What formula is correct for calculating alc %? - Page 2 - Home Brew Forums

 Home Brew Forums > What formula is correct for calculating alc %?

06-05-2008, 02:12 AM   #11
Eves
Recipes

Mar 2008
Posts: 382
Liked 4 Times on 4 Posts

Quote:
 Originally Posted by dirtbag um . . . 5 + .5 = 5.5, not 10.
Actually it is 10. Perhaps I need to be more clear:

10% * 5 = 0.5 <- right?

So 5 + .5 = 5.5 that means that the alcohol level increased from 5 to 5.5. Which is an increase of 10%. Now I know .5% doesn't seem like a big increase but when you consider that some people go out of their way to squeeze out a little more ABV without too much impact on their final product it would be nice to know what the true increase of priming is.

As for the Coopers carb drops I see no reason to believe they're lying about them adding .5% ABV. I just question whether or not the use of priming sugar or other brands of carb tabs also increase the ABV by that much.

06-05-2008, 10:05 AM   #12
Kiwi_Jonno
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Feb 2008
New Zealand!
Posts: 194
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Quote:
 Originally Posted by Eves Actually it is 10. Perhaps I need to be more clear: 10% * 5 = 0.5 <- right? So 5 + .5 = 5.5 that means that the alcohol level increased from 5 to 5.5. Which is an increase of 10%. Now I know .5% doesn't seem like a big increase but when you consider that some people go out of their way to squeeze out a little more ABV without too much impact on their final product it would be nice to know what the true increase of priming is. As for the Coopers carb drops I see no reason to believe they're lying about them adding .5% ABV. I just question whether or not the use of priming sugar or other brands of carb tabs also increase the ABV by that much.
Assuming that the Coopers Carb drops carbonate the beer the same amount as priming with sugar, the same alc % should be added surely? The Homebrew Book I read (was a good one) said priming adds 0.3% so perhaps it is more then ya think?

Reading the Coopers formula again... it doesn't state if the priming is using its drops or sugar. It recommends 180g sugar for the 23L or 6gal (us) batch.

And I guess knowing the EXACT % isn't overly important, but I like to know roughly for future batches I guess.

06-05-2008, 12:54 PM   #13
FlyingHorse

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Mar 2007
Evanston IL
Posts: 1,856
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A "typical" priming solution containing 4 oz of corn sugar adds ~11 gravity points to your 5 gallon batch. That's a little over 2 points per gallon.

.002 x 131 = 0.26% ABV
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06-05-2008, 02:34 PM   #14
Shaggy
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Feb 2008
South Side Chicagoland
Posts: 257

Quote:
 Originally Posted by Got Trub? My point was it doesn't really matter. Unlike commercial brewers we don't get taxed based on our production of alcohol so unless you want bragging rights for some triple IPA you brewed who cares? GT
Well, I for one would like to know the approximate strength I'm drinking or serving.
Since taking hydrometer readings is part of my program, doing the quick math to get an estimate is worth it to me and only takes a couple seconds.

I just use the "(OG-FG) x131" method for the approximate strength and leave it at that. I don't worry about priming sugar additions as its minimal in the big picture.

06-05-2008, 02:47 PM   #15
BierMuncher
...My Junk is Ugly...

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Jan 2007
St. Louis, MO
Posts: 12,417
Liked 805 Times on 438 Posts

Quote:
 Originally Posted by Bike N Brew .002 x 131 = 0.26% ABV
Exactly.

Do your "131" calculation and add a 1/4 point if you prime.

I for one want to know the ABV% on all of my beers. There's a big difference between downing a pint of my "Rye-Not a Woody?" IPA at 7.6% and my "Cream of Three Crops" Cream Ale at 3.5%.

06-05-2008, 10:13 PM   #16
niquejim
Burrowing Owl Brewery

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Jul 2007
Cape Coral Florida
Posts: 2,376
Liked 51 Times on 40 Posts

Just go here
http://www.franklinbrew.org/tools/ac.html

no math, no problems