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Thread: Percent Alcohol calculation

  1. #1
    Join Date
    Oct 2002
    Location
    Sweden
    Posts
    134

    Percent Alcohol calculation

    I calculate (OG-FG)*0,132 to get % alcohol by volyme. This formula is approved by the Swedish Tax. But I have seen breweries calculate with 0,127 and this website has a calculator which use 0,130. Should I revise my calculation?

  2. #2
    Join Date
    Oct 2002
    Location
    India
    Posts
    138
    Calculation of Alcohol streangth

    (OG-PG) x f = %ABV

    "The value of 'f' is not constant because the yeild of alcohol is not constant for all fermentations. In lower streangth beers, more of the sugars available for fermentation are consumed in yeast reproduction than in producing alcohol"

    Some factors produced by the Lab of Goverment chemist(U.K.)

    (OG - PG)..... %ABV ......Factor
    10.5 - 17.2.. 1.3 - 2.1 ... 0.127
    26.2 - 36.0 .. 3.3 - 4.6 ... 0.129
    36.1 - 46.5.. 4.6 - 6.0 ... 0.130
    57.2 - 67.9.. 7.5 - 9.0 ... 0.132

    Recommend you verify your calculation with an analysis of your beer on a regular basis. (e.g., once a year)
    matt
    Last edited by matt; 02-16-2004 at 05:37 PM.

  3. #3
    Join Date
    Dec 2003
    Location
    London, United Kingdom
    Posts
    181
    Hi,

    For ABV, I use:

    (OG-PG) x 0.52945

    with gravity being in Plato. However, where I work we analyse all alcohols by distillation as calculations are always just around-about.

    Cheers!

    Alex

  4. #4
    Join Date
    Mar 2003
    Location
    Baton Rouge, LA
    Posts
    618

    Exclamation Interesting!

    I use the following from "Malting and Brewing Science":
    (Og-Fg)X .516 with gravity measured in *Plato.
    Interesting there is controversy on this. Remember though, that final reading is apparent extract and not real. I was using a rounded .52 but switched. Anyways, for a pub brewer its close enough!

  5. #5
    Join Date
    Oct 2002
    Location
    India
    Posts
    138
    Original response and Factors are for Specific gravity.
    There is approximately 4 degrees Specific gravity for 1 Plato.
    If you convert the plato factors(divide by 4) you have the Specific gravity factors;

    .52945 / 4 = 0.132...

    .516 / 4 = 0.129

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