There seem to be still plenty of blackberries on the bushes despite the rather erratic weather we've been having. There isn't too much rocket science involved in jam-making, except that you need to make sure that you use enough sugar to preserve the fruit. I quite like to add the fruit in two stages so you are left with some good chunks to spread on your toast or dollop on your rice pudding.
2kg blackberries, rinsed
1kg preserving sugar
Put the preserving sugar into a heavy-based saucepan pan or preserving pan with a cup of water. Cook over a medium heat, stirring every so often until the sugar has melted then continue cooking for another 5 minutes. Add half of the blackberries and cook on a medium heat for 30 minutes, stirring every so often. The mixture should be a fairly thick, sauce-like consistency by now and the blackberries will have disintegrated.
Add the rest of the blackberries and continue cooking on a medium heat for 15 minutes. Remove from the heat and spoon a thin layer of the jam on to a plate and place in the fridge. If the mixture sets (after about half an hour), the jam is ready to ladle into sterilised jars and seal the lids; if not continue boiling for another 5-10 minutes.
Store in a cool place for up to 6 months.