My goal here is to start with apples and go in a two step process toward making apple cider vinegar.
This is the more scientific approach. The first step is an anaerobic process (in the absence of oxygen) where yeast is going to convert the sugars in the apple juice into alcohol while belching carbon dioxide.
I divided the apple juice in two. In one jug, I added yeast. In the other, I’ll just let any yeast that was on the apples do their thing.
One would expect the yeast-supplemented batch will ferment faster and yield more alcohol than the natural one.