How do I calculate abv if I'm going to brew a margarita beer

[requiem960]

I'm going to brew a margarita beer for mid-spring to early summer.

Abv is estimated at 4.2% on the beer alone. Let's say I hit that number and at kegging I put in 12 ounces of 40% abv tequila and 16 ounces of Triple Sec at 30% abv. How in the world do I calculate the final abv?

I hope I'm in the right section, because the math seems science, but abv could fall under fermentation. Either way, I would love some help calculating correctly!

 

[kev211]

Wow thats a lot of triple sec. Me thinks you're gonna have a sweeeet beer. But to answer your question, your beer will be raised to 5.4% ABV with those additions (assuming its a 5 gallon batch)

 

[stpug]

((640oz*4.2%)/668oz) + ((12oz*40%)/668oz) + ((16oz*30%)/668oz) = 5.46% ABV

This assumes you will have 5 gallons of beer you're doing this to:
5 Gallons of beer is 640oz
5 Gallons + 12oz + 16oz is 668oz

0.0402395209580838+0.007185628742515+0.007185628742515=0.0546107784431137 (or 5.46% ABV)

Edit: You can simplify the math with this:

(640oz*4.2%) + (12oz*40%) + (16oz*30%)
------------------------------------------   =   5.46% ABV
                 668oz

 

[kev211]

((640oz*4.2%)/668oz) + ((12oz*40%)/668oz) + ((16oz*30%)/668oz) = 5.46% ABV

This assumes you will have 5 gallons of beer you're doing this to:
5 Gallons of beer is 640oz
5 Gallons + 12oz + 16oz is 668oz

0.0402395209580838+0.007185628742515+0.007185628742515=0.0546107784431137 (or 5.46% ABV)

Thanks for posting the math. I did mine on a post-it and had to go into a meeting and didnt have time to post haha

 

[requiem960]

Thanks for doing the math! And the triple sec should yield me about 6.1 ounces of sugar. I'm using it to keg condition! Yeah, it'll probably be a little on the sweet side, and produce a few hangovers. But, why not?

Brewing a gose, and will also keg sour with lactic acid and salt it during the last ten minutes of the boil with pink Himalayan. Both the salt and acid may mellow out some of that sweetness. I'm interested to play around with this recipe, and hope I don't wind up with a five gallons of rough drinking beer! But, if it comes out anywhere close to what's going on inside my head, this'll be a fun beer to drink on Cinco de Mayo!