|Under ripe blackberries||2 1⁄2 Pound (1.1 kilogram)|
|Water||1⁄2 Pint (300 milliliter)|
|Lemons||2 , juiced|
|Sugar||1 Pound (adjust quantity as needed)|
Wash the blackberries and put them in the pressure cooker with the water and lemon juice.
Put on the lid and bring to medium (10 lb) pressure.
Cook for 8 minutes.
Reduce pressure slowly.
Strain the fruit through a jelly cloth or 2-3 thicknesses of muslin.
Measure the extract and put it in the cooker to reheat.
Meanwhile weigh the sugar, allowing 450 g (1 lb) sugar to each 500 ml (just under 1 pint) extract, and warm it.
Remove the cooker from the heat, add the sugar and stir until it is dissolved.
Return the uncovered cooker to the heat and boil the contents rapidly, stirring all the time, until setting point is reached.
Remove the cooker from the heat and allow the contents to settle, then pot and cover.