I understand what you mean UR, but my apple wash had a real smell and taste of vinegar. The flies where really on it. And fermentation wasn't finished at all.
So agree with you, my other washes are "acid" but not at a point to smell vinegar in the entire cellar!
Apple cider vinegar is very expensive here.
Just kidding - move it out of your fermentation area, let it complete the process and use it as vinegar.
Kill the flies they're the culprits which spread the bacteria.
Expect a skin (bacterial mat) to grow on the vinegar. Leave it open to the air as oxygen is necessary to the process.
If you want to speed up the process build a column packed with woodwool and keep pouring the liquid through the column. The bacteria will attach to the wood fibres and there will be plenty of air for the reaction to convert alcohol to acetic acid.