# 100% mash effeciency?

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#### taulpondolo

##### Well-Known Member
Brewed a hefe today and just took the gravity of the samples. Pre boil was 1.052 (its what the post boil shouldve been. Post boil ended up around 1.064. Brew father says its about 100% mash efficiency, is that possible? I typically get around 85 so it seems odd. Especially with a fluid sparge vs stuck like the last couple brews.

5.5 gallon in fermenter

6lb avangard wheat malt
3lb 6oz avangard pilsner malt
4 oz melanoidin weyermann

90 min mash 153

100% mash efficiency is not theoretically possible. Mash efficiency is equal to conversion efficiency times lauter efficiency. It is possible to get 100% conversion efficiency (by definition, that's what happens in a Congress mash), but lauter efficiency is always less than 100%. Lauter efficiency = 100% * (1 - fraction of sugar left in grain bed after lautering.) You cannot get all of the sugar rinsed from the grain without over-sparging. You can get close to 100% lauter efficiency with special equipment (filter press), but these are not common in home brewing.

Efficiency calculations cannot be more accurate than the measurements that go into the calculation. Measurements needed to calculate mash efficiency are:
• Grain bill weight
• Weighted average grain bill potential
• Weighted average grain bill moisture content
• Pre-boil SG
• Pre-boil Volume
• Post-boil SG and Volume can be used instead of pre-boil, but you can't mix pre and post measurements
Given the typical accuracy of the needed measurements as made by homebrewers, it turns out that an efficiency calculation has an uncertainty of +/- 3 - 4 percentage points.

Brew on

100% mash efficiency is not theoretically possible. Mash efficiency is equal to conversion efficiency times lauter efficiency. It is possible to get 100% conversion efficiency (by definition, that's what happens in a Congress mash), but lauter efficiency is always less than 100%. Lauter efficiency = 100% * (1 - fraction of sugar left in grain bed after lautering.) You cannot get all of the sugar rinsed from the grain without over-sparging. You can get close to 100% lauter efficiency with special equipment (filter press), but these are not common in home brewing.

Efficiency calculations cannot be more accurate than the measurements that go into the calculation. Measurements needed to calculate mash efficiency are:
• Grain bill weight
• Weighted average grain bill potential
• Weighted average grain bill moisture content
• Pre-boil SG
• Pre-boil Volume
• Post-boil SG and Volume can be used instead of pre-boil, but you can't mix pre and post measurements
Given the typical accuracy of the needed measurements as made by homebrewers, it turns out that an efficiency calculation has an uncertainty of +/- 3 - 4 percentage points.

Brew on
Exactly what i figure.

Thanks a million

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