ABV aftering adding honey post-fermentation

[rwps1971]

I'm looking for help calculating the abv in my latest brew. I brewed 5 gals of Kolsch almost two weeks ago and added honey after fermentation. Below are my readings, how would you calculate this? Is it as simple as adding together two percentages (4.8 + 1.2)?

OG 1.049
Gravity after 4 days 1.012
Added 1 lb honey and gravity bumped to 1.018
9 days later I'm at 1.009

Thanks for the help!

 

[Calder]

You are correct, it is that simple, but you don't have to take intermediate measurements.

1 lb of honey has about 33 gravity points. It varies between 30 and 36. That is, in 1 gallon of water it will give a gravity of 1.033.

1 lb in 5 gallons will change the gravity by 33/5 or .0065. This is what you got going from 1.012 to 1.018.

The easiest way to account for the addition of the honey is to add it's contribution to the OG; 1.049 + .006 = 1.055, and work the abv out from there.

So going from 1.055 down to 1.009 will give you and abv of 6.0%

 

[rwps1971]

Thanks for taking the time to reply. Adding .006 to the OG makes perfect sense. I appreciate the feedback.