Step 1

Wash the berries and place in a bowl. Lightly crush with a potato masher to start extracting the juices

Step 2

Pour the sugar over and stir. Cover the bowl with cling film and place in the fridge for 48 hours, stirring every 12 hours or so to make sure all of the sugar gets dissolved

Step 3

When ready, the fruit should be swimming in a glistening syrup. Drain the syrup and save the fruit for a dessert

Step 4

Pass the syrup through muslin cloth or a very fine sieve into a sterilised jar or bottle

Step 5

Stir the vinegar into the syrup (ensuring the spoon you use is also sterilised)

Step 6

Cover or seal and leave for at least 72 hours before tasting