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: 13.7 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 →
Result: 70.6%

Method2: GrainFather Calculator → Calculators
Result: 74%

Method3: Brew Friends Calculator
Result: 66.86%

Method4: BrewFather
Result: 61.84%

Equipment Profile: GrainFather G30
PH: 5.7
Boil Vol: 13.7
Pre-Boil Gravity: 1.044
Post-Boil Volume: 9,5
Post-Boil Gravity: 1.0637

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

 

[moto748]

My attitude would be, it's an art, not a science. All these clever calcs at the end of the day rely on some assumptions which may or may not fully apply to your ingredients and indeed your method.

I would have thought the best thing would be to stick to one formula, and then you will have a better handle on comparing efficiencies from brew to brew. Even of the 'actual' values are not spot-on.

End of the day, as long as long as your beer tastes good, does it really matter?

 

[Jim Brewster]

Just to point out that one of your values is 13.07L instead of 13.7L but it doesnt look like it was used in the calculation anyway, or was it?

 

[kharand]

Just to point out that one of your values is 13.07L instead of 13.7L but it doesnt look like it was used in the calculation anyway, or was it?

Good catch! You are right. It should be 13.7 liters instead 13.07.

 

[Hazelwood Brewery]

I use a similar approach to your method 1 and my results match.

Looking at the calculator for Grainfather (method 2), there is nowhere to record the grains and weights you used so the calculator appears to be using 35 points per pound per gallon as it’s default. The actual extract potential for your grain is 36 points per pound per gallon.

The other calculators will either be doing something similar to Grainfather or will be using a table of max extract potential that is slightly more/less accurate than the one you and I are using for method 1.

 

[kharand]

@Hazelwood Brewery thanks for the answer :-)

I finally was able to get similar results in the 5 methods I used. The problem was that I need it to select Batch Volume Target = Kettle in BrewFather app. Otherwise Trub/Chiller loss was take into consideration, while in the other methods was not.

Finally I got this close efficiency (pre-boil) results in all 5 methods:

 

[Hazelwood Brewery]

@Hazelwood Brewery thanks for the answer :-)

I finally was able to get similar results in the 5 methods I used. The problem was that I need it to select Batch Volume Target = Kettle in BrewFather app. Otherwise Trub/Chiller loss was take into consideration, while in the other methods was not.

Finally I got this close efficiency (pre-boil) results in all 5 methods:

View attachment 44294

Looks better!