3 cups fresh blackberries
2 cups rice vinegar
2 cups sugar
Process berries in food processor until smooth.
Combine puree and vinegar in bowl and let stand at room temperature for 24 hours. Stir occasionally.
Strain fruit to remove the seeds and add berries to a large saucepan. Stir in sugar and simmer 5 minutes.
Cool and pour into jars with airtight lids or corks. Vinegar lasts several months on your counter.