By Julie Garden-Robinson, Food and Nutrition Specialist

NDSU Extension Service

Earlier this summer, we invited our Extension Service agents to campus for an intensive, hands-on workshop about home food preservation. They learned about the latest recommendations for making jams and salsa, freezing food, pressure-canning vegetables and drying food. They, in turn, share the information and training with the residents in their counties.

We divided the agents into small groups and distributed recipes for jelly and jam, salsa and several other foods. More than one group wanted to be in charge of making raspberry jam because, as a reward for their efforts, they were able to take their homemade jams and jellies home.

As they prepared the various jellies and jams and then loaded the jars into boiling-water-bath canners, I thought about a call I received a few years ago. My caller was quite upset because several jars of her home-canned raspberry jam had literally flipped their lids, spewing sticky raspberry jam throughout her pantry.

Before she called, she had been scrubbing the jam from her pantry walls. One of the jars popped open while we visited on the phone. She was not happy.

She asked why this had happened and how to prevent it in the future. I learned that she had used a recipe formulation that was still valid, and she was using two-piece lids, not paraffin wax, to seal the jars. This was consistent with what we recommend.

As we visited, we figured out the likely reason for the mess in her pantry. Turns out, the recipe she was using did not recommend boiling the filled jars of jam in a water-bath canner for a specified time (usually five minutes).

Her old recipe called for inverting the jars. However, the U.S. Department of Agriculture has recommended a boiling-water bath process for jams and jellies for many years. Since her lids had sealed, she thought she would be enjoying homemade jam in the winter.

Why did this happen? If microorganisms are not deactivated by sufficient heat for the right length of time, some can produce gas in an airtight container. Some organisms can produce enough gas to blow the lids off jars.

The boiling-water bath processing of jams and jellies also prevents mold growth (until the jar is opened) and ensures a tight seal.

Although water-bath canning is safe for acidic foods, such as jellies and pickles, vegetables, such as beans and peas, require a pressure canning process.

I advised my caller to wear rubber gloves and use a disinfectant during the cleanup because we were not exactly sure what organism was responsible. I didn’t hear from her in subsequent years, so I hope she didn’t give up on making jellies and jams

Making jams and jellies is a good entry point into home food preservation. It’s fairly straightforward with a tasty end product.

Typically, jams and jellies are made of fruit/juice, pectin, acid and sugar. Fruit provides the flavor and color and, in some cases, naturally provides the pectin or gelling agent. Apples are an example of a fruit naturally high in pectin, but many apple jelly recipes still require the addition of a commercial pectin product. Raspberry jam always requires the addition of pectin.

You can find various types of pectin in the canning section of grocery stores or other businesses that sell home-canning supplies. Be sure to use the type of pectin called for in the recipe because you cannot substitute powdered pectin for liquid pectin.

Acid also is needed for making jams and jellies. Some fruits, especially underripe ones, are naturally acidic, but some recipes call for lemon juice if the fruit is not sufficiently acidic. Sugar is found in most jams and jellies, but some low-sugar or sugar-free recipes using specialized versions of pectin are available.

To learn more about making jam and jelly at home, contact your local Extension office or check out the materials on www.ag.ndsu.edu/pubs/preservation.html. On this site, you will find free how-to publications titled “Jellies, Jams, Spreads,” “Jams and Jellies from Native (Wild) Fruits,” and “Jams and Jellies from North Dakota Fruits.” You also will find information about freezing food, making salsa and pickles and pressure canning low-acid foods.

Fresh bread or muffins with homemade jam or jelly is hard to beat. Here’s the raspberry jam recipe that was one of the hits of our workshop.

Raspberry Jam

5 c. raspberries and juice

7 c. sugar

1 box powdered pectin

Half-fill water-bath canner with hot water; place it on the stove and let it come to a boil while preparing jam.

Crush the raspberries with a potato masher. Mix the raspberries and pectin and heat to boiling, stirring constantly.

Add the sugar all at once and stir until dissolved. Continue stirring gently until the mixture comes to a full rolling boil that cannot be stirred down. Start timing for one minute and stir constantly while it continues to boil.

Remove from heat. Skim any foam from the jam, and carefully ladle the jam into clean jars using a canning funnel. Fill jars to within 1/4 inch of the rim. Wipe the rim with a clean, damp cloth. Quickly apply the lid and fasten with a ring. Process for 10 minutes (when water begins to boil again, start timing) in a boiling-water bath.

Makes eight half-pints. Each 1-tablespoon serving has about 45 calories, 0 grams (g) of fat, 0 g of protein, 12 g of carbohydrate, 0 g of fiber and 0 milligrams of sodium.

(Julie Garden-Robinson, Ph.D., R.D., L.R.D., is a North Dakota State University Extension Service food and nutrition specialist and associate professor in the Department of Health, Nutrition and Exercise Sciences.)

NDSU Agriculture Communication – July 28, 2011