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Old 02-09-2013, 11:40 PM   #1
grovedude
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Default Confusion in calculating my ABV

Totally newbie question here - and I've even tried searching for the answer but nothing has done the trick. (Maybe I am dense?)

I am trying to calculate my % ABV, and failing. So I took photos in the hope that someone here could teach me.

The photo (which I am going to try to attach here) shows before and after.

Before = minutes before I pitched the yeast
After = 7 days later when I racked it

This is an experimental brew- I am using a Chimay-style of recipe, but instead of Belgian Candy Sugar, I am using agave syrup (not nectar, I actually got it from a friend's tequila distillery in Mexico and brought it home with me. It's the stuff they make tequila out of, direct from the oven.)

Can anyone help me? I think, based on the readings, my experiment may have produced a beer that is extremely low in alcohol.

before-after.jpg  
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Old 02-09-2013, 11:47 PM   #2
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1.072 and 1.030. I use Rooftopbrew website and enter those numbers in their ABV calculator. You probably haven't reached final gravity yet though as its only fermented a week.

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Old 02-09-2013, 11:47 PM   #3
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Based on a 1.074 OG and a 1.030FG your ABV would be5.8%

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Old 02-09-2013, 11:50 PM   #4
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It's still bubbling in the secondary now, so I wonder how high it is likely to go. Thanks for helping me out - I think I see what you're reading now.

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Old 02-10-2013, 12:02 AM   #5
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You certainly didn't make a weak beer. Your final grav may get down below 1.020. You would have a 7 plus ABV.
Just rough estimates.

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Old 02-10-2013, 12:08 AM   #6
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Quote:
Originally Posted by grovedude View Post
It's still bubbling in the secondary now, so I wonder how high it is likely to go. Thanks for helping me out - I think I see what you're reading now.
It's more of a how low will it go. Not knowing what you are looking for I'm guessing you are wanting a beer to finish around 1.020 which is 7.1%
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Old 02-10-2013, 12:10 AM   #7
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Thanks! I love this forum!!!!

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Old 02-10-2013, 12:13 AM   #8
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A simple rule of thumb is to use this equation:

ABV% = (OG - FG) * 131

So in your case:

ABV% = (1.072 - 1.030) * 131 = 5.5


There are other formulas out there, and calculating the actual ABV can actually get quite complicated if you look into the details, but that approximation works well for most beers.

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Old 02-10-2013, 12:16 AM   #9
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don't bother with math. that's for university dayze...

http://www.brewersfriend.com/abv-calculator/

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Old 02-10-2013, 12:31 AM   #10
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Quote:
Originally Posted by iaefebs View Post
I like how different people read the same scale 3 different ways while everyone read the 1.030 current. I have to ask weirdboy, how did you come up with seeing a 1.068?
Sorry, it was 1.072...I meant to change that number in my other post. I guess I ought to do that so as not to cause more confusion.
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