Kaiser
Well-Known Member
So I'm trying to come up with a way to determine mash and lauter efficiency separately. Not because I have problems, but to provide better means of troubleshooting brewhouse efficiency. I define mash efficiency as the ratio between the extract that was dissolved into the mash and the maximum extract that was available in the grain. Lauter efficiency is the ratio between the extract that made it into the kettle and the extract that was dissolved into the mash. The product of both is the brewhouse efficiency and that is the efficiency that most of us report, brag or complain about and use to size recipes.
The motivation for this stems from the fact that both efficiencies are affected by different parameters are need to be addressed differently. If there are shortcomings in your mash efficiency, you should not make up for them by sparging more as this may lead to oversparging problems. Similar, lauter efficiency problems cannot be compensated for with increasing the mash efficiency if that is already 100%.
To measure the mash efficiency I think that taking a gravity reading of the first wort should give you an idea where you are. If there is 100% mash efficiency, the extract content (=gravity) of the first wort in Plato should be:
FW extract in Plato = (grain weight in kg * 0.8 ) / (grain weight * 0.8 + strike water volume in l)
The 0.8 multiplier for the grain weight is the laboratory extract of that grain. For most base malts its 80% or close. The water volume is the volume of all the water (including water added by batch spargers to equalize run-offs) added before stirring and taking a gravity reading. Your mash efficiency is now the measured extract vs. the calculated extract. It should be close to 100%. This works well for those of you who have a refractometer as you can actually take gravity readings fairly easily.
When I brewed my Helles this weekend, I added 17.5l of water, had 4.0kg of grain and got a FW gravity of 16 Plato. The expected FW gravity was actually 15 Plato, but I contribute this to measurement errors and try to do better next time around as you mash efficiency is unlikely to exceed 100%.
So if your brewhouse efficiency is low, or you are just curious, you may want to give this a try. And if the FW gravity/extract is significantly less than what you expected the following parameter can have something to do with that:
- pH
- crush (though I'm starting to get convinced that this should not have as big of an impact as it is reported)
- mash-out (can access starches that single infusion cannot)
- time
Kai
The motivation for this stems from the fact that both efficiencies are affected by different parameters are need to be addressed differently. If there are shortcomings in your mash efficiency, you should not make up for them by sparging more as this may lead to oversparging problems. Similar, lauter efficiency problems cannot be compensated for with increasing the mash efficiency if that is already 100%.
To measure the mash efficiency I think that taking a gravity reading of the first wort should give you an idea where you are. If there is 100% mash efficiency, the extract content (=gravity) of the first wort in Plato should be:
FW extract in Plato = (grain weight in kg * 0.8 ) / (grain weight * 0.8 + strike water volume in l)
The 0.8 multiplier for the grain weight is the laboratory extract of that grain. For most base malts its 80% or close. The water volume is the volume of all the water (including water added by batch spargers to equalize run-offs) added before stirring and taking a gravity reading. Your mash efficiency is now the measured extract vs. the calculated extract. It should be close to 100%. This works well for those of you who have a refractometer as you can actually take gravity readings fairly easily.
When I brewed my Helles this weekend, I added 17.5l of water, had 4.0kg of grain and got a FW gravity of 16 Plato. The expected FW gravity was actually 15 Plato, but I contribute this to measurement errors and try to do better next time around as you mash efficiency is unlikely to exceed 100%.
So if your brewhouse efficiency is low, or you are just curious, you may want to give this a try. And if the FW gravity/extract is significantly less than what you expected the following parameter can have something to do with that:
- pH
- crush (though I'm starting to get convinced that this should not have as big of an impact as it is reported)
- mash-out (can access starches that single infusion cannot)
- time
Kai