Alas, I am sure this may be a "stupid question," but I am not educated enough on the subject of making wine to know if it is even a valid question or not, let alone know the answer.
In October I started my first batch of wine, using Concorde Grape juice. All went well as far as I could tell: fermentation was robust and protracted, and eventually it ceased after a month or so. I have kept the air lock on, and it has sat still ever since after one racking at the end of October.
Now I wish to know--- how does one know if the wine is good or bad? That is, how does one know if it has turned to vinegar? I have no idea what it is supposed to taste like. I can tell it is alcoholic, and that all of the sugar is gone (it is "dry" as far as I can tell), though I do not know the alcohol content (I broke my hydrometer in October) nor do I know if it tastes the way it should.
I will probably bottle it in a day or two and take a sample to the "Yeast Herder's Gatherum" at Dragonfest in August and ask someone to taste it for me.
I followed what I believe to be the correct steps, as I have outlined in my two videos: