Abv% after bottles carb?

[woody34]

Does the carbonation process increase the abv% of beer? Seems like it should or does table sugar not give off alcohol when fermented?

 

[BrewinHooligan]

For average carbonation, there is an increase of approximately .4% abv give or take.

 

[dantose]

I'd actually guess that the 0.4% figure it high. some back of the napkin calculations give me about half that.

Let's try some better figures and see. 5 oz priming sugar is 142g. I can't seem to find exactly what kind of sugar priming sugar is, but I'd guess glucose which is 180g/mol. So that's .79 moles of sugar. That yeilds 1.58 mol of ethanol or 73 grams (mw of 46g/mol). 800g/l density gives us .09 liters. Divided by a total volume of 60 liters, that's 0.15% increase in abv

 

[BrewinHooligan]

Priming sugar is corn sugar (dextrose). Adding 5oz dextrose into brewing software gives me an increase of .4% abv on a 5.5 gallon batch. I trust software more than napkin math.

 

[kaconga]

My brewing software gave me .2% abv increase for 5oz of corn sugar in a 5 gallon batch.

 

[BrewinHooligan]

It must vary based on the recipe/yeast because I went through several of my recipes and came up with varying results between .2%abv and .4%abv

 

[dantose]

Priming sugar is corn sugar (dextrose). Adding 5oz dextrose into brewing software gives me an increase of .4% abv on a 5.5 gallon batch. I trust software more than napkin math.

Dextrose is glucose. .4% abv would give 192 grams of ethanol. That's greater than the mass of the 5 oz of priming sugar people normally use. Conservation of mass makes .4% impossible.

EDIT: Stupid english units. I flubbed on the gal to liters conversion. +0.47% abv would be right for the maximum theoretically possible increase for 5 oz in a 5 gal batch.

 

[unionrdr]

you also have to remember that there are about 8 different formulas out there,& each gives a different number. Cooper's formula of (OG-FG)/7.46 + .5 = ABV is the highest. My brain cells tell me it's pretty darn close.

 

[Calder]

5 ozs corn sugar ~11 gravity points. If added to 5 gallons with no volume increase, it would increase the effective gravity by .0022. Assuming it completely ferments it would result in ~.3%

BUT ....... we usually dilute it in water before adding it. If we diluted 5 ozs in 1 pint the added priming solution would have a gravity of 1.088. If you added it to a beer with a OG of 1.088, you would get next to zero increase in abv (yes I know sugar ferments completely, so there would be a small increase). If you added it to a wort with an OG of 1.044, you would increase the abv by about 0.15% (maybe 0.2% since the sugar ferments completely).