Many areas don't have access to certain types of vinegar, necessitating some cooks to make their own. Some foodies are convinced that store-bought vinegar doesn't compare to homemade. When vinegar is produced, a thick skin is formed inside the liquid. This is called the mother. It is removed when the vinegar is done, and used to start another batch. The mother holds the live, active ingredients that produces a batch of vinegar. If you don't want to start another batch immediately, you can store the mother for later use.
Skim the mother out of your vinegar with a slotted spoon and place it into some sort of open container. An earthenware crock is a good choice.
Cover the crock with a cheesecloth. This will keep dust and debris from falling in, yet allow air to enter. The mother needs air to stay alive.
Store the crock in an area where the temperature will stay in the 60 to 90 degree range. If the temperature drops below 60 degrees or above 90, it could die.
Symptoms that the vinegar mother died include a darker color and increased density.