Wash the apples and cut them into small pieces, including the peels and cores.
Place the apple pieces in the glass jar, filling it about three-quarters full.
Stir the sugar in the water and pour it into the jar to cover the apple pieces completely.
Insert fermenting weight (optional but works best, in my experience). Cover the jar with a fermenting lid, piece of cheesecloth or coffee filter and secure it with a rubber band.
Store the jar in a cool, dark place for about two weeks, stirring every days.
After two weeks, strain out the apple solids. Return the liquid to the jar and cover it again with the lid, cheesecloth or coffee filter.
Allow the jar to sit for an additional four to six weeks, stirring occasionally. Taste the vinegar periodically until it reaches your desired acidity level. Once ready, transfer the vinegar to a clean bottle or jar and store it at room temperature or in the refrigerator.
ACV is good for 1-2 years and the tastes continues to improve with age.