Combine the unpasteurized red wine vinegar and red wine in a large crock or jar.

Ensure the container can hold at least 1 gallon, allowing for air circulation.

Cover the opening with a cotton towel or muslin, securing it with a rubber band.

Place the container in a warm spot (68-70F) for 1 to 2 months.

Check and sniff the mixture occasionally.

A distinct vinegar aroma and a slight film (voile) will appear on top.

Avoid moving the jar to prevent disrupting the film, which is the bacteria forming.

After at least 1 month with a vinegar smell, transfer to a crock with a spigot or barrel.

Pour the vinegar, carefully transferring the 'mere' (sediment) by hand.

Draw off one-third of the vinegar and bottle it for use.

Replace the drawn vinegar with an equal amount of red wine.

Add ends of wine bottles to the vinegar, avoiding submerging the 'mere'.

Do not add too much wine at once to prevent harming the 'mere'.

Wait at least 2 weeks after adding wine before drawing off more vinegar.