Blackberries get sooooooo black in jam! Or just the deepest darkest purply black. I used a little balsamic vinegar in this recipe to get the taste of this one step out of Peter Rabbit’s nursery . . .
Pour 6 cups of blackberries into a jam pan.
Add the zest of 2 clementines, the juice of 2 clementines (the same two, so zest them first . . .) and the juice of 1 lemon. Add 2 teaspoons of balsamic vinegar.
Add 2 teaspoons of calcium water (Pomona Pectin) to the berries.
I added 1 1/2 cups of sugar first to the berries to get them to simmer down and release their juice. Sometimes blackberries can be quite stubborn!
At this point, depending on the seediness of your berries, I recommend straining out the seeds from approximately half the berries. I just hold a strainer over the jam pan, scoop up the bubbling brew and press it through with a spoon. I continue this until the seeds disappear from prominence . . .
You’ll add the last cup of sugar with pectin powder last, stir briskly, let it come to a boil for 1-2 minutes, and then check for sheeting.
This makes about 5 cups of jam, so pour into sterilized half pints and process in a hot water bath for 15 minutes at 5000 feet.
Balsamic Blackberry Jam
6 cups blackberries
zest and juice of 2 clementines
juice of 1 lemon
2 teaspoons balsamic vinegar
2 teaspoons calcium water
2 1/2 cups sugar, divided 1 1/2 and 1 cup portions
1 teaspoon pectin powder