Place blackberries in a large bowl or bucket. Pour on boiling water and mash blackberries with rolling pin or allow to cool then mash by hand. Leave the must for 3 days and stir daily. Now strain the blackberry must through a wine bag until all juice has been extracted. Make up a sugar syrup with the sugar and 1 litre (1¾ pints) of water and boil until the sugar has dissolved. Add the blackberry juice and sugar syrup to a gallon jar. Grate the orange and lemon rind, squeeze the juice of the fruits and add this to the jar and make up to 4.5 litres (1 gallon) with cooled, boiled water. Add the yeast. Use a cotton wool bung and leave for a few days, then fit an airlock and leave to ferment for at least 3 months. Siphon into a clean gallon jar and leave for another 6 months. It should then be ready to bottle and sample.
Recipe from Jenny Stone. I found that I needed a little pectinol to clear this wine.