Rinse the berries. Remove the stalks, if still attached.
Place the berries in a pot. Make sure the pot is big enough because the berry mixture will rise during cooking.
Heat the berries on high heat for 8-10 minutes until juice has been released.
Strain the juice through a fine strainer and return the juice to the pot.
Add sugar and simmer the mixture on medoum heat until it thickens, around 10 to 15 minutes.
Remove the foam, if it has formed on the top. Pour while still hot in sterilised jars. Screw on lids, cool the jelly and store in a cool place.