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So, who is good with math?

Discussion in 'General Homebrew Discussion' started by Beer_Eugenics, Apr 29, 2012.

 

  1. #1
    Beer_Eugenics

    Well-Known Member

    Posted Apr 29, 2012
    If I add 375ml of 180 proof whiskey to a 5 gallon batch how much would this raise my ABV. I came up with about 1.8%, sound right?
     
  2. #2
    Bradzukie

    Well-Known Member

    Posted Apr 29, 2012
    I suck at math. Sorry! Curious what your trying to do though.
     
  3. #3
    Beer_Eugenics

    Well-Known Member

    Posted Apr 29, 2012
    AHS Oaked Imperial Whiskey Stout
     
  4. #4
    Bradzukie

    Well-Known Member

    Posted Apr 29, 2012
    Ok. Sounds like something I would try.
     
  5. #5
    RiverCityBrewer

    Well-Known Member

    Posted Apr 29, 2012
    Yeah I get 1.75%
     
  6. #6
    boscobeans

    Well-Known Member

    Posted Apr 29, 2012
    180 proof = 90%

    90% of 375ml=337.5ml

    5gallons=18.93 liters=18930ml

    337.5 / 18930 = .0178 or 1.78%

    bosco
     
  7. #7
    laddg

    Member

    Posted Apr 29, 2012
    We need to know the alcohol content of your beer before we can give you an accurate answer. The answers above are based on adding the alcohol to water, and fail to take into account any alcohol that may already be in the beer.

    The differences are probably pretty minor, but to illustrate - if you were to pour the whiskey into a beer that was already 99% alcohol, you would actually be lowering the alcohol content of your mix. A silly example, but it proves the point.

    So, if you want an accurate answer, we need to know the aldohol content of your beer before the addition. It probably won't make a 1/10% difference from what has already been submitted, but it is required to do the math correctly.

    DJG
     
  8. #8
    blakelyc

    Well-Known Member  

    Posted Apr 29, 2012
    The calc above doesn't take into account the increase in total volume:

    whiskey bump = 337.5 / (18930 + 375) =0.01745 or 1.745%

    Teeny difference :) Assuming that the beer is lower, the current abv isn't necessary to calculate the bump, but would of course be necessary to calculate the final abv.
     
  9. #9
    jeffjm

    Well-Known Member

    Posted Apr 29, 2012
    Not to digress, but what exactly is 180-proof whiskey and how is it different than everclear? :mug:
     
  10. #10
    boscobeans

    Well-Known Member

    Posted Apr 29, 2012
    Forgot about that..:eek:

    bosco
     
  11. #11
    laddg

    Member

    Posted Apr 29, 2012
    I must, respectfully, disagree.

    Without knowing the original alcohol content it is not possible to accurately calculate either the 'bump' in percentage alcohol, or the ABV. Again, the differences are minor, but real.

    If the beer starts off with 0% alcohol, then the calculations above apply well. If the beer started off with 90% ABV (the same as the whiskey), then there would be no effective change, and the bump would be zero, and the final ABV unchanged. As before, if the beer started off with very high alcohol, then the bump would be negative and the final ABV would be lower than original.

    You must know current content to calculate either bump or final.

    DJG
     
  12. #12
    Raenon

    Well-Known Member

    Posted Apr 29, 2012
    Not fully correct, but you're on the right path.

    Whiskey is a distilled spirit, therefore always higher in alcohol than simple beer, which must always be limited by its fermentation. Also, he claimed the whiskey to be 180 proof, which is many times the upper limit of even the most alcohol tolerant yeast.
    The calculations above can give you the volume of alcohol within the whiskey, and you divide that by the sum of whiskey and beer volumes to uncover percentage by volume of the final product that the whiskey will supply.

    Now you just need to divide the percentage of alcohol provided by the beer by the new sum volume.

    18390 ml / (18390+375) = 0.980015897

    So the beer ABV will suffer a 2% loss
    ie: 5% starting ABV reduced to 4.9%, plus the 1.745% calculated earlier, making a final ABV of 6.645%
    (Note: only an example- I do not know the original ABV either, but the math will work with any value)
     
  13. #13
    Raenon

    Well-Known Member

    Posted Apr 29, 2012
    Also, you are you sure about the 180 proof in the whiskey? 90% alcohol is uncommon, at least among commercial varieties...
    If it was a major brand, 80-90 proof, or 40-45% ABV is much more common.
     
  14. #14
    itsme6582

    Well-Known Member

    Posted Apr 30, 2012
    I thought everyone here was an engineer. You sound like a scientist.

    I say it's close enough.
     
  15. #15
    Raenon

    Well-Known Member

    Posted Apr 30, 2012
    Technically, I just run an online shop.
    But since we cater to the e-cig world, specifically the DIY market (which could as easily be referred to as homebrew), I have to be good with weighted ratios. Nicotine By Volume is expected to be a bit more precise than ABV. :p
     
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