You asked about calculating Kcal in beer:
Kcal/12 oz beer:
alcohol w/w X 6.9 = A
real extract - Ash X 4 = B
A + B = C
C X 3.55 X specific gravity = Kcal/12 oz
In the past I used .15 as Ash factor, based on analysis
at time in Frankenmuth, MI.
I hope the forgoing is of help to you.
Boscos Nashville Brewing Co.
THE RESTAURANT FOR BEERLOVERS