due to the high humidity. Process jams, preserves, marmalades, conserves, fruit butters, honeys and syrups in a Boiling Water Bath for the length of time specified in the recipe.

Do not seal jelly products with paraffin wax. Over time, paraffin wax begins to pull back from the sides of the jar, creating openings where mold and yeast can enter and contaminate the product. Also, paraffin can catch on fire if overheated. If you detect mold growth, throw out the entire contents. Always seal jars of jelly products with a two-piece canning lid.

Throw out moldy jelly products.  Simply removing the mold from the surface of the jelly is not enough. The mold has a “root” system that cannot be seen. Therefore, there is no way to be sure you have removed all mold by looking at the product. Mold might cause allergic and respiratory problems for mold-sensitive individuals.

Storage.  It is essential that jellied products, especially jelly, be allowed to sit undisturbed for 12 hours after they are made. Moving them could break the gel. After the jellied products have cooled for 12 hours, check the seal; remove the screw band, label and store in a cool, dry, dark place.

Linda Minges is a registered dietitian with the North Carolina Cooperative Extension Service (  You can contact her for more information on nutrition and food safety at 704-922-2127 or by email at