It isn't. Everything depends on quantity and quality. Kefir and kvass - do have alcohol for example. Low ammounts but it is there. Not to mention dry red wine

It isn't. Everything depends on quantity and quality. Kefir and kvass - do have alcohol for example. Low ammounts but it is there. Not to mention dry red wine and such. Drink a bottle day a you will have problems. Drink 100ml every now and then and you will be the same as before.