��������

How to Make Berry Jam

For this home-style recipe, you simply need equal parts berries and sugar. Skip the fruit pectin. Though it helps jam solidify, it can also dilute the natural flavor of the fruit. You may need to cook the fruit a bit longer, but it’s worth it for that old-fashioned taste. 

Today, we used boysenberries grown in our community garden. However, any soft fruit will do, including raspberries, blackberries, boysenberries, blueberries, strawberries, peaches, apricots, nectarines, or even rhubarb. Extra points if you grow your own!

Image: Boysenberries—which resemble red blackberries (and, are, in fact a cross of several types of berries).

The berries were frozen last season and we had to make room in the freezer for this year’s crop. In fact, we made this jam right in the old garden shed, with an electric cooktop!

Note: This recipe does not involve processing with a hot water bath as you would with a larger (or commercial) canning project. We are, however, placing the jars and lids in a pot with boiling hot water (while the berries cook). Then, you must put your finished jam in the refrigerator—or freeze this jam. 

Ingredients and Materials

• The night before, defrost fresh berries if they’re frozen in the refrigerator. If you have a blueberry bush or love to have blueberries around, you can freeze your blueberries and use them in jam whenever you want!
• Put a small plate (on its own) in the freezer to chill.
• Have clean glass jars and lids on hand. We used small jars to sell at a school fair.
• We had about 4 pounds of berries and used almost the same amount of sugar.

If you don’t want to make such a large batch, use the following recipe, which measures by cups:

• 4 cups berries
• 4 cups granulated sugar
• YIELD: Makes 4 cups.

Note: You can use one-third less sugar, but you do need sugar for the jam to gel properly.

Directions: How to Make

• Put the clean berries in a large stainless steel pot. Bring to a full, steady boil over high heat until the berries reduce and there aren’t any large lumps left. (There is no need to include water while boiling, as the berries have plenty of moisture themselves.) Stir consistently to prevent sticking and scorching. 

Image: Boiling the berries on the stovetop.

• Weigh the sugar and add to the berries or, alternatively, add the measured sugar in a steady stream. Keep stirring until sugar is dissolved. Tip: If you feel the bottom of the pot and it’s “crunchy” with sugar, then it’s not ready.

Image: Weighing the sugar and adding to the pot.

• Now bring the mixture to a rolling, bubbling boil on the highest heat. Add a thermometer, if you have one, to ensure that the temperature is as far above boiling point as possible. Some cooking thermometers have a “jam” marking (8°F above the boiling point of water). Once the boiling mixture has reached the correct temperature, then your jam should set. 
  Note: For each 1000 feet of altitude above sea level, subtract 2 degrees F. For instance, at 1,000 feet of altitude, the jelly is done at 218°F; at 2,000 feet, 216°F, etc.

Image: Checking that the temperature is high enough for jam making (220°F).

• While the jam is cooking, sterilize the glass jars and lids in boiling water.
• Tip: To determine when the jam is ready, do the “wrinkle test.” Take the cold plate out of the freezer and spoon a teaspoon of berry liquid on the plate and let it set up for several minutes. Push your finger against the liquid. Is it thick enough to wrinkle? If so, the cooked jam has reached a setting point.

​
Image: Doing the cold plate test! We keep a cold plate in the garden shed mini-fridge just for jam making.

• Remove the berry jam from the heat. Allow to cool for 10 minutes. Pour the cooked berry mix into your hot sterilized jars.

Image: I am pouring the jam into each of our gift jars for our community garden’s Christmas fundraiser.

• Place the lids on the jars at once and twist them tightly. You may hear the jar “snap” or seal as it cools. After the jam cools, refrigerate your jars and use within 1 to 2 weeks or freeze them up to 6 months, according to USDA guidelines.
   
• Also Note: USDA guidelines for food safety recommend a boiling-water bath for high-acid foods. If you are going to store the jam for a longer period, it’s advisable to put the jars through a boiling-water bath for 10 minutes. This recipe is for jam that you’ll be eating immediately! See our Guide to Water-Bath Canning.

Image: My small batch of berry jam jars, ready to put in the refrigerator or freezer.

After making this jam, I had to take a couple home for my family. The next morning, we were ready to spread pure boysenberry goodness on our morning toast. Do you think my taste tester liked the homemade jam?

For more canning and jam-making tips and recipes, see How to Make Jams and Preserves. Also see our Canning Guide for Beginners to find more recipes!

Do you make jam at home? Share your tips in the comments below!