Chapitalization = adding sugar

Never thought we'd need to add sugar to our must, so we needed to get up-to-speed on the art of chapitalization.  Not too surprisingly, we turned to the Web only to get a variety of advice and a mix of good and bad equations on how to figure out how much sugar to add.

My husband is a genius, however, and shared with me that the calculation is "super simple":
1. weigh the fermenter
2. subtract 5 lbs cuz that's what the bucket weighs
3. assume 80% of the weight is juice (this is the dodgy part, i'm just guessing)
4. to get sugar, multiple brix times weight: (0.20 * 84 lbs) = 16.8 lbs in the must
5. to get target sugar: (0.23 * 84 lbs) = 19.3 lbs
6 2.5 lbs = 19.3 - 16.8

Even simpler is to just multiply the difference: (sugar to add) = (target brix - current brix) * lbs of juice.