Rebel Brewer Giveaway!
 Home Brew Forums > Calculating ABV with added booze?

 LinkBack Thread Tools Display Modes
12-14-2011, 11:49 AM   #1
sivdrinks
Senior Member
Feedback Score: 0 reviews

Recipes

Join Date: Apr 2011
Location: Lebanon, PA, PA
Posts: 786
Liked 3 Times on 3 Posts

 Calculating ABV with added booze?

Not sure how to do it. Added 8oz of 80 proof Jim Beam Black to the secondary of an 8.4ABV Imperial Stout, 5 gallons. Any ideas?

__________________

12-14-2011, 12:52 PM   #2
bomberman
Feedback Score: 0 reviews
Recipes

Join Date: Oct 2011
Location: Middlebury, VT
Posts: 91
Liked 1 Times on 1 Posts
Likes Given: 9

A quick search turned up this formula:

(Beer Volume(oz) * Beer ABV %) + (Liquor Volume(oz) * Liquor ABV %) / (Beer Volume + Liquor Volume)

If I'm doing this right in your case it would be

(640 * .084) + (8 * .40) / (640 + 8) = 0.0879.. so about 8.8%

Hope that helps. Now this may be a stupid question, but what would be wrong with taking another gravity reading after adding it and simply recalculating the ABV? I figure that would work unless the extra alcohol somehow messes with the reading.

__________________

Last edited by bomberman; 12-14-2011 at 01:07 PM. Reason: math error!

12-14-2011, 05:38 PM   #3
sivdrinks
Senior Member
Feedback Score: 0 reviews

Recipes

Join Date: Apr 2011
Location: Lebanon, PA, PA
Posts: 786
Liked 3 Times on 3 Posts

Ya lost me on the math there. The beer is already bottled, took over three months to carb! Guess I should have taken another reading before bottling.

__________________

12-14-2011, 06:09 PM   #4
theveganbrewer
Feedback Score: 1 reviews
Recipes

Join Date: Sep 2011
Location: Beaverton, OR
Posts: 1,927
Liked 283 Times on 204 Posts
Likes Given: 263

Sounds about right. He just calculated the percentage for the whole batch. Each bottle will be about 8.8%.

__________________

-Retired Homebrewer

12-14-2011, 06:18 PM   #5
sivdrinks
Senior Member
Feedback Score: 0 reviews

Recipes

Join Date: Apr 2011
Location: Lebanon, PA, PA
Posts: 786
Liked 3 Times on 3 Posts

K, did it. Came up with 10.17. Thanks!

__________________

12-14-2011, 06:19 PM   #6
sivdrinks
Senior Member
Feedback Score: 0 reviews

Recipes

Join Date: Apr 2011
Location: Lebanon, PA, PA
Posts: 786
Liked 3 Times on 3 Posts

Quote:
 Originally Posted by theveganbrewer Sounds about right. He just calculated the percentage for the whole batch. Each bottle will be about 8.8%.
Now I'm lost again.
__________________

12-14-2011, 06:23 PM   #7
theveganbrewer
Feedback Score: 1 reviews
Recipes

Join Date: Sep 2011
Location: Beaverton, OR
Posts: 1,927
Liked 283 Times on 204 Posts
Likes Given: 263

(640 * .084) + (8 * .40) / (640 + 8) = 0.0879.. so about 8.8%

That was for your specifications. The only reason is I'm doing the same recipe right now and I've come to 8.8 as well. How did you get 10.17?

__________________

-Retired Homebrewer

12-14-2011, 06:28 PM   #8
sivdrinks
Senior Member
Feedback Score: 0 reviews

Recipes

Join Date: Apr 2011
Location: Lebanon, PA, PA
Posts: 786
Liked 3 Times on 3 Posts

My bad, disleksic. You're right, thanks again!

__________________

12-14-2011, 06:35 PM   #9
SenorPepe
Feedback Score: 0 reviews
Recipes

Join Date: Feb 2011
Location: Madison, WI
Posts: 690
Liked 18 Times on 15 Posts
Likes Given: 20

Very timely thread for me. Thanks, folks.

__________________

12-14-2011, 06:55 PM   #10
29thfloor
Feedback Score: 0 reviews

Recipes

Join Date: Feb 2011
Location: Pt. Pleasant, PA
Posts: 258
Liked 6 Times on 6 Posts
Likes Given: 3

Quote:
 Originally Posted by bomberman Now this may be a stupid question, but what would be wrong with taking another gravity reading after adding it and simply recalculating the ABV? I figure that would work unless the extra alcohol somehow messes with the reading.
That gravity reading wouldn't do you any good because you're comparing it to the OG reading which was before the additional alcohol was added.

__________________
29thfloor.com/blog
Twitter | Facebook | 29thfloor on Instagram
Primary: Blonde Lambic (Aug 2012)
Secondary:
Kegged: Belgian Milk Stout, Double Wit
Bottled: Berliner Weisse, Oaked Tripel Brett, Dawson's Kriek, Sweet Mead, Trois Pistoles Clone

 Quick Reply Message: Options Quote message in reply?
 Thread Tools Display Modes Linear Mode

FOLLOW US ON