ABV Calculation?

Northern Brewer General
1

How do you calculate ABV when you add additional fermentables during secondary fermentation?

I just made a 1.050 wheat beer that finished at 1.008 or 5.5% ABV. Then I added 3# (5 cups) of Vintner’s Harvest Peach Puree (SG 1.043) as a secondary. The finished beer is again at 1.008? I guess because there are more solids along with the additional alcohol, the net change in apparent attenuation is zero? Does this sound correct? So what is the ABV of this beer?

2

By 1.043 SG for the Peach Puree, do you mean 43 PPG (points per gallon)? This seems about right, so I’ll give you an answer based on that.

I used Brewer’s Friend

so you can try this out yourself. First, I added enough DME to make the OG 1.050. Then, I added 3 pounds of a custom ingredient with 43 PPG. This gave an OG of 1.076.

So, your OG is 1.076, your FG is 1.008, and this gives an ABV of 8.9%.