Does anybody know how to accurately track the calories in a batch of homebrew. Haven't seen any discussion threads on this issue. It's a topic most people will not care about but if there's anyone out there who knows the science I think this would he an interesting thread.
#1: Most calories come from alcohol content. Yes, there are unfermentable sugars but those can contribute 10-20% or so.
#2: My easy-and-quick estimate (and calculators are useful of course, even though many of them are somewhat problematic - put in 1.000 as final gravity as a check, for example):
If you use Plato: 1 calorie per Ounce per Plato (taken from original gravity).
For example, 12 oz of 10 Plato (1.040) beer is 120 calories.
22 oz bottle of imperial stout of 25 Plato (1.100 or so OG) is about 600 calories. etc.
If you are used to SG - 4 gravity points are about 1 calorie per oz. So 12 oz of 1.040 beer is 12*10=120 calories.
If you are more used to ABV:
5% abv, 12 oz have about 150-160 calories. It's about the same as a can of coke, which, also at 12oz, is about 138 calories, but apparently bacteria in your gut will consume about 20% of alcohol before you can digest it, so they are about equivalent.
Adjust up or down depending on actual ABV - of course unfermentable sugars may contribute to calories but not ABV.
Beer is much better for you than coke, of course.
Finally, don't get me started on the whole "beer gut" and "miller lite" misinformation. Counting calories is perhaps one of the reasons we have 4% ABV, tasteless crappy commercial beers (which are still about 100 calories even if fermented super-dry).
I would rather eat chocolate cakes paired with 10% ABV imperial stouts.
