Priming Sugar and ABV Question

[sremed60]

This has probably been discussed a thousand times... BUT!

When I've created recipes on BeerSmith II I always click the drop down menu and choose "Corn Sugar" under Carbonation, but I have never actually added that corn sugar to the ingredients list.

I'm putting together a patersbier recipe which figured out to 4.4 abv. I decided to add 0.325 lbs of corn sugar to the ingredient list and clicked the button "Add after boil." Adding that 5 oz of priming sugar to a 5.5 gallon batch bumped the abv up from 4.4 to 4.8.

I know abv is usually based on apparent extract and not real extract and all that, so it's just a ballpark figure anyway. I was just interested in getting some input from more experienced brewers.

 

[Gerhardt]

You are adding more fermentables so you will boost the ABV of the final product, though it may be slight. If you want to do the calculations yourself you certainly can and actually calculate the volume of alcohol added exactly by the additional fermentation. Are you using sucrose, dextrose, or something else to prime?

Just did my stoichiometry again. 1g of glucose yields 0.647mL of alcohol.
ABV is volume alcohol/total volume of beverage.

So: Additional ABV = (m x 0.647)/V
m=mass of glucose in grams
V=total volume of beverage in mL
Dextrose (D-glucose) is just an isomer of glucose so use your grams dextrose.

0.325lbs=147.4g
(147.4x0.647)/20,819.8=0.00458 -OR- 0.46% increase

So BeerSmith II is pretty accurate.

 

[AZCoolerBrewer]

I figured out that the corn syrup/priming sugar is about .5% depending on how much you use to carbonate. And now I'll take the opportunity to share a picture of my happily well carbonated "Two Hooters" American Amber Ale. It came out great with a juicy hop flavor and subtle nose. Very crisp, clean and dangerously drinkable at 7.2%ABV. The .5% coming from priming with table sugar. Cheers!

 

[sremed60]

Yeah, I've always used corn sugar. I knew it had to add to the end abv, but I guess I just figured the amount it added was so negligible I never worried about adding it into the final calculations. So I take my last gravity reading and then rack to the bottling bucket and add the priming sugar.

I decided to add it in on this one just because the abv was so low and I wanted to try and keep it low. It actually surprised me that it boosted the abv 0.4% I have a tripel sitting in secondary right now that is 8% and I plan on using 7 oz of dextrose to carbonate to 3.5. Obviously it'll be a bit more that 8% when it's ready.

 

[AZCoolerBrewer]

In my poring over HBT and other resources I found that the weakest of commercial bottles are tested to 3 volumes, so make sure you get the thicker walled bottles for that brew.