Add enough dry coconut to the jar to fill it to within 1-inch of the rim of the jar. Pour in vinegar to cover the coconut, then use a clean spoon to gently push down on the coconut to pack it down. Lay a square of parchment on the jar rim. Position the lid over it, then lower the ring and screw it tightly in place. Shake vigorously then put in a cool, dark place for a week. Once a day, open the jar, replace the parchment square, put the lid back in place, then shake firmly again.

After 7 days, line a sieve or colander with a double layer of fine cheesecloth or butter muslin and position it over a large bowl or liquid measuring cup. Pour the contents of the jar into the lined sieve. Gently press the coconut with a sturdy spoon to squeeze as much liquid from it as possible. Reserve the coconut for other uses in a tightly covered jar in the refrigerator.

Pour the strained vinegar into a sterile jar or glass bottle with a tight fitting lid. This can be stored at room temperature for up to 6 months. For longer storage, keep in the refrigerator.