I really suck at this maths stuff (I normally just get ballpark figures using online calculators), so can someone help here?
Making this year's batch of ginger wine (about 20L). I used about half actual white grape must this time, bought from the local vineyards for a bargain price, rather than using raisins or whatever - figured it CAN'T do any harm! The rest of the bill is sugar. But my calculations are off because of this little experiment - I have gone from 1082 OG all the way to dry, or as near 1000 as makes no odds, which I didn't think would happen. Fermentation is still going strong, so I am happy to keep adding sugar until the yeasties give up, not bothered about a high ABV, and if I go overboard a bit with the sugar it doesn't matter as I plan to "backsweeten" anyway.
But how do I work out my ABV from multiple additions of sugar like this?
E.g. I have gone from
1082 -> 1000
I then add, say 1kg of sugar to take it back up to around 1012. Then, (for example), it ferments back down to 1002 (or maybe it ferments dry again and I add MORE sugar).
How do I work out ABV from that, and is it even possible without getting a bit more involved with the volume, specific gravity of water/sugar etc?
I wouldn't even care that much about ABV, but I part of the batch is for friends, and they will want to know what they are drinking