This whole efficiency thing htconfuses the hell out of me. I brewed Slims Graham Cracker Ale 2.0 found here, http://www.homebrewtalk.com/f78/slim...-2-0-a-342443/
. My numbers are as follows
BIAB system. I had to sparge with one gallon of water to get to my preboil volume of 6.5 gallons.
Pre boil 6.5 gallons 1.047 using refractometer, no sugar added or bakers chocolate added
Pre Boil 6.5 gallons 1.061 with the 1lbd of brown sugar and bakerís chocolate
Post boil 5.5 Gallons 1.073 using refractometer.
Not sure which numbers to use in order to calculate my efficiency.