Clean all the stalks from the berries and put them in a pan with the water and lemon juice. Bring to the boil and then simmer for 45 minutes, stirring from time to time. Strain the pulp through a jelly bag overnight. Discard the pulp and measure the juice – for every 600 ml (1 pint) add 450 g (1 lb) of sugar – and heat gently until it comes to the boil. Continue to boil rapidly until a really firm setting point is reached (try it on a saucer). Pour the jelly into small moulds such as an ice-cube maker and leave to set. The end result is a stiff, delicately flavoured jelly that can be cut with a knife and served with coffee after dinner.