Mixing Experiment Help; What's my ABV?

[GoldDiggingBrewer]

I brew these clone recipes for Stone all the time, and I recently came up short on a 3gal all-grain batch for the Pale Ale. So I started up a new 3gal batch from extract to mix-in (w/ extra fermentables), aiming to bring the beer up to proper ABV% of 5.5% (pale ale) or 6.9% (IPA). I married them in the secondary with dryhopping.

I'm currently at around 6.1% ABV, and the original Pale ale batch was only coming in at 4.3%. I'm happy with that result if my math is correct.

My Combined Beer ABV Formula:
OG + OG / 2 = Combined OG
Combined OG - Combined FG x 131.1 = ABV%

 

[smizak]

Your equation is correct, assuming identical volumes of beer.

 

[GoldDiggingBrewer]

thanks.