1/2 cup Bragg's unpasteurized apple cider vinegar
3/4 bottle of red or white wine
Pour the vinegar into the wine bottle, close the top and shake well to combine. Remove the top from the wine and set the bottle in a dark place at room temperature.
Shake the bottle to mix and aerate every 4 days. The wine will turn to vinegar in about 3 weeks. Pour 1 cup of this vinegar into a new bottle of wine to continue the process.
Handmade vinegar keeps indefinitely and is a good way to use up unfinished wine.