Friend of mine's family made something which they called 'apple wine': an open bucket with sugar, apple juice, some citrus (lemon juice, I believe) and then lef

Friend of mine's family made something which they called 'apple wine': an open bucket with sugar, apple juice, some citrus (lemon juice, I believe) and then left for about a week. (With muslin over the top to keep the flies off!) Wild yeast causes it to start fermenting. Once it begins to froth, you bottle. After another week or so it's lightly carbonated and very slightly alcoholic. The thing is, it continues to ferment in the bottles. So as time passes, it gets more and more alcoholic and less and less sweet, as the yeast consumes the sugar. So while the children were allowed to drink it for the first few weeks after bottling, after a certain point it was distinctly adults-only. So it's quite possible that the parent simply left theirs to ferment too long. ...I used to make ginger beer, which is a variation on the same thing; you cultivate a yeast/bacteria/ginger culture used for the fermentation rather than relying on wild yeast, but the process is the same. Thing about ginger beer, though, is that it's heavily flavoured with ginger, and you need the sugar to make it drinkable. So if you left it for too long it ended up both extremely alcoholic and mouth-puckeringly bitter. (I can strongly recommend giving ginger beer a try, actually. It's dead easy to make, exceedingly nice, you can pick any alcohol level you like including almost none, and is a continuation of a thoroughly ancient tradition. Be warned, though: (a) it's packed full of sugar, (b) it's quite hard to make in small quantities, and (c) if you get the bug you may find yourself surreptitiously exchanging jam-jars full of biological slime at pubs with total strangers...)