1kg redcurrants
500g strawberries
water (enough to cover pan base)
Sugar (500g per litre)
Citric acid (15g per litre)

Heat the fruit gently in a heavy based pan with just enough water to cover the base of the pan.  Cook gently until the fruit breaks down completely.  Cool in the pan then strain through a jelly bag or muslin. To each litre of juice add 500g sugar and 15g citric acid.  Reheat gently to about 85°C to dissolve the sugar.  Bottle hot to preserve.  To use, dilute to taste.