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Figuring attenuation.

Discussion in 'Homebrewing' started by yinzer, Jan 12, 2013.

  1. yinzer

    yinzer Savant (395) Pennsylvania Nov 24, 2006

    While I'm not looking for the mathematical answer - I used a spreadsheet that I downloaded, feel free to check my math. But how do you come to the conclusion that you have good attenuation?

    Yeast WLP007 - Attenuation: 70-80%

    ESB 64.4%
    Dark Munich 9L 12.4%
    DME 5%
    D-9 2.5%
    D-180 2.5%
    Roasted Barley 3.7%
    Crystal 55L 2.7%
    Roasted Wheat 2.5%
    Choc malt 2.5%
    Carafa II 1.9%

    27.4 original
    15.2 current (@ six days)
    76.8 apparent
    11.77 ABV

    mashed 148-150 60 min (I wanted lower)

    On one hand it looks good, but I do have 5% sugar, mashed kinda low'ish and not much crystal. I'm going to let it sit another week @ 74*F.

    So should I be happy?
  2. VikeMan

    VikeMan Champion (930) Pennsylvania Jul 12, 2009 Verified

    What I do is keep notes on attenuation levels I have historically got with a given yeast strain, grain bill, and mash temp. Then, when I brew something with sugar, I calculate expected attenuation based on history for just the non-sugar part of the Original Gravity, and 100% attenuation for the sugar. Similarly, when using something like Lactose or Maltodextrin I assume 0% attenuation for that part of the original gravity.