Mashing Efficiency. Am I missing anything?

Discussion in 'Beginners Brewing Forum' started by kharand, Mar 28, 2021.

  1. kharand

    kharand New Member

    Mar 28, 2021
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    Hi folks,

    I’ve done a few batches with GrainFater (G30) already and I’m looking for a reliable way to measure the mash efficiency (or preboil efficiency). I found different ways and they more or less show similar numbers, but still not close enough to make me feel I’m doing it right.

    This is the recipe I did few days ago: West Coast (OG: 1.060 FG: 1.011 ABS: 6%) Swedish: Instruktioner för Stigbergets West Coast 20-liter - Det Lilla Köksbryggeriet

    Note: I adapted the recipe to 50% of the batch, so, instead of 20 liters I was targeting 10 liters (to fermenter)

    Adapted Recipe (reducing 50% of the grain):
    • Weyermans Pale Ale (2.5kg, DBFG or Extract fine D.M: 79%)
    • Crisp Cara Gold (0.15kg, DBFG or Extract fine D.M: 74%)
    • Crisp Terrefied Wheat (0.15kg, DBFG or Extract fine D.M: 82%)

    Mashing Results (following GrainFather calculator):
    • Mash Water: 11.06 liters
    • Sparging Water: 6.18 liters
    • Result: 13.7 liters Gravity: 1.044

    Method1: Gravity - Hillybeer

    ExtraPotentialPaleAle → 305.33
    ExtraPotentialCaraGold → 286.01
    ExtraPotentialTorrefiedWheat → 316.93
    WeightedExtraPotential → 304.92
    SGP = 44 (1.044)
    Volume: 13.07 liters
    Weight: 2.8 (2.5+0.15+0.15)

    EE = (SGP x V) / (W x EP) → (44*13.7) / (2.8*304.92) → 0.706 → 70.6%

    : GrainFather Calculator → Calculators
    Result: 74%

    : Brew Friends Calculator
    Result: 66.86%

    Method4: BrewFather
    Result: 61.84%


    Any idea why such different results (specially the one coming from BrewFather)? Which way do you normally use to measure mash efficiency?
  2. Hawkbox

    Hawkbox Well-Known Member

    Jul 27, 2017
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    IT Manager
    Honestly I personally just record the numbers and see if it's anywhere near the expected preboil gravity. It seems like they are using considerably different formulas to calculate that number.

    What I find in my personal experience is that 5kg of grain will make a 5G (21 liters) batch of beer with an OG of 1.050 at 70% efficiency.

    They're all just calculations so there will be variance, but if you're worried about getting it dialed in I would suggest using the numbers I mentioned above with your grainfather and see where you end up.
  3. Craigerrr

    Craigerrr Well-Known Member

    Mar 14, 2018
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    The best thing is to pick one of the software options and run with it.
    Make adjustments to your efficiency until you are hitting your numbers.
    Note that efficiency will be different for different beers.
    Big beers, and beers with a lot of flaked will yield lower efficiencies.
  4. J A

    J A Well-Known Member

    Jan 19, 2016
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    Austin, Texas
    There's only one metric I pay attention to when measuring mash efficiency - post boil volume and specific gravity. That allows you to calculate the total amount of sugar you got from the beginning of the process. By back-tracking and accurately accounting for losses you can figure out everything you need to know - an accurate pre-boil volume allows you to calculate the pre-boil gravity (same total sugars, more liquid) and by comparing the total mash liquor to the pre-boil volume, you can calculate mash efficiency (same gravity as pre-boil but higher volume).
    I have my system dialed in so that I can estimate mash efficiency accurately based on recipe type (dark beers lower, lighter, all malt beers in the middle and adjunct beers usually higher) but there's still a range of variance of a few points when brewing the same recipe over and over.

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