Photograph: Jonathan Gregson
Tip the blackberries into a freezer bag and freeze until solid.
Mix the frozen fruit, sugar and cloves in a bowl, then spoon into a sterilised 1-litre preserving jar.
Top up with the vodka. Seal the jar and store the blackberry vodka in a cool, dark place for 3 months – give it a shake now and then, every day if you can, for the first week or two.
After 3 months, strain the cloves and fruit from the vodka and discard; return the flavoured vodka to the jar.