How strong ? - Home Brew Forums

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12-10-2012, 02:01 PM   #1
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Nov 2012
Posts: 55

Hi all I cannot make out how strong my beer is likely to be ?
My starting OG was 40 ish and looks to be ending at about 15/13 but I'm lost on the math I'm guessing about 3 ? Any help would be great !!

12-10-2012, 02:13 PM   #2
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Apr 2012
Richland, WA
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3.53 abv at 1.013fg
3.27 abv at 1.015fg
Calculated at 1.040 og
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12-10-2012, 02:17 PM   #3
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Nov 2012
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Cheers have you got the method as mine got sanitised at some point and what I found on the Internet made less than no sense

12-10-2012, 02:21 PM   #4
GilSwillBasementBrews

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Jul 2012
Eagleville, Pennsylvania
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(OG - FG ) x 131.25 = ABV%
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12-10-2012, 02:29 PM   #5
unionrdr
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Feb 2011
Sheffield, Ohio
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Or the Cooper's formula I use; (OG-FG)/7.46 + .5 = ABV%.
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12-10-2012, 02:40 PM   #6
gcdowd

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Jun 2011
Baldwinsville, NY
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Some guy dusted off is algebra book and came up with a formula that IMO is fairly accurate, albeit somewhat annoying to remember. I think it's more accurate than the (OG - FG) x 131.25. The only caviat is that you must use the whole number of the gravity reading (i.e. 1.056 is just 56 in the formula). Anyway the formula is below:

((832+OG) * (832+FG) * (OG-FG)) / 5,500,000 = ABV

For instance:
OG = 1.060
FG = 1.010

832+60 * 832+10 * 50 / 5,500,000
892*842*50 / 5,500,000
37,553,200 / 5,500,000 = 6.8% ABV

12-10-2012, 02:51 PM   #7
unionrdr
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By the Cooper's formula,I got 7.2%. Close anyway. The formula (OG-FG) x 131.25 gave me 6,562.5. Moving the decimal point 3 places left would give 6.56%.
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12-10-2012, 04:57 PM   #8
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Nov 2012
Posts: 55

7.2 sounds way high for a London ale

My final was 1.01 with a starting of 1.04
So I'm reckoning that 3.92 abv is closer

So bottled half and easy kegged the other half
Just hope it's drinkable come Christmas

12-10-2012, 05:10 PM   #9
unionrdr
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Sheffield, Ohio
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I was going by the example OG1.060,Fg1.010. Your numbers-by Cooper's-4.52%, By the (OG-FG) x 131.25 formula-3.94%.
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12-10-2012, 05:24 PM   #10
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Nov 2012
Posts: 55

Cheers I still think under 4 sounds more likely

But anything s possible I over hopped if that's possible