I discovered this recipe in a vintage cookery book. It produces a rich blackberry vinegar ideal for salads and especially beetroot.

1lb (500g) blackberries,

1 pint (500ml) malt vinegar

1lb [500g] granulated sugar for each pint [500ml] of juice

Place the blackberries in a glass preserving jar and add the vinegar. Seal and leave for one week. Squeeze the blackberry mixture and strain the liquid through a fine strainer into a saucepan. Bring to boil and add the sugar, stirring well to dissolve it. Boil for ten minutes then pour into sterilised jars or bottles and seal. This keeps well.

Paul Cleave