Choose a liquid with sugar or alcohol, such as apple juice, wine, cider, or beer
Pour the liquid into a clean glass jar or crock
Cover the container with cheesecloth or a breathable cloth and secure it with a rubber band
Leave some air space at the top of the container
Keep the container in a warm, dark place
Add a little raw, unfiltered vinegar with “the mother” if you want to speed up fermentation
Let the liquid sit undisturbed for several weeks to several months
Taste it periodically until it becomes sour enough
Strain out any solids if needed
Transfer the finished vinegar into a clean bottle
Seal and store it in a cool, dark place