Blackberry Jam
Ingredients
Directions
Prepare
Weigh the blackberries and put them in a pot.
Cook the fruit
Boil without sugar.
Mash the blackberries with a potato masher.
Boil the mashed blackberries slowly for about 30 minutes.
Remove most of the boiling juice.
Add sugar and finish
Add the sugar.
Cook for another 30 minutes.
Pack the jam into pint jars.
Transcribed from a scanned cookbook and modernised for today's kitchens. Where the book gave no heat or time, or said "a moderate oven", the temperatures and times here may be modern equivalents rather than the book's own figures.
Explore the science
What each ingredient does
- Blackberries
- Provide the fruit, natural pectin and flavor that the jam is built from.
- Sugar
- Sweetens the jam and helps it thicken and keep.
The step that matters
Cook for another 30 minutes after adding the sugar. The sugar must fully dissolve and the mixture must keep boiling so the pectin and sugar can set the jam. Undercooking leaves it runny, while overcooking can scorch it and darken the flavor.
“What each ingredient does” and “The step that matters” were written by Claude from this recipe’s own method and reviewed in samples by CompKitchen.
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