What you’ll need
- Crushed strawberries, raspberries, blueberries or blackberries
- Sugar
- Fruit pectin
- Canning jars with self-sealing lids
- Boiling water canner
step 1: Understand Jam
The difference between jellies, jams, preserves and marmalades and fruit butters lies in the consistency of the finished product and the amount of fruit in the mixture. Jam is made from crushed fruit and sugar. It is not as solid as jelly, but is relatively thick.
Jams and jellies require four things, in the right combination, to achieve proper texture: fruit, pectin, acid and sugar. The fruit provides the flavor and color. Pectin, in combination with the acid, is what allows the fruit and fruit juice to gel. And the sugar acts as a preservative, provides flavor and helps with the gelling.
Most commercially available pectin products include recipes on or in their packaging that define the right combination of fruit, sugar and pectin for maximum success when using that product. You should follow those recipes when making your jam. The following are general steps of the jam-making process.
step 2: Pick the Berries
Pick ripe strawberries, blueberries, blackberries, raspberries or whatever berries you want to make the jam. The berries should be fully ripe, but not mushy.
Put the berries in a shallow container as you are picking to avoid crushing those on the bottom.
step 3: Wash and Crush the Berries
Put berries in a colander and rinse under cold water. Never soak berries in water as they can become waterlogged. Gently blot berries dry with a paper towel.
Remove stems and leaves and crush the berries. Berries with a lot of seeds, like blackberries and raspberries, can be heated until they are soft then pressed through a sieve to remove most of the seeds.
step 4: Combine the Berries, Sugar and Pectin, and Heat
Bring slowly to a boil, stirring occasionally until the sugar is dissolved. Once the sugar is dissolved, boil rapidly, stirring frequently, until the mixture thickens. Overcooking may break down the pectin and prevent proper gelling.
step 5: Pour into Jars and Process
Pour the hot jam into hot, sterile, canning jars. Leave about ¼ inch of empty space at the top of the jar. Clean the jar’s lip with a damp towel and add the lids. Put the jars in the boiling water canner and process about 5 minutes or as appropriate for your altitude.
Keep in mind that most recipes are for specific jar sizes. If you use jars that are too large, the jam may not gel correctly.