Originally Posted by alexcider
right so i would fill the jar hing up with my cider then float the hydrometer in it then but on all the ones i have seen have like 900 or like 990 on side how do u work this out for a % for your achoal
First, you need to make sure you read from the specific gravity scale - the 900 or 990 you are refering to is really 0.900 or 0.990.
To calculate your ABV - you need two readings - an original gravity before fermentation (OG) and a final gravity when fermentation is COMPLETELY done (FG). ABV = (OG - FG)x129
So, if your OG is 1.050 and your FG is 0.990, your ABV = (1.050 - 0.990) x 129 = 7.74%