title_body: How long does Chouchen keep once opened?
upvoted_answer: I had to look up Chouchen as I'd never heard of it before (see, after many years still learning!) It looks like it's a form of mead made out of Buckwheat honey which gives it that dark color and probably stronger flavor. According to the article, it was originally made out of cider and honey but it looks like both versions are called Chouchen now. I looked around on the internet and saw that they were generally 13-14% ABV which is in the normal strength for wine and mead. Mead, cider and wine all can last many decades. But as with all of them, once the bottle is opened it will go bad within a few days from oxidation.