Mashing Efficiency. Am I missing something?

[kharand]

Hi,

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%

Method2: GrainFather Calculator → Calculators
Result: 74%

Method3: 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?