When you have more blackberries than you can possibly eat, you make jam. My wife made these six one-cup sized (8 oz. or 237 ml) jars of blackberry jam on Tuesday (August 27th), starting from about 1.5 kg (3.3 lb.) of blackberries. The jars look a bit oddly shaped in the photo because it’s a closeup with a wide-angle lens.
- Cook the blackberries for about a half hour, until they have broken down. Strain the cooked blackberries through a wire mesh sieve to remove seeds. You will have to force the blackberries through the sieve with the back of a spoon or ladle. This will reduce the weight of your blackberries by about 1/3 to 1/2.
- Weigh the resulting liquid and add an equal amount of sugar. In this case, there was one kg of blackberries, so she added one kg of sugar. Add lemon juice, about three Tbs. (44 ml) to one kilogram (2.2 lb.) of blackberry liquid. Cook this mixture for an additional half hour; it’ll still be thin, but it’ll thicken when it cools. You don’t need to add any pectin.
- Fill, cover, and seal canning jars following the hot water canning process as outlined in a canning manual.
Blackberry jam is especially good on pancakes in the winter.