How to measure ABV

[davidabcd]

Hello everybody!

I've been measuring the ABV with the (OG-FG) X 131.25 equation believing I was somewhere in the ballpark. I also am aware that the formula becomes less accurate with higher ABV beers. I do not know what constitutes the low end of a high ABV beer.
My recent beers have 8# of DME and 3# of table sugar.
My OG has been consistent for many batches at 1.104 and the FG has been consistent at 1.004.
There's the Brewers Friend calculator that has two options, one is the above (I think) and there's an "Alternate" option. Does anyone know, for a fact, if that "Alternate" calculator is accurate for high ABV beers?
If not, is there a way I can get fairly close to measuring my ABV accurately?

Thank you very much.

 

[marc1]

Hello everybody!

I've been measuring the ABV with the (OG-FG) X 131.25 equation believing I was somewhere in the ballpark. I also am aware that the formula becomes less accurate with higher ABV beers. I do not know what constitutes the low end of a high ABV beer.
My recent beers have 8# of DME and 3# of table sugar.
My OG has been consistent for many batches at 1.104 and the FG has been consistent at 1.004.
There's the Brewers Friend calculator that has two options, one is the above (I think) and there's an "Alternate" option. Does anyone know, for a fact, if that "Alternate" calculator is accurate for high ABV beers?
If not, is there a way I can get fairly close to measuring my ABV accurately?

Thank you very much.

There's a link on the Brewer's Friend ABV calculator page that explains the difference. The alternate one is an attempt to model higher gravity beer ABVs more accurately. It also explains why you might choose one model over the other and what the limitations are. (Over 6% the alternate equation starts providing more different results).

https://www.brewersfriend.com/2011/06/16/alcohol-by-volume-calculator-updated/

 

[Tobor_8thMan]

BeerSmith calculates 13.5% ABV

 

[davidabcd]

BeerSmith calculates 13.5% ABV

Thanks, the OG-FG X 131.25 gets me to 13.125 and then I add a titch for the 3/4 C priming sugar. My big question is, how accurate am I being?

 

[davidabcd]

he alternate one is an attempt to model higher gravity beer ABVs more accurately.

Thanks! I did see that "alternate" equation. My question is, is that attempt accurate? I don't know how the pros do it. I will say, the beers are eye-crossingly strong. It leads me to believe that they are at least 13.5 if not a point or two higher.

 

[VikeMan]

Thanks! I did see that "alternate" equation. My question is, is that attempt accurate? I don't know how the pros do it. I will say, the beers are eye-crossingly strong. It leads me to believe that they are at least 13.5 if not a point or two higher.

FWIW, one pro brewer I know sent some high ABV beers for lab testing and the ABVs came back much closer to the traditional formula than the "alternate."

 

[marc1]

This thread, especially post #6:

https://www.homebrewtalk.com/threads/how-do-commercial-breweries-measure-abv.416472/

 

[davidabcd]

FWIW, one pro brewer I know sent some high ABV beers for lab testing and the ABVs came back much closer to the traditional formula than the "alternate."

That's really good to know. When I input the numbers in the OP, I get 15$% plus ABV.
I always appreciate the input from the people here with experience.