Calculation of ABV

Discussion in 'Recipe Editor' started by Karl, Dec 29, 2014.

  1. Karl

    Karl New Member

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    Fermentation have finished in two beers of mine. I entered the measured Brix and SG in the excel data sheet which calculated an estimated ABV of 6.3 based on original Brix of 13.5 and final Brix of 6.9 in one of the beers (ABV 5.3 in the other - see below).
    I entered the same readings in the brew session calculater and got an ABV of 3.54 (see further below).

    Why do these calculations come up so different?

    Excel spreadsheet:
    Refractometer Final Gravity Calculator
    from http://seanterrill.com Version 3.0
    Fields in red are required. Wort correction factor: 0.91
    Fields in green are optional. (default: 1.04)
    Refractometer FG Correlations
    Batch # Name/Description Orig °Brix Final °Brix OG Hydro FG Old Cubic New Cubic New Linear Attenuation App. Atten. ABV
    1 Sierra Nevada 13.5 6.9 1.060 1.0110 1.0111 1.0139 1.0138 66.4% 81.0% 6.3%
    2 Märzen 13.8 8.2 1.062 1.0200 1.0193 1.0190 1.0185 54.5% 66.5% 5.3%

    Brew session:
    Alcohol and Attenuation:
    ABV: 3.54%
    Apparent Attenuation: 49.7%
    Actual FG: 6.9 °P
    Calories per 355mL: 186
    ABV Calculations FAQ ?
     
  2. Austin

    Austin Member

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    We're taking a look Karl.
     
  3. Karl

    Karl New Member

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    I just realised that in the brew session ABV calculator it interprets my Brix measurement as the "real" corrected (for alcohol) one. Hence the Brix 6.9 reading is converted to a final Sp.G of 1.028.
     

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