How to make Blueberry Rhubarb Jam

Rhubarb's tartness complements the sweetness of blueberries.

The tartness of rhubarb goes well with the sweetness of blueberries to make a perfect pair for jam. Because rhubarb and blueberries are low in pectin, it is important to add powdered or liquid pectin in order for the jam to set. Pectin is found in the skin of many fruits. It's job is to bond cell walls together causing liquid to gel. It also keeps fruit pieces from sinking to the bottom of jam while the liquid sets.

Things You'll Need

• Blueberries
• Food processor or mixing bowl and potato masher
• Cutting board
• Rhubarb stalks
• Large measuring cup
• Stock pan
• Measuring spoons
• Lemon juice
• Sugar
• Mixing spoon
• Teaspoon
• Stockpot
• 10 1/2-pt. jars with lids
• Tongs
• Towel
• Pectin
• Ladle

Instructions

1. Wash the blueberries. Place 8 cups of blueberries in a food processor and use the pulse button to chop it. If you do not have a food processor, place the blueberries in a bowl and them crush with a potato masher.

2. Wash the rhubarb stalks and place them on the cutting board. Chop the rhubarb into 1-inch pieces. Measure 4 cups of rhubarb pieces. Place in stock pan.

3. Measure 2 tbsp. lemon juice to stock pan. Add the crushed blueberries and 4 cups sugar. Place on stove burner and turn heat to high. Continually stir the fruits and sugar until the mixture boils. Use potato masher to break up the rhubarb pieces.

4. Boil the jam for 30 minutes. While the mixture boils, place 10 1/2-pt. jars and the matching lids in a second stockpot filled water and bring to a boil. Boil the jars and lids for 10 minutes. Remove from pot using tongs and set the jars and lids upside down on a dry, clean towel.

5. Turn off burner and move pan off the residual heat. Mix in two packages of liquid or powdered pectin. Stir fully to dissolve and distribute into the jam.

6. Turn the jars right side up on the towel. Ladle the jam into each jar until there is a 1/2-inch gap remaining. Place lids on the jam jars and screw tightly to form a seal. Return the jars to the pan in which you sterilized the jars. Bring to a boil and cook for 10 minutes.

7. Remove the filled jam jars from the boiling water with tongs. Set on the towel and let the jam and jars cool completely. Store in a dark cupboard or pantry.

Tips & Warnings

• Add cinnamon and nutmeg to taste if you want a spiced jam.

• When handling rhubarb, carefully dispose of the toxic leaves. Make sure they are not within reach of pets or children.

References

• Oregon State University: Making Jams, Jellies and Fruit Spreads
• The Science of Cooking: Pectin and Partners for Perfect Preserves
• "Summer in a Jar: Making Pickles, Jams and More"; Andrea Chesman; 1985
• National Center for Home Food Preservation: General Canning Information
• Medline Plus: Rhubarb Leaves Poisoning

Resources

• The Rhubarb Compendium: Rhubarb Jam