How to compute alcohol content - Home Brew Forums

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07-12-2005, 08:40 PM   #1
ian

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Jul 2005
Pendleton, SC USA
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I've been reading on this and I can't find a difinitive formula to compute alcoholic content. Its not a big deal. I'm not trying to brew a high alcohol content beer, I was just curious.

I've got a hydrometer and plan to use it this weekend on my first brew but I don't really know how to use it to determine alcohol content.

Thanks,
Ian

07-12-2005, 09:59 PM   #2
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Apr 2005
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Abw = 76.08(og-fg)/(1.775-og)

Abv = Abw (fg/.794).
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07-12-2005, 10:58 PM   #3
rsitzejr
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Jun 2005
Sanford, NC
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Quote:
 Originally Posted by brewhead Abw = 76.08(og-fg)/(1.775-og) Abv = Abw (fg/.794).
I'm pretty lousy at math, so can someone explain this one better?

07-12-2005, 11:02 PM   #4
bikebryan
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Mar 2005
Alexandria, VA
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Quote:
 Originally Posted by rsitzejr I'm pretty lousy at math, so can someone explain this one better?
Just get a copy of ProMash. You can get an eval copy for free. It has a % acohol computer built into it. You just plug in your OG and FG and it does the rest.

07-12-2005, 11:33 PM   #5
cygnus128
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Jun 2005
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Quote:
 Originally Posted by rsitzejr I'm pretty lousy at math, so can someone explain this one better?
Are you looking for a why? The formula looks complicated but it is really just plugging your og and fg numbers in and then calculators away!

07-13-2005, 12:27 AM   #6
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http://www.leebrewery.com/beermath.htm

but you'll still have to know your og and fg and other info
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07-13-2005, 12:40 AM   #7

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Mar 2005
Bakersfield, CA
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The way I've been doing ABV is OG-FG*105

Example: My Scottish Ale--1.085-1.015=.07
.07*105=7.35ABV

I can't remember exactly where I got this but it has seemed pretty accurate.

07-13-2005, 12:52 AM   #8
rsitzejr
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Jun 2005
Sanford, NC
Posts: 65

Quote:
 Originally Posted by AlaskaAl(e) The way I've been doing ABV is OG-FG*105 Example: My Scottish Ale--1.085-1.015=.07 .07*105=7.35ABV I can't remember exactly where I got this but it has seemed pretty accurate.
Now that sounds like what's in "The Joy's of Homebrewing" book.
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07-13-2005, 12:14 PM   #9
ian

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Jul 2005
Pendleton, SC USA
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Quote:
 Originally Posted by brewhead Abw = 76.08(og-fg)/(1.775-og) Abv = Abw (fg/.794).
Ok, please excuse my ignorance but what does Abv stand for?
Also Abw, what does that stand for.

I'm assuming it means Alcohol By Volume or Alcohol By Weight. But, I'm guessing.

07-13-2005, 12:19 PM   #10
kenmc
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Apr 2005
Dublin, Ireland
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ian, thats spot on...