NDSU Extension Service - Ramsey County


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Strawberry Season

Strawberry Season


          Whether you are finding them in your garden, a farmers market or the local grocery store – you are certain to find an abundance of strawberries on hand at this time of year. 

          Strawberries are actually not a berry but a member of the rose family.  A strawberry consists of many tiny individual fruits embedded in a fleshy scarlet receptacle. The brownish or whitish specks, commonly considered seeds, are the true fruits, known as achemes.  Each achene surrounds a tiny seed. These berry components make strawberries relatively high in fiber.  Strawberries are also an excellent source of vitamin C, a good source of folate potassium, and are relatively low in calories.      

          Strawberries are a fragile food.  Their optimum storage temperature in the home is 32 degrees to 36 degrees F. The optimum humidity for storage of berries to prevent water loss and shriveling is 90 to 95 percent. Store the fruit in the crisper drawer of your refrigerator.  Keep strawberries packaged in closed plastic clamshell containers or place fruit in a partially opened plastic container bag to maintain high humidity.

           Do not wash berries until just before eating or preserving. Washing will add moisture and will cause the berries to spoil more rapidly. Strawberries can only be stored for up to 7 days under optimum conditions and on how ripe the fruit was when purchased or picked.

          Strawberries are acidic. The pH (measure of acidity) of whole, ripe strawberries ranges from 3.3 to 3.6.  Freezing, drying and making jams and jellies are some of the best ways to preserve strawberries.

          Jams, jellies and fruit spreads are simple and rewarding ways to preserve strawberries. Traditional strawberry jams are sweet spreads made by boiling crushed fruit with sugar until the mixture thickens. Jellies are clear, firm gelled products made with fruit juice and sugar. Pectin, a gelling substance found naturally in fruits, is needed to form a fruit-based gel. Strawberries are low-pectin fruits, so strawberry jam and jelly recipes usually call for added pectin.

          Jam or jelly made with added pectin requires less cooking, retains more natural fruit flavors and generally gives a larger yield.

          Most jams and jellies are preserved by their high sugar content. Sugar is essential for gel formation when you use regular pectin in jam and jelly recipes. However specially modified pectins are now available that can be used to make freezer jams and jam-like fruit spreads with less sugar, with artificial sweeteners or with not sweeteners. If you want to make a low or  no sugar product, follow the directions on the modified-pectin package exactly because any variations in quantities or the order in which you add the ingredients could result in a product that does not gel.  Pectin specifically intended for freezer jam is also available and requires significantly less sugar than traditional jams and freezer jams made with regular pectin.

          All strawberry jams and jellies (except freezer jam) should be processed in a boiling water bath canner. To prevent spoilage, freezer jams must be stored in the freezer or in the refrigerator once a jar is opened .Since strawberries are high-acid (low pH) foods, they do not have the potential to develop botulism but they can spoil due to mold growth. 


Strawberry Rhubarb Jam with Pectin

1 ½ pounds red stalks of rhubarb

1 ½ quarts ripe strawberries

½ tsp. butter or margarine (optional ingredient to reduce foaming)

6 C. sugar

6 ounces liquid pectin


          Wash and cut rhubarb into 1-inchpieces and blend or grind. Wash, stem and crush the strawberries, one layer at a time, in a large saucepan. Add butter, if desired, and sugar thoroughly mixing it into the juice. Bring to a boil over high heat, stirring constantly.  Immediately stir in the pectin. Bring to a full, rolling bill and boil hard one minute, stirring constantly. Remove from heat, quickly skim off the foam and fill into sterile half-pint jars. Leaving ¼ inch of headspace. Adjust lids and rings and process in boiling water bath for 10 minutes. Yields about 7 half-pints.


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