# Mash efficiency and brewhouse efficiency

### Help Support Homebrew Talk:

#### cmck2000

##### Member
Hi guys,

I'm doing calculations to determine mash efficiency and brewhouse efficiency and im not sure what Wort volume values i use.
The sample calculations are PLK = Wort Volume x Specific Gravity / Malt kg (All divided by malt PLK)
and Wort Volume x Original gravity = Gravity units (L°)
What
do i use as the wort volume? Is it the total volume pre boil (Initial water and sparge water) or Post-boil before going into the fermenter?

Thanks

#### Holden Caulfield

##### Well-Known Member
While not looking through your formula. For mash efficiency, the goal is to capture the volume that you will be able to calculate the wort points (sugar content) collected versus the maximum possible wort points that can be extracted. That said, it should be your preboil volume (the wort volume collected after lautering).

If you multiply the preboil volume times the (gravity of the preboil volume - 1) *1000 you get the points.

Brewhouse efficiency also accounts for wort point losses downstream of the lautering like kettle loss.

OP
C

#### cmck2000

##### Member
Thats great ! So what you are saying is mash efficiency is preboil volume including sparge water used, and brewhouse efficiency is post boil volume before fermentation?

OP
C

#### cmck2000

##### Member
While not looking through your formula. For mash efficiency, the goal is to capture the volume that you will be able to calculate the wort points (sugar content) collected versus the maximum possible wort points that can be extracted. That said, it should be your preboil volume (the wort volume collected after lautering).

If you multiply the preboil volume times the (gravity of the preboil volume - 1) *1000 you get the points.

Brewhouse efficiency also accounts for wort point losses downstream of the lautering like kettle loss.

Thats great ! So what you are saying is mash efficiency is preboil volume including sparge water used, and brewhouse efficiency is post boil volume before fermentation?

#### Gnomebrewer

##### Well-Known Member
Thats great ! So what you are saying is mash efficiency is preboil volume including sparge water used, and brewhouse efficiency is post boil volume before fermentation?
Preboil volume x gravity should be the same as post-boil volume times gravity.
Sugars aren't gained or lost during the boil. Water is boiled off, leaving less volume at a higher gravity.
eg. preboil might be 10 gallons at 1.040 (400 points). Post boil might be 8 gallons at 1.050 (also 400 points).

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
Hi guys,

I'm doing calculations to determine mash efficiency and brewhouse efficiency and im not sure what Wort volume values i use.
The sample calculations are PLK = Wort Volume x Specific Gravity / Malt kg (All divided by malt PLK)
and Wort Volume x Original gravity = Gravity units (L°)
What
do i use as the wort volume? Is it the total volume pre boil (Initial water and sparge water) or Post-boil before going into the fermenter?

Thanks
You cannot use total brewing water volume (strike water + sparge water) to calculate mash efficiency, because of the volume lost due to absorption by the spent grain. You can use either pre-boil volume in the BK and pre-boil SG, or post-boil volume in the BK (not fermenter) and post-boil SG (aka OG.) As noted by @Gnomebrewer , these should give the same result, unless you added fermentables to the BK that didn't come from the mash, you lost volume due to spills or boil-over (but not evaporation), or you have measurement errors.

I'm not familiar with the units "PLK" and doing gravity points based calculations in the metric system. Using grain potentials in SG form (e.g. 1.037) doesn't work with litres and kilograms. Do you have a link to a reference for using gravity points in the metric system?

Brew on

#### marc1

##### Supporting Member
HBT Supporter
Doug covered mash efficiency. Brewhouse efficiency is based off of the volume and gravity that you get in the fermenter. It takes into account all of the losses for kettle trub, wort in hoses and chillers, etc.

#### mabrungard

##### Well-Known Member
Mash efficiency is a function of the mash's water to grist ratio. The Braukaiser website has a conservative estimate of the peak specific gravity you should see for various water/grist ratios. In my experience, that website's SG estimates have me reaching slightly over 100% efficiency. Of course, its due to those conservative SG values that are given. But they are helpful and if you don't reach that peak SG when you mash at whatever water/grist ratio, then you'll know you've left some potential extract in the tun.

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
Mash efficiency is a function of the mash's water to grist ratio. The Braukaiser website has a conservative estimate of the peak specific gravity you should see for various water/grist ratios. In my experience, that website's SG estimates have me reaching slightly over 100% efficiency. Of course, its due to those conservative SG values that are given. But they are helpful and if you don't reach that peak SG when you mash at whatever water/grist ratio, then you'll know you've left some potential extract in the tun.
I'm curious why you think the max SG vs. mash thickness calculations by Braukaiser are conservative? The formulas used for calculation are:

Max Extract Weight = Weighted Ave % Extract Potential [FGDB] * (1 - Weighted Ave % Moisture) * Total Grain Bill Weight​
Max Wort °P = 100°P * Max Extract Weight / (Max Extract Weight + Strike Water Weight)​
I don't see anything conservative in those formulas.

Braukaiser assumes water has a density of 1.0000 Kg/L. I have duplicated Braukaiser's calculations, but using the actual density of water @ 68°F (20°C) - 8.3304 lb/gal or 0.9982 Kg/L. The difference between my results and Braukaiser's are within rounding error when results are rounded to 0.1°P.

Brew on

#### mabrungard

##### Well-Known Member
I'm curious why you think the max SG vs. mash thickness calculations by Braukaiser are conservative?
I feel they're conservative because I can routinely reach slightly greater than 100% efficiency with my RIMS. There is nothing wrong with what Braukaiser posted. It still produces an acceptable target to achieve.

#### HazyBeer

##### Active Member
Every thing you need to know about mash efficiency is in Palmers Book. "But, when it comes to the efficiency of the mash and lauter, we want to think in terms of the pre-boil gravity." First calculate your points per pound per gallon (PPM) using (X x YY)/Z where X is gallons of wort collected pre boil, YY is gravity points (eg 1.0YY) and Z is pounds of grain. Then use the grain bill and max PPM for each grain to calculate the max PPMs you could have got. Then divide your result PPM's with the max PPM to get your percent efficiency.

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
I feel they're conservative because I can routinely reach slightly greater than 100% efficiency with my RIMS. There is nothing wrong with what Braukaiser posted. It still produces an acceptable target to achieve.
What you are claiming is that you can create more extract in your system than is created in a Congress mash. Do you really believe this is true? If so do you have a hypothesis as to why? Usually when someone claims more than 100% efficiency it's due to measurement and or math errors.

Brew on

#### Gnomebrewer

##### Well-Known Member
Every thing you need to know about mash efficiency is in Palmers Book.
Palmer gives a basic introduction. Braukaiser is far more informative. Palmer doesn't even cover mash conversion efficiency, which, if measured by more brewers, would prevent a whole lot of the 'why is my efficiency so low' threads.

#### HazyBeer

##### Active Member
Palmer gives a basic introduction. Braukaiser is far more informative. Palmer doesn't even cover mash conversion efficiency, which, if measured by more brewers, would prevent a whole lot of the 'why is my efficiency so low' threads.

#### HazyBeer

##### Active Member
I feel they're conservative because I can routinely reach slightly greater than 100% efficiency with my RIMS. There is nothing wrong with what Braukaiser posted. It still produces an acceptable target to achieve.
Please share your grain bill, volume of wort pre-boil and OG of an over 100% batch. While not impossible it is highly unlikely that you got over 100% mash efficiency.

#### mabrungard

##### Well-Known Member
You folks seem to think that a Congress mash extracts ALL the potential from a grist. Additionally, you seem to imply that the PPG values that are posted on Braukaiser represent the maximum possible extract. I don't believe you're correct on either count. Those reported values are limited by the limitations of time and the methodologies. Those interested in this subject can review a resource such as this.

All I'm saying in my previous response, is that the extract values quoted at the Braukaiser site are slightly conservative (low).

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
You folks seem to think that a Congress mash extracts ALL the potential from a grist. Additionally, you seem to imply that the PPG values that are posted on Braukaiser represent the maximum possible extract. I don't believe you're correct on either count. Those reported values are limited by the limitations of time and the methodologies. Those interested in this subject can review a resource such as this.

All I'm saying in my previous response, is that the extract values quoted at the Braukaiser site are slightly conservative (low).
Braukaiser's table assumes a FGDB extract potential of 80%, which corresponds to 1.037 when expressed as an SG, and 4% moisture content. These are reasonable estimates for most typical grain bills, and it makes sense to use these if you don't have better data for your specific ingredients. If you have grains with higher potential, and/of lower moisture content, then Braukaiser's table values will be a little low (meaning you could get an apparent conversion efficiency greater than 100% if you used his values.) It's not difficult to put together a spreadsheet that allows you to calculate a more accurate max mash SG if you have more accurate grain data.

Brew on

#### Gnomebrewer

##### Well-Known Member
No, it was mash lauter efficiency. Mash conversion efficiency is measured in the mash tun, before sparging. It's a bit harder to calculate (I use the calculator (excel spreadsheet) linked from the Braukaiser page above). Mash conversion efficiency measures how well the convertibles have been extracted from grains and converted to sugar. You should achieve at least 90%, preferably 95% to 100% efficiency before beginning your sparge, which is when the mash is finished. The time taken to achieve this will depend on the grain crush (if there are uncracked grains, you might never get there; a very fine BIAB crush might take 30 minutes), mash temp, mash pH etc. with a failure to achieve the above targets indicating a mash problem, rather than lauter problem. Mash lauter efficiency (as per Palmer) is the amount of sugars into the boil kettle, which is commonly measured, but a low efficiency here could be a result of mash issues OR lauter/sparge issues, it doesn't isolate the problem.

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
The Palmer link talks only about post mash, aka pre-boil/post-boil efficiency. It does not touch on conversion efficiency at all.

Conversion efficiency is the % of the maximum possible extract (sugar) available in the grain bill that actually gets created in the mash. In over simplified terms: the percent of the total starch converted to sugars and dextrins.

Lauter efficiency is the % of the actual extract (sugar) created in the mash that gets transferred to the boil kettle. Lauter efficiency is always less than 100% because you cannot get all of the wort separated from the spent grain.

Mash efficiency (or pre-boil efficiency in Brewer's Friend) is equal to conversion efficiency times lauter efficiency.

Conversion efficiency measures how good your mashing process is at creating extract (sugar). Lauter efficiency measures how good your process is at separating wort (and thus extract) from the spent grain. Mash/pre-boil efficiency measures the combined effect of both.

Braukaiser discusses conversion efficiency here. Unfortunately, he uses the term "Brewhouse efficiency" where the rest of the homebrew community uses mash efficiency or pre-boil efficiency.

Brew on

#### HazyBeer

##### Active Member
The Palmer link talks only about post mash, aka pre-boil/post-boil efficiency. It does not touch on conversion efficiency at all.

Conversion efficiency is the % of the maximum possible extract (sugar) available in the grain bill that actually gets created in the mash. In over simplified terms: the percent of the total starch converted to sugars and dextrins.

Lauter efficiency is the % of the actual extract (sugar) created in the mash that gets transferred to the boil kettle. Lauter efficiency is always less than 100% because you cannot get all of the wort separated from the spent grain.

Mash efficiency (or pre-boil efficiency in Brewer's Friend) is equal to conversion efficiency times lauter efficiency.

Conversion efficiency measures how good your mashing process is at creating extract (sugar). Lauter efficiency measures how good your process is at separating wort (and thus extract) from the spent grain. Mash/pre-boil efficiency measures the combined effect of both.

Braukaiser discusses conversion efficiency here. Unfortunately, he uses the term "Brewhouse efficiency" where the rest of the homebrew community uses mash efficiency or pre-boil efficiency.

Brew on
Ok then what formula would you use to calculate Conversion efficiency?

#### Holden Caulfield

##### Well-Known Member
Ok then what formula would you use to calculate Conversion efficiency?
Over the past 3 years of reading thousands of posts, I have never seen a thread that even mentions conversion efficiency. I think it is just assumed to be 100% as anything less implies your mash did not convert all the starches which should not happen unless something serious goes wrong during the crushing/mashing process (poor temp control, too short, not enough diastatic power, very bad crush, etc). Also, it would be impossible to calculate as it would be impossible for a homebrewer to determine if the poor mash efficiency is due to poor conversion or poor lautering. Basically, nobody really bothers with conversion efficiency as it is just assumed to be 100% or if not something went very wrong in the mash.

Your questions suggests that a clarification of the "why" mash efficiency and "brewhouse efficiency" matter and how the basis of how they are derived would help you with the formulas, which are actually quite simple if the higher level concepts are clearly understood.

You should always achieve 100% conversion of your mash, otherwise you will end up with unfermentable starches in your beer. In other words, practice good mashing and grain bill practices and you will hit 100% conversion every time. Don't bother worrying about calculating it.

Brewers capture mash efficiency (or lautering efficiency mentioned above) because it tells them how much of the potential available sugar locked in the kernel was extracted during the mash and ended up in their kettle. This is especially important for commercial brewers as malt is a significant portion of the cost of making beer. In other words, poor efficiency means they are pouring money down the drain - literally. From a home brewer perspective, as long as you hit your target mash efficiency and extracted the sugar you need to hit your target OG, then having a low mash efficiency only means you spent a couple more dollars on grain. Many home brewers are proud of their mash efficiencies often sharing that they got a very high number, but in reality it is not very relevant as long as it is reasonable (say 70 - 80%). What is relevant is that you understand your systems mash efficiency so you can calculate how much grain you need to hit your starting gravity every time.

Brewhouse efficiency is just like mash efficiency except it takes into consideration further sugar losses downstream of the kettle and up to the fermenter, like the wort and trub left in the kettle after racking to the fermenter, which is where realized OG or starting gravity is captured. Just like mash efficiency, commercial brewers care deeply about this as any sugars that do not make it into the fermenter is just money down the drain. The impact of lower brewhouse efficiency on a home brewer is just a few more bucks per batch and it is up to the brewer to decide if the few dollars matter.

So the formula to calculate either mash efficiency or brewhouse efficiency is really just a matter of calculating the max available sugar points locked in your grain bill and the sugar points that made it into your kettle (last two digits of preboil specific gravity * volume) or fermenter (last two digits of OG * volume). Then just divide the realized points from the max available points.

Brewing software packages have databases of max available sugar points for each grain. You can also find the numbers on the internet. There is a lot that goes into the calculation of max points per pound per gallon, like dry basis vs as-is, coarse vs fine grind, which you can dig into if you are interested, but just knowing a published number should suffice for the calculations you seek.

Finally, conceptually brewers are consistent on the usage of mash and brewhouse efficiency. However, the max points calculation may not be consistent across brewers as how grind, dry vs as-is basis and other factors used in the calculation are sometimes applied differently, so just stick with a consistent set of max available points and then determine your systems mash efficiency so that you can apply it against max available points and hit your target OG every time.

#### VikeMan

##### It ain't all burritos and strippers, my friend.
Also, it would be impossible to calculate as it would be impossible for a homebrewer to determine if the poor mash efficiency is due to poor conversion or poor lautering. Basically, nobody really bothers with conversion efficiency as it is just assumed to be 100% or if not something went very wrong in the mash.
I agree that hardly anyone computes conversion efficiency, but it can be done, using the strike water volume, the grain weights and extract potentials, and the gravity at the end of the mash (i.e. before sparging/lautering). And if you know Conversion efficiency and Mash efficiency, you can compute Lauter Efficiency from them. I'd be surprised if @doug293cz hasn't posted the whole suite of formulae somewhere in the forum.

#### Gnomebrewer

##### Well-Known Member
Over the past 3 years of reading thousands of posts, I have never seen a thread that even mentions conversion efficiency. I think it is just assumed to be 100% as anything less implies your mash did not convert all the starches which should not happen unless something serious goes wrong during the crushing/mashing process (poor temp control, too short, not enough diastatic power, very bad crush, etc). Also, it would be impossible to calculate as it would be impossible for a homebrewer to determine if the poor mash efficiency is due to poor conversion or poor lautering. Basically, nobody really bothers with conversion efficiency as it is just assumed to be 100% or if not something went very wrong in the mash.
........
You should always achieve 100% conversion of your mash, otherwise you will end up with unfermentable starches in your beer. In other words, practice good mashing and grain bill practices and you will hit 100% conversion every time. Don't bother worrying about calculating it.
You are partially correct, that if everything is dialled in for the mash you'll achieve close to 100% efficiency. But many brewers (new brewers especially, but also some seasoned veterans) don't have things dialled in. If you measure efficiency into the boil kettle, and it's low, and you haven't measured mash conversion efficiency, how do you know where the problem was? Was it conversion, or a poor lauter? You're flying blind. And it is most DEFINITELY NOT impossible to calculate. It's quite simple (see below). Once you understand your own system, you'll ignore recipes that say 'mash for xxx minutes at yy temperature' because you'll know that only applies to one persons system, you can adapt it to suit your own. FWIW, I have three systems (all home built) that I might use on any brew day - a BIAB, a cooler mash tun and a recirculating RIMS. They all take at least 75 minutes to achieve close to 100% conversion (and then only if I have a rest somewhere up around the 70C/158F range) because of my crush - my grain mill won't crush any finer (grains don't pull through if I close the gap any further). I could buy a new mill, or (as I do) I can just accept that my mash takes a bit longer. If I blindly followed most recipes that say mash for 60 minutes, I'd have unconverted starches left in the grains. Note that this isn't directly because of conversion, it's probably because starches haven't been extracted out of the centre of the grains for conversion to occur, so I probably wouldn't get starch haze, conversion happens fairly quickly once starches are extracted. Someone with a BIAB system crushing very finely can probably get away with a 30 minute or shorter mash - extraction is exponentially faster with smaller grains.

Ok then what formula would you use to calculate Conversion efficiency?
The calculations are given here

But it's much easier just to use Braukaiser's spreadsheet/calculator

I can't get the spreadsheet to open at the moment. If you want it and you can't open it, let me know and I'll send you a copy.

#### Holden Caulfield

##### Well-Known Member
I agree that hardly anyone computes conversion efficiency, but it can be done, using the strike water volume, the grain weights and extract potentials, and the gravity at the end of the mash (i.e. before sparging/lautering). And if you know Conversion efficiency and Mash efficiency, you can compute Lauter Efficiency from them. I'd be surprised if @doug293cz hasn't posted the whole suite of formulae somewhere in the forum.
Understand. Just never saw it brought up in any thread before and I have read a lot of threads . I would guess that most just do an iodine test or nothing (like me) and move on to lautering.

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
Ok then what formula would you use to calculate Conversion efficiency?
Here's how you calculate conversion efficiency (the equations you actually need to use are in bold blue.)

Conversion efficiency is defined as:
Conversion Efficiency = Wt of Extract Created in Mash / Max Potential Extract Wt​
Max Potential Extract Wt is calculated as shown in post #9 in this thread:
Max Extract Wt = Weighted Ave % Extract Potential [FGDB] * (1 - Weighted Ave % Moisture) * Total Grain Bill Wt​

SG in °Plato is defined as Weight% extract in the wort, and is given by:
°P = 100°P * Extract Wt / (Extract Wt + Water Wt)​

The maximum SG the wort in the mash can achieve is:
Max Wort °P = 100°P * Max Extract Wt / (Max Extract Wt + Strike Water Wt)​

And the SG actually achieved in the mash is:
Actual Wort °P = 100°P * Actual Extract Wt / (Actual Extract Wt + Strike Water Wt)​
We can solve the above formula for SG for Actual Extract Wt. if we know the SG:
Actual Wort °P * (Actual Extract Wt + Strike Water Wt) = 100°P * Actual Extract Wt​
Actual Wort °P * Actual Extract Wt + Actual Wort °P * Strike Water Wt = 100°P * Actual Extract Wt​
Actual Wort °P * Strike Water Wt = 100°P * Actual Extract Wt - Actual Wort °P * Actual Extract Wt​
Actual Wort °P * Strike Water Wt = (100°P - Actual Wort °P) * Actual Extract Wt​
Actual Extract Wt = Actual Wort °P * Strike Water Wt / (100°P - Actual Wort °P)​
We can now substitute the formulas for Actual Extract Wt and Max Extract Wt into the formula for Conversion Efficiency:
Conversion Efficiency = (Actual Wort °P * Strike Water Wt / (100°P - Actual Wort °P)) / (Weighted Ave % Extract Potential [FGDB] * (1 - Weighted Ave % Moisture) * Total Grain Bill Wt)​

or, to get it all on one line:
Conv Eff = (Wort °P * Strike Wt / (100°P - Wort °P)) / (% Extract Potential * (1 - % Moisture) * Grain Bill Wt)

The above formula uses two things most homebrewers don't deal with: SG in °Plato, and water weight. A couple of formulas can convert from water volume to water weight, and °P to SG in "normal" form (i.e. Density of Wort / Density of Water = 1.0xx.)

Water weight is just Water Volume * Water Density, where both values are measured (or corrected to) the same temperature. At 68°F (20°C) water has a density of 8.3304 lb/gal or 0.9982 Kg/L. So, calculate your strike water weight as:
Weight in lb = Volume in gal * 8.3304 lb/gal
Weight in Kg = Volume in L * 0.9982 Kg/L
The usual equation for converting SG to °P is:
°Plato = (-1*616.868)+(1111.14*SG)-(630.272*SG^2)+(135.9975*SG^3)
You can copy the above formula directly into a spreadsheet, and replace "SG" with the cell address containing the SG value.

Another potential issue is having grain potentials only in SG format (1.0xx). Table sugar (sucrose) is the reference for 100% potential, as 100% of the material goes into solution. In SG format sucrose has a potential of 1.0462. To convert a potential in SG to % use:
Potential % = 100% * (Potential SG -1) / 0.0462 (or ppg / 46.2)​
Brew on

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
I agree that hardly anyone computes conversion efficiency, but it can be done, using the strike water volume, the grain weights and extract potentials, and the gravity at the end of the mash (i.e. before sparging/lautering). And if you know Conversion efficiency and Mash efficiency, you can compute Lauter Efficiency from them. I'd be surprised if @doug293cz hasn't posted the whole suite of formulae somewhere in the forum.
I have discussed the different efficiencies (conversion, lauter, mash, brewhouse, packaged) many times on HBT, but I don't think I have ever previously posted the straightforward math to actually calculate conversion efficiency - I just referenced Braukaiser's page. Braukaiser's math only works for metric units, and he doesn't use the temperature corrected water density (even for metric.) I have posted previously a sloppy way to calculate conversion efficiency, that I wrote before really understanding the math. It works, but no one would call it elegant. I wouldn't want to help people find it with a link.

I have thought about writing a long post on efficiency that combines all the information that I have posted in various places. Maybe it's time to actually do that. Would it be gauche to sticky my own thread?

Brew on

#### VikeMan

##### It ain't all burritos and strippers, my friend.
I have thought about writing a long post on efficiency that combines all the information that I have posted in various places. Maybe it's time to actually do that. Would it be gauche to sticky my own thread?
I wouldn't mind seeing it. I'd likely pinch some of it to enhance my brewclub presentation on efficiency.

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
Over the past 3 years of reading thousands of posts, I have never seen a thread that even mentions conversion efficiency. I think it is just assumed to be 100% as anything less implies your mash did not convert all the starches which should not happen unless something serious goes wrong during the crushing/mashing process (poor temp control, too short, not enough diastatic power, very bad crush, etc). Also, it would be impossible to calculate as it would be impossible for a homebrewer to determine if the poor mash efficiency is due to poor conversion or poor lautering. Basically, nobody really bothers with conversion efficiency as it is just assumed to be 100% or if not something went very wrong in the mash.

You must not read many of my posts. I can't remember how many times I have posted about conversion efficiency, and how it interacts with mash and lauter efficiency.

In actuallity, low mash efficiency is very often due to low conversion efficiency - which is often caused by too coarse a crush for the mash time used (incomplete gelatinization usually.) As @Gnomebrewer covered, it is important to be able to separate conversion and lauter efficiency when diagnosing low mash efficiency - you need to know where the problem resides in order to remedy it.

Your questions suggests that a clarification of the "why" mash efficiency and "brewhouse efficiency" matter and how the basis of how they are derived would help you with the formulas, which are actually quite simple if the higher level concepts are clearly understood.

You should always achieve 100% conversion of your mash, otherwise you will end up with unfermentable starches in your beer. In other words, practice good mashing and grain bill practices and you will hit 100% conversion every time. Don't bother worrying about calculating it.

Actually, most brewers do not achieve 100% conversion efficiency. With proper conditions and mash time, you should be in the 95% to 100% range. Even in a Congress mash, the coarse grind conversion potential is usually slightly lower than the fine grind potential, and this is entirely due to lower conversion efficiency.

Brewers capture mash efficiency (or lautering efficiency mentioned above) because it tells them how much of the potential available sugar locked in the kernel was extracted during the mash and ended up in their kettle. This is especially important for commercial brewers as malt is a significant portion of the cost of making beer. In other words, poor efficiency means they are pouring money down the drain - literally. From a home brewer perspective, as long as you hit your target mash efficiency and extracted the sugar you need to hit your target OG, then having a low mash efficiency only means you spent a couple more dollars on grain. Many home brewers are proud of their mash efficiencies often sharing that they got a very high number, but in reality it is not very relevant as long as it is reasonable (say 70 - 80%). What is relevant is that you understand your systems mash efficiency so you can calculate how much grain you need to hit your starting gravity every time.

Please do not confuse other brewers by conflating lauter efficiency with mash efficiency. They are most often not the same.

Brewhouse efficiency is just like mash efficiency except it takes into consideration further sugar losses downstream of the kettle and up to the fermenter, like the wort and trub left in the kettle after racking to the fermenter, which is where realized OG or starting gravity is captured. Just like mash efficiency, commercial brewers care deeply about this as any sugars that do not make it into the fermenter is just money down the drain. The impact of lower brewhouse efficiency on a home brewer is just a few more bucks per batch and it is up to the brewer to decide if the few dollars matter.

So the formula to calculate either mash efficiency or brewhouse efficiency is really just a matter of calculating the max available sugar points locked in your grain bill and the sugar points that made it into your kettle (last two digits of preboil specific gravity * volume) or fermenter (last two digits of OG * volume). Then just divide the realized points from the max available points.

Brewing software packages have databases of max available sugar points for each grain. You can also find the numbers on the internet. There is a lot that goes into the calculation of max points per pound per gallon, like dry basis vs as-is, coarse vs fine grind, which you can dig into if you are interested, but just knowing a published number should suffice for the calculations you seek.

Finally, conceptually brewers are consistent on the usage of mash and brewhouse efficiency. However, the max points calculation may not be consistent across brewers as how grind, dry vs as-is basis and other factors used in the calculation are sometimes applied differently, so just stick with a consistent set of max available points and then determine your systems mash efficiency so that you can apply it against max available points and hit your target OG every time.

Brew on

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