Happy HolidaySs Giveaway - Winners Re-Re-Re-Re-Re-Drawn - 24 hours to Claim!

Get your HBT Growlers, Shirts and Membership before the Rush!

 Home Brew Forums > Post-carb ABV?
02-07-2013, 02:24 AM   #1
codyjack
Feedback Score: 0 reviews
Recipes

Join Date: Jan 2013
Posts: 17
Liked 1 Times on 1 Posts

 Post-carb ABV?

I was wondering if there is a way to find ABV after carbonation. I know the calculation for finding it post-fermentation, but I want to know my alcohol content after the priming sugar is converted. I would imagine the carb would throw off any gravity readings, so how is this accomplished? For example, in my primary right now is a hefeweizen with an OG of 1.040. I plan to bottle at 1.010 and prime with sucrose. The ABV before priming should be around 3.9-4.0%. How can I determine the additional alcohol produced from the sucrose? Or is it a negligible amount?

__________________

02-07-2013, 02:26 AM   #2
b-boy
Feedback Score: 5 reviews

Recipes

Join Date: Jun 2011
Location: The Frozen Tundra, NY
Posts: 2,840
Liked 583 Times on 413 Posts
Likes Given: 162

Pull a sample and let it sit until the CO2 is gone. Then you can get an accurate FG reading.

__________________

Never underestimate the potential of someone who refuses to act their age.

02-07-2013, 02:28 AM   #3
Dirty25
Feedback Score: 0 reviews
Recipes

Join Date: Jul 2012
Location: Mackenbach, Germany
Posts: 227
Liked 12 Times on 11 Posts
Likes Given: 26

I just added 5oz of corn sugar to one of my recipes in Ibrewmaster and it bumped the alcohol up .2 points

__________________

02-07-2013, 02:36 AM   #4
Psych
Feedback Score: 0 reviews
Recipes

Join Date: Mar 2011
Location: Kelowna, BC
Posts: 769
Liked 34 Times on 31 Posts
Likes Given: 30

Take a sample pre-adding priming sugar, then take one POST adding primary sugar, and calculate the difference. Assuming all priming sugar is eaten by the yeast, giving you carb, you should have your difference.

02-07-2013, 03:05 AM   #5
gstrawn
Feedback Score: 0 reviews
Recipes

Join Date: Jun 2011
Location: Athens, Ga
Posts: 374
Liked 22 Times on 16 Posts

It is basically negligible. I can't even remember its 4 oz for priming? Equals 112 grams / 342 g/ mol of sucrose= about 0.3 mols x 46 g/ mol= ~15 grams/ ~19 liters= less than 0.01% by weight and even less for alcohol by volume as the density of ethanol is less than that of water. Not precise math but you can see its negligible.

Hope that helps!

__________________

 Quick Reply Message: Options Quote message in reply?