BIAB Efficiency 102.8% <--- How's that possible?

Discussion in 'Brew Sessions' started by time2brew, Sep 28, 2013.

  1. time2brew

    time2brew New Member

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    I'm a BIAB brewer and new to Brewer's Friend. I'm trying to understand the efficiency data-entry and the results I'm seeing.

    Here's a batch I just brewed that produced efficiency numbers which I don't understand.

    Thanks in advance for any guidance anyone can provide!

    Conversion: 102.8% <--- How's that possible?
    Pre-Boil: 87% 31.7 ppg
    Ending Kettle: 91% 33.1 ppg
    Brew House: 67% 24.5 ppg

    Here's the values I plugged in that produced those efficiency results

    Mash Complete:
    Volume: 8.5 gal <--If I use the pre-boil volume I get a conversion of 93.7% which seems more reasonable
    Gravity: 1.045

    Pre-Boil Gravity
    Kettle Volume: 7.75 gal
    Gravity: 1.045

    Boil Complete
    Kettle Volume: 6.75
    Orig Gravity: 1.054

    Fermentation Complete
    Final Gravity: 1.012



    Water Gallons Quarts
    Total mash water needed 8.51 34
    Grain absorption losses -0.74 -3
    Starting boil volume 7.77 31.1
    Boil off losses -1 -4
    Kettle dead space -1 -4
    Hops absorption losses -0.02 -0.1
    Misc. losses -0.25 -1
    Amount going into fermentor 5.5 22
    Total: 8.51 34




    Fermentables
    Amount Fermentable PPG °L Bill %
    10 lb American - Pale 2-Row 37 1.8 90.9%
    0.5 lb Belgian - CaraMunich 33 50 4.5%
    0.5 lb American - Chocolate 29 350 4.5%
    11 lb Total 
     
    Hops
    Amount Variety Type AA Use Time IBU
    0.5 oz Northern Brewer Pellet 7.8 Boil 60 min 14.73


    Mash Guidelines
    Amount Description Type Temp Time
    -- BIAB Temperature 150 F 60 min

    Other Ingredients
    Amount Name Type Use Time
    20 g Pumpkin Pie Spice Spice Boil 5 min
    1 each Whir-floc tablet Fining Boil 15 min

    Yeast
    Fermentis / Safale - English Ale Yeast S-04
    Attenuation (avg):72%
    Flocculation:Medium
    Optimum Temp:59 - 75 °F
    Starter:No
    Fermentation Temp:70 °F
    Pitch Rate:0.35 (M cells / ml / ° P) 99 B cells required
     
  2. LarryBrewer

    LarryBrewer Active Member

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    That all looks pretty good.

    Higher than 100% efficiency just means you mashed slightly more grain than the recipe called for, or the ppgs in the recipe editor were slightly lower than what was actually purchased. Grain ppg does vary slightly year to year. Not all scales are accurately calibrated at LHBSs.

    As for the Pre-Boil: 87% 31.7 ppg vs Ending Kettle: 91% 33.1 ppg, that is just due to rounding errors in measurment, but in theory should be exactly the same, unless the pumpkin spice had some sugars in it?

    93.7% conversion would be low. It is possible there was some stratification which threw off that reading.
     

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