Background: A couple of years ago we left a half drunk bottle of Sirah on the counter and it went to vinegar. A really nice vinegar with a pleasant, mild flavor, and we've been using splash here and a bit there ever since. Now I'm down to circa half a cup.
Is this a live culture like a bread starter? Can I buy a bottle of a similar wine, and intentionally propagate the flavor of this stuff? Or is just a crap-shoot?