Am I understanding what efficiency is?

[Senior Monkey]

We're new to brewing (6 all-grain batches so far). We want to make sure we are understanding brewing efficiency.
Our most recent batch was a single hop using 24 lbs of pale 2-row malt. So - is this correct?
Theoretically, we should get 888 gravity points (24 * 37 PPG)?

After mashing and lautering/sparging we got 13 gallons pre-boil at 1.054. That is 702 gravity points. So if we measure efficiency at that time we get 702/888 = 79%.

In the fermenter, we had 10.5 gallons at 1.068. So our brewhouse efficiency would be
(10.5 * 68)/888 = 80%

Are we doing the calculations correctly?

 

[IslandLizard]

Are we doing the calculations correctly?

Yup, beautiful!
A textbook classic...

... except what's a little puzzling is that your BH efficiency is higher than your mash efficiency. At best, they would be the same, 100% transfer, no wort lost or any left behind. It could be due to a small measuring error somewhere. Such as a small deviation in gravity and/or volume.

You could probably increase your mash efficiency somewhat (and BH efficiency too), for example by milling finer.

What is your brewing method? Fly sparging? Batch sparging? BIAB, with or without sparge?

 

[Vale71]

Your volume measurements are probably a bit off. From 13 gallons at 1.054 pre-boil you would only get 10.3 gallons at 1.068 post-boil. Unless you dumped everyithing in the fermenter you should have a bit less than that and certainly not a bit more.

 

[bracconiere]

Unless you dumped everyithing in the fermenter

that's what i always do? (i use hop bags, don't have a spigot on my kettle)

 

[hottpeper13]

Brewhouse efficiency is measured at knockout kettle full and chilled. For me it's 5.5gal in kettle then transfer 5 gal to fermenter, so you measure the 5.5 gal as brewhouse even though all of it is the same gravity.

 

[eric19312]

That small difference could be thermal expansion. Water at near boiling has about 4% greater volume than water at room temp. Mash temp is in between.

 

[Senior Monkey]

Yup, beautiful!
A textbook classic...

... except what's a little puzzling is that your BH efficiency is higher than your mash efficiency. At best, they would be the same, 100% transfer, no wort lost or any left behind. It could be due to a small measuring error somewhere. Such as a small deviation in gravity and/or volume.

You could probably increase your mash efficiency somewhat (and BH efficiency too), for example by milling finer.

What is your brewing method? Fly sparging? Batch sparging? BIAB, with or without sparge?

First, thanks to all who replied. We were also surprised that our Brewhouse efficiency was higher and assumed that it was a measuring error. (Our volume estimating technique is quite crude.) IslandLizard asked about our brewing technique.
During the mash, we continually recirculate the wart as if we were fly sparging and at about the same rate. It seems to make our wart a lot clearer. Then, we fly sparge as we transfer the wort to the boil kettle. These forums are an awesome way to learn. Thanks again.

 

[doug293cz]

Brewhouse efficiency is measured at knockout kettle full and chilled. For me it's 5.5gal in kettle then transfer 5 gal to fermenter, so you measure the 5.5 gal as brewhouse even though all of it is the same gravity.

Although some authors define brewhouse efficiency this way (end of boil eff, aka knockout eff), others define brewhouse efficiency as efficiency into the fermenter. One reason for this is that end of boil efficiency is the same as mash (pre-boil) efficiency, except when you add fermentables to the BK (or you lose a significant volume due to boil over.)

Both BrewersFriend and BeerSmith define brewhouse efficiency based on volume into the fermenter. You should use the definition that agrees with what your brewing software uses if you want to avoid confusion.

Brew on

 

[hottpeper13]

I use brewing calculations , pencil, calculator and an eraser to get my numbers. Don't know about any software. all i know is the brewhouse is before the fermenters and the fermenters are before packaging. Did I mention the eraser?

 

[ScrewyBrewer]

Simply put brewhouse efficiency is the percentage of sugars converted in the mash that remain in the wort when it goes into the fermenter.

 

[doug293cz]

Simply put brewhouse efficiency is the percentage of sugars converted in the mash that remain in the wort when it goes into the fermenter.

Not quite. Brewhouse efficiency (using BF & BS definition) is: percentage of potential sugar (extract more correctly) in the grain bill that makes it into the fermenter.

Brewhouse Efficiency = Conversion Efficiency * Lauter Efficiency * Transfer Efficiency

Conversion Efficiency = Extract Created in the Mash / Potential Extract in the Grain Bill
Lauter Efficiency = Extract in Boil Kettle / Extract Created in the Mash
Transfer Efficiency = Extract in Fermenter / Extract in Boil Kettle​

Brewhouse Efficiency = Extract in Fermenter / Potential Extract in the Grain Bill

I parse your definition as: Lauter Efficiency * Transfer Efficiency. You appear to have left out conversion efficiency.

Brew on