# Accuracy of efficiency calculators? Different kinds of efficiency?

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#### snarf7

##### Well-Known Member
Brewer's friend has a handy little tool for calculating efficiency based on your fermentables, gravity reading and wort volume:

https://www.brewersfriend.com/brewhouse-efficiency/

They also have a hydrometer/temp calculator so you can your actual gravity even if the wort is still hot: https://www.brewersfriend.com/hydrometer-temp/

As you can see they list 4 options for their efficiency calculations:

• Conversion Efficiency - The percentage of total available sugars that were extracted from the grains inside the mash tun.
• Pre-Boil Efficiency - The percentage of total available sugars that made it into the kettle.
• Ending Kettle Efficiency - The percentage of total available sugars that made it to the end of the boil, before draining the kettle.
• Brew House Efficiency - An all inclusive measure of efficiency, which counts all losses to the fermentor.
Are these all equally accurate calculations or are some better than others? Do you favor one over the other in your brewing? It just seems to me that the Pre-Boil is the most useful because if you screwed something up you can adjust. Like for example your gravity is way too low because you confused kg with lbs in your recipe and you didn't add nearly enough grain...at least at that point you could add some DME and at least wind up with something salvageable.

You really have to parse the different meanings when talking about Efficiency.

Conversion and Pre-Boil (Mash) efficiency describe extract efficiency. They are the only ones out of the four that do.

Pre-Boil (Mash) Efficiency is the only time where a loss in volume can negatively impact extract, i.e. if you don’t get all extract in solution. That’s the Lauter Efficiency component.

IMHO, you have to separate those two from the others.

Kettle Efficiency impacts extract but only through evaporation so it should NOT be used to estimate your extract.

Brewhouse Efficiency is a pure measure of volume Efficiency. Losses post-boil have ZERO affect on extract. This is why it’s so egregious to estimate extract from Brewhouse Efficiency.

Sorry for the rant. I’ve been trying to find a good place to say all this for a while.

You really have to parse the different meanings when talking about Efficiency.

Conversion and Pre-Boil (Mash) efficiency describe extract efficiency. They are the only ones out of the four that do.

Pre-Boil (Mash) Efficiency is the only time where a loss in volume can negatively impact extract, i.e. if you don’t get all extract in solution. That’s the Lauter Efficiency component.

IMHO, you have to separate those two from the others.

Kettle Efficiency impacts extract but only through evaporation so it should NOT be used to estimate your extract.

Brewhouse Efficiency is a pure measure of volume Efficiency. Losses post-boil have ZERO affect on extract. This is why it’s so egregious to estimate extract from Brewhouse Efficiency.

Sorry for the rant. I’ve been trying to find a good place to say all this for a while.

OK, I can definitely appreciate the differences, but in terms of what I care about, aren't the first two the real key? If you don't get adequate efficiency during your mash then everything else is out of whack

OK, I can definitely appreciate the differences, but in terms of what I care about, aren't the first two the real key? If you don't get adequate efficiency during your mash then everything else is out of whack

Right, in terms of extract content, Conversion and Lauter η are king.

Right, in terms of extract content, Conversion and Lauter η are king.

Well in that case I can see why its a pet peeve for you, that term 'brewhouse efficiency' gets tossed around loosely all the time

Well in that case I can see why its a pet peeve for you, that term 'brewhouse efficiency' gets tossed around loosely all the time

I’m just of the opinion it’s bad to use it to estimate extract of a batch.

OK, I can definitely appreciate the differences, but in terms of what I care about, aren't the first two the real key? If you don't get adequate efficiency during your mash then everything else is out of whack

On the other hand, if you leave 1 gallon of wort behind in your pumps, hoses, plate chiller, etc. things can get out of whack on that end too. In then end, the combined efficiency numbers help you determine "how much water and grain do I need to mix to get 5 gallons of 1.060 OG beer into my keg". Measuring at each step gives some insight into what drives your efficiency numbers and where you lose wort. Some people are more concerned about the "5 gallons" number and some are more concerned about the "1.060" number...ideally you would hit them both. Repeatability and predictability are more important that having high or low numbers.

P.S. I recently brewed some hoppy NEIPA-style beers. It made me realize that, if I am targeting a certain amount of volume into a keg, I need to do a better job of accounting for the amount of volume that hops suck up.

P.S.S. For many years I brewed all-grain an only took an OG reading when transferring into my fermenter and estimated the amount into the fermenter/keg. I plugged 75% into the software I was using and (as long as my sparge went okay) I was close to my target OG and volume.

On the other hand, if you leave 1 gallon of wort behind in your pumps, hoses, plate chiller, etc. things can get out of whack on that end too.

The problem with that logic is that extract only changes when Mashing (grain to wort) and boiling (evaporation).

If I have 5 gallons post-boil wort at 1.060 and I lose 1 gallon going into the fermenter, I still have 4 gallons of 1.060 wort. Losses post-boil don’t affect gravity.

If I have 5 gallons post-boil wort at 1.060 and I lose 1 gallon going into the fermenter, I still have 4 gallons of 1.060 wort. Losses post-boil don’t affect gravity.

4 gal of 1.060 wort <> 5 gal of 1.060 wort

There is no reason to worry much about your mash efficiency if you are going to basically dump a gallon of your beer on the ground. Both sides of efficiency matter to most of us...or at least it matters to me.

4 gal of 1.060 wort <> 5 gal of 1.060 wort

There is no reason to worry much about your mash efficiency if you are going to basically dump a gallon of your beer on the ground. Both sides of efficiency matter to most of us...or at least it matters to me.

Right. I don’t disagree. All I’m pointing out is that Brewhouse Efficiency isn’t an extract based metric.

I worry about my mash efficiency because it sets my potential extract. If I want to ensure trub free wort into the fermenter, I know that I can leave enough volume behind without affecting my gravity. I picked the number I did above arbitrarily to prove a point.

Obviously most people arent leaving 20% of thier post boil wort behind.