You need the cooking/crab apples and lemon in this Blackberry Jelly Recipe as, at best, blackberries have only medium pectin and acid content and the late ones are decidedly lacking in both.
Have some pectin stock at hand in case it fails the pectin test.
Ingredients for Blackberry Jelly:
- 4 lbs (1.8 kg) blackberries
- 1 lb (450 g) cooking or crab apples
- Juice of 1 lemon
- 1¼ pints (1 litre) water
- ¾ lb (338 g) sugar per pint of juice obtained.
Method for Blackberry Jelly:
- Wash and wipe the apples, cut into quarters, but do not remove the skin or core.
- Wash and drain the blackberries and pick over to remove any unsound fruit and stalks.
- Put the apples into a pan with the water and lemon juice and stew until pulpy.
- Add the blackberries and continue stewing until the blackberries are soft.
- Test for pectin.
- Turn into a jelly bag and leave overnight to strain.
- Measure the juice and heat in a pan.
- Add ¾ lb (338 g) warmed sugar to each pint of juice, stirring until all the sugar has dissolved.
- Bring to the boil and boil rapidly until the jelly sets when tested.
- Remove the scum.
- Pot and seal whilst still hot.
General Information on Making Jelly Preserves