Efficiency is constantly crazy low.. why?!

There are many different efficiencies defined for the brewing process:
Conversion Efficiency: The actual amount of sugar created in the mash divided by the potential amount of sugar in the grain bill.
Lauter Efficiency: The amount of sugar that makes it into your boil kettle divided by the amount of sugar that was created in the mash.
Mash Efficiency: a.k.a. Pre-Boil Efficiency. The amount of sugar that makes it into your boil kettle divided by the potential amount of sugar in the grain bill. Mash Efficiency equals Conversion Efficiency times Lauter Efficiency.
Transfer Efficiency: The amount of sugar in your fermenter divided by the amount of sugar in your boil kettle. Also equal to the fermenter volume divided by the post-boil volume.
Brewhouse Efficiency: The amount of sugar that makes it into your fermenter divided by the potential amount of sugar in the grain bill. Brewhouse Efficiency equals Mash Efficiency times Transfer Efficiency. Also equals Conversion Efficiency times Lauter Efficiency times Transfer Efficiency.
All of the above definitions are for fractional efficiency. You can convert any fractional efficiency to percentage by multiplying by 100%. However, if you are multiplying efficiencies together, you need to do that with fractional efficiencies.

The first thing to do is determine if your low efficiency is due to low conversion efficiency, poor lauter efficiency, or poor transfer efficiency (if it's your brewhouse efficiency that you think is low.) They are caused by different mechanisms, and require different actions to improve them.

Conversion efficiency can easily be measured just by measuring the SG of the wort in the mash. Turns out the maximum SG of the wort in the mash (at 100% conversion) is almost totally dependent on the mash thickness. Kai Troester provides a table of mash thickness vs. max SG here, and describes how to use that, and your measured SG, to determine conversion efficiency. If your conversion efficiency is less than about 95%, you should try to improve it. Things to do to improve your conversion efficiency:

• Crush finer.
• Mash longer.
• Stir the mash more.
• Make water adjustments to keep mash pH in the range of 5.2 to 5.7.
• Add more diastatic power to the mash.

Mash efficiency can be obtained using on-line calculators using either post-boil volume and post-boil SG measurements, or pre-boil volume and pre-boil SG. It's easier to get accurate SG measurements post-boil, since pre-boil wort can have significant stratification if you sparge, and it's difficult to mix well enough to completely eliminate the stratification. However, you cannot use the post-boil measurements if you added any sugar during the boil. Once you have your mash efficiency, divide by the conversion efficiency to determine your lauter efficiency. Then compare your lauter efficiency to the chart below. A traditional MLT should have a grain absorption rate of about 0.12 gal/lb, so use those curves in your comparison (unless you are BIAB'ing and squeezing the bag.) If you are fly sparging, and your lauter efficiency is less than that for batch sparging, then you are wasting your time by fly sparging. Factors that negatively affect batch sparge lauter efficiency:

• Inadequate stirring. Need to stir well before vorlauf and drain for each run-off.
• Excessive undrainable volume in the MLT. Undrainable volume in the MLT should be minimized, and ideally less than a pint (0.125 gal.)

Factors that negatively affect fly sparge lauter efficiency:

• Channeling. This can be caused by poor false bottom or manifold design, or sparging too fast.
• Sparging too fast, thus not allowing enough time for diffusion to move sugar into the sparge water.

If your conversion and lauter efficiencies are both acceptable, but your brewhouse efficiency is low, then look at your equipment to find and eliminate places that retain wort, and thus keep it from ending up in the fermenter.

Brew on

max384 said:

Nobody's going you drink your beer and tell you it tastes like you have low efficiency.

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Yup totally stealing that.. hilarious!

Hahaha. Thanks guys.... I only wish I hadn't made the autocorrect error!

max384 said:

Hahaha. Thanks guys.... I only wish I hadn't made the autocorrect error!

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Nothing a little quotoshop can't fix [emoji23]

doug293cz said:

There are many different efficiencies defined for the brewing process:
Brew on

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Amazing info, thanks a bunch!!

jojacques said:

Its a good point.
Just to make sure my setup allows for batch sparge: Is it ok if I cannot dump all the sparge water real fast to the mash (so the water stirs the grains)?

I am using a 3 tiers brewstand, so I open my HLT valve and can drop 5 gallons of water in my mash tun in about 1 minute. I would need to stir the mash myself... is this a big deal?

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Just drain your sparge water in, give it a good stir, vorlauf, drain into the kettle.

For mill gap, when I last batch sparged (I now do full volume BIAB) my mill was set at .033 with no stuck sparges. I imagine .035 would get you some improvement with no stuck sparge. Be sure that if using any wheat malt you mill those separately on a tighter setting and add rice hulls to your mash.

Read my blog post on troubleshooting efficiency.

Take more measurements to separate lauter efficiency and conversion efficiency. (details in blog post). Take a look at my mash calculator for an estimate on sparge efficiency, which basically compares your lauter efficiency to that of an ideal batch sparge. If it's not at least 130%, I would recommend not fly sparging.

I have been dealing with very low conversion efficiency as well. I finally called public works, got a water report, and spoke to the guy who runs the treatment plant! Apparently we have total dissolved solids around 212-235 but almost 0 calcium and about 110 of that TDS is dissolved silicate. I know the calcium is a huge factor, but I suspect that silicate has to be having an effect as well. Does anyone know what effect if any silicate has and how to address it?
And what would you use to add calcium and in what amounts?

TANSTAAFB said:

I have been dealing with very low conversion efficiency as well. I finally called public works, got a water report, and spoke to the guy who runs the treatment plant! Apparently we have total dissolved solids around 212-235 but almost 0 calcium and about 110 of that TDS is dissolved silicate. I know the calcium is a huge factor, but I suspect that silicate has to be having an effect as well. Does anyone know what effect if any silicate has and how to address it?
And what would you use to add calcium and in what amounts?

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That sounds like terrible brewing water. Just adding calcium won't get rid of the other crap in it. What else is in there that makes up the other 110 - 120 of TDS? I wouldn't be surprised if it had other bad stuff, like iron for example. If I had water like that, I would just go with straight RO water, and build up the ions to a reasonable profile. You can buy RO water at most grocery stores, or install your own RO water generation system at home.

Brew on

My beer tastes great but I'm sure it would taste even better with good water! I used to brew with really hard but really good Texas well water. Damn... I was hoping to avoid screwing with water and building up from scratch...