Prepare mason jars and lids by washing and sterilizing in boiling water or running through the sterilization cycle on the dishwasher.
Prepare the strawberries and raspberries. Rinse with cool water. Slice strawberries into halves or quarters and then crush them with a potato masher. Crockpot jam cooks best the smaller the pieces are broken down beforehand.
Add sugar, pectin, strawberries and raspberries to the crockpot.
Set the crockpot on high and cook for 2-3 hours, stirring every 30 minutes.
When the sugar is completely dissolved throughout the entire mixture, the jam is done.
Ladle jam into prepared jars, secure lids, and leave the jars to set for 24 hours before storing in the freezer.
If, instead of storing in the freezer, you’d like to process the jars in a boiling water bath, they can be stored on the shelf for up to 1 year.
Jam will keep in the refrigerator up to three weeks and on the shelf for up to 1 year. If jam is not processed in water bath, store in the freezer up to 3 months.
Measure the sugar and fruit accurately. Use “reduced sugar”-specific pectin if you want to use less sugar. It is made specifically for low-sugar recipes. Regular pectin requires the right amount of sugar to gel properly.
Jam cooked in the crockpot sets a bit thinner than jam cooked on the stovetop. 220°F is the ideal temperature at which the sugars and pectin bind together to form a thick jam. Crockpots will vary, but my jam never reached 220°F, even after testing a batch for 6-8 hours. After so much time, the sugars start to caramelize and the jam turns brown and does not taste good.
The best results with crockpot jam are cooking for 2-3 hours and stirring regularly to help distribute the sugar and make sure it all dissolves completely. Even without reaching 220°F, crockpot jam still gels and has a thicker consistency than standard freezer jam. It is perfect for toast, pastries, or topping any of your favorite dishes.
Check that the lids are sealed and secured before storing them on the shelf. Jars that do not seal properly should be stored in the refrigerator.
Crockpot jam is super convenient for making jam in the hot summer months when standing over a hot stove isn’t ideal.