# Formula For Efficiency Calculations



## boobiedazzler (3/6/10)

Can anyone tell me what this final figure is called, when calculating efficiency ? 

Total Volume x OG / Grain Weight = X

For example 23 Litres x 46 (or 1.046 OG) / 5 (Kilograms grain) = 211.6

And how does that relate back to a % brewhouse efficiency?


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## Sammus (3/6/10)

You need to know the potential yield from your grain. They do special lab tests with each grain and determine a maximum potential yeild (ie 1.010 per kg per L or something - this probably isn't even close to a real figure, but is just there for an example). Then you figure out what the maximum potential yield is for a given grain bill and final volume. Then you take your OG and final volume as a percentage of the potential one. Take your OG readings and volumes in the fermenter. That's your brewhouse efficiency (ie taking into account all kettle and chiller losses etc). Some people like to quote the volume and OG before they do any transfers and thus not counting any losses. That's the way the big noters take it so it sounds like they have more epeen than the people doing it honestly.

I've never seen the forumla you used before, and not sure how it relates to efficiency.


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## katzke (3/6/10)

boobiedazzler said:


> Can anyone tell me what this final figure is called, when calculating efficiency ?
> 
> Total Volume x OG / Grain Weight = X
> 
> ...



Looks like an extract number per kilo of grain. Only would help if you know the potential of the grain per Kilo.

Brewhouse efficiency may not be the term you are looking for. I hate the term, as it does not say when in the brew house you are checking. I like to use mash or pre-boil efficiency as it tells if you mucked up the most important part. From there each brew can have a different efficiency as hops suck up wort. Different grain bills can also create more trub.

I also do not worry too much as long as I get a brew with a gravity and volume as close to expected as possible.

Can not help from there as I do it all different being in the USA and using gallons and pounds.


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## boobiedazzler (3/6/10)

I like the fact that I can get an easy number to measure a brew day against, and appreciate the homebrew shop guy taking the time to show it to me. But sure I can see how it's imperfect if using a variety of brands. The point that I enjoy is that for repeatable recipes, it does appear to have some relevance in relation to efficiency, with the magic variable being in the post-boil OG figure. 

Thinking out aloud here - but then again, it's ONLY the OG that's the key in repeatable recipes, so yea, what's the point of this formula LOL? 

Building a spreadsheet today to keep track of my brews, so what is the formula for efficiency, if I have the grain potential data ? I want to work out a common figure that is relevant across a range of recipe styles, to see how well the process has been.


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## boobiedazzler (3/6/10)

FWIW, I will be using JW Ale malt exclusivly for a base. 

But would also need to know the data on cooked rice, and also the efficiency drop on home-toasted base malt. 

Damn, the theory behind this hobby is serious business.


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## Sammus (3/6/10)

(measured OG-1)/(potential OG-1) * 100 = efficiecny %

That's assuming the volumes are the same. The potential OG is dependant on the target volume, so if your volumes are different you also need to multiply it by (your volume)/(target volume). the minus one is because we only care about the points, ie the '40' in 1.040.

So the excel forumla might look something like

((mOG-1)*(Vol*100))/((pOG-1)*tVol)

where mOG = measure OG, Vol = your final volume, pOG = potential OG, and tVol = target Volume.

For example, if your grainbill has a potential yeild of 1.060 for 25L, and you end up with 28L of 1.040, then you got a lower og, so you you think your efficiency is is much lower, like 40/60 = 66.6%. But then you got more volume than you were meant, so that adds a factor of 28/25 = 1.12. So your overall efficiency is 4/6 * 28/25 = ~74%. Or all in one step

(40*28*100)/(60*25) = 74.67%

Get a program like beersmith, it does all this for you, and has most of the potential yeild data already in it. And it keeps records of everything you do if you make it


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## boobiedazzler (3/6/10)

Many thanks Sammus, but to step back one notch, how do you calculate potential in order for your formulae to work? I visited the Joe White website, but they don't offer their analysis on maximum potential yeild. 

Not trying to reinvent the wheel, but would prefer to get the data into my head instead of using software, mostly as a self educational understanding. Plugging information into Beersmith wont tell me how it comes to a figure.


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## katzke (3/6/10)

boobiedazzler said:


> Many thanks Sammus, but to step back one notch, how do you calculate potential in order for your formulae to work? I visited the Joe White website, but they don't offer their analysis on maximum potential yeild.
> 
> Not trying to reinvent the wheel, but would prefer to get the data into my head instead of using software, mostly as a self educational understanding. Plugging information into Beersmith wont tell me how it comes to a figure.



I think beersmith calculates based on gallons and pounds even when you are using metric units.

Didnt someone make up a spreadsheet that works in metric units and Australian Malts?

This may be more then you want to know. http://www.braukaiser.com/wiki/index.php?t...ouse_Efficiency


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## Sammus (3/6/10)

boobiedazzler said:


> Many thanks Sammus, but to step back one notch, how do you calculate potential in order for your formulae to work? I visited the Joe White website, but they don't offer their analysis on maximum potential yeild.
> 
> Not trying to reinvent the wheel, but would prefer to get the data into my head instead of using software, mostly as a self educational understanding. Plugging information into Beersmith wont tell me how it comes to a figure.



Ah that's why I like the software 

The potential yields aren't usually readily available, and tend to vary slightly batch to batch. I've attached a sample spec sheet for some other pale malt I came accross. Can't even remember what it's for, I think maybe barrett burston, but you can see the extract potentials at around 80%. I think that means that 80% of the weight is potentially sugars, so for each kilo of malt you can get up to 800g of sugar out of it. Not sure where to go from there, I'm sure someone else may be able to step in  I know that 100g of malt extract in 1L of water gives about 1.040, so maybe that means that 80% extract potential means that you get about 800g per kg, so in 1L that's 800g per L which should give about 1.320 per kg per L.

so 5kg in 20L would be 320*5/20 = 320/4 = 50 points, or 1.050SG

Sounds about right 

View attachment BN204603_2290_9_BB575_81.70MT_Pale.pdf


disclaimer: there's probably a simpler way for doing it that what I'm describing, MHB has told me how to do it easily a million times before, I forget though haha. Shoot him a PM and he'd probably be happy to help out.


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## barneyb (3/6/10)

Grain and malt specs (inc joe white)
http://www.aussiehomebrewer.com/forum//ind...;showarticle=26


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## katzke (3/6/10)

You can either use the % figures or the extract numbers to do the calculations.

One advantage to the % numbers is you could set your spreadsheet to use a target gravity and a house efficiency and then give the grain bill in % and have it calculate the amount of grain in Kilos for you. Not may people do this so it may be harder to set up recipes. That is one thing on my list of to dos, add % calculations for the malt bill to the spreadsheet I use.

I looked at Craft Brewer and they give malt specks several ways. If you want to use extract numbers, a pale malt I looked at was 308. Using this number you would take the Kilos X 308 X your efficiency = Liters X the last 2 numbers of your expected efficiency. If you have a malt bill with more then one malt then you need to figure the sugar for each malt and times that by your efficiency. In that case you need to be a bit of a spreadsheet expert to catch all the malt entries and not get a math error.

The problem comes with what number you use for the Liter amount for when in your process you want to figure your efficiency. If you want to get a gravity at the end of your ferment or in the bottle or glass you need to take all the losses into account. I have adapted my spreadsheet to give a boil gravity as well as the final gravity of my fermented beer. I am still tweaking my liquid volumes but am getting close.

As you may tell this all depends on how well you measure and how honest you are in all your losses. Hops are the big thing and I am working on getting that nailed down. A simple ale will have less loss to hop absorption then a wild hopped American IPA.

A side note to making a spreadsheet for brewing is to make sure and allow for heat shrinkage and boil off. I know men are not willing to talk about things shrinking when they get cold but at times it is important.

If you want to get an idea of what to do in a spreadsheet look for SUDS. It is a spreadsheet as well as a stand alone program. You may get some ideas from it as to how to set up your sheet. It is setup for pounds and gallons so the hop calculations may be difficult unless you do a metric conversion. You may be able to find hop calculations in metric. Look at the link I posted earlier as I think it had hop calculations as part of it.


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## warra48 (3/6/10)

This is copied some time ago from a post on this forum by Jayse. I can't find the thread anymore. I have edited it slightly to make it more readable and to fix spelling errors etc.
The potential extract figures are averages or ball park figures, but they are close enough for our purposes as homebrewers.
Hope it helps to give you a basic understanding of mash efficiency.

MASH EFFICIENCY

Brew maths is really quite simple.

How it works is all malts and adjuncts etc give a different gravity. 
The specifications are all written as H.W.E which is "hot water extract", with sugar being the highest at 386, so everything else is given as a % of that. ie, pale malt is around 81% which gives you around 309. 
This is the total gravity you can get with 1 kilo in 1 litre but it is impossible to get this, this is 100% efficiency.
The same goes for American calculationss but its in P.P.G which is the gravity of 1 pound in 1 gallon. The same specs are used ie. 81% for pale malt gives you 37 points of gravity.

So a simple example to work out the total potential for 5 kg of pale malt in 23 litres is
5 x 309 / 23 = 67 (1.067)

Now to work out your efficiency you divide the gravity you achieved with this brew. Say you have 1.050 so 50/67 =.74 so you achieved 74% effiency.
Then next time when you do the calc. 5 x 309 /23 =you simply times this by .74 .
This gives you your expected gravity.

For your first batches I would stick to using about 65 to 70%.
So do the 5 x 309/ 23 = 67.
then times 67 by .65 = 43(1.043)

PS: the HWE numbers are usually all on the malt craft sites. Other malts like crystal malt are around 75%. Some malts can be lower and some higher.
To get the number times 386 by the percent as a decimal point ie pale malt at 81% gives you 386 x .81 =312 

Ale -------81% X 386 = 312
Pilsner----------------81%
Hoepfner Munich----80% 308
Melanoiden--------- -80%
Caramalt pils---------79% 305
Crystal---------------- 75%

Well, it's the method you will see in Australia. 

Say the HWE is 308 litre degrees per kilogram for a malt. 
That means 5kg in 20L will give you : (308 x 5)/20 = 77. i.e. 1.077 SG at 100% efficiency. Multiply that by your efficiency (eg. 75%) gives you 77 x 0.75 = 57.75 or close enough to 1.058.


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## MHB (3/6/10)

> katzke
> 
> Brewhouse efficiency may not be the term you are looking for. I hate the term, as it does not say when in the brew house you are checking. I like to use mash or pre-boil efficiency as it tells if you mucked up the most important part. From there each brew can have a different efficiency as hops suck up wort. Different grain bills can also create more trub.



Actually the Brew House Efficiency is the one truly vital number. It is the measure of exactly how much extract you have in the fermenter at the end of brewing / the potential, or what you could have got if you achieved 100 % extraction and had no losses.

This is a copy of a doc I gave out after a talk at a HUB meeting. It uses the more modern EBC method of calculating efficiency and looks at Plato, was written for a mixed audience of Kit, Extract and Mash brewers.

MHB



Gravity​In brewing everything dissolved in a wort is referred to as extract. Gravity is the term we use to define how much is in solution. Over the years there have been several ways to look at gravity the two most commonly used by brewers today are:-

Specific Gravity (SG) Is simply a comparison between a sample and the the weight of the same volume of water, (working in metric makes this all so easy) we know 1 Litre of water weighs 1 Kg, if a Litre of wort weighed 1.050 Kg we can say it is 1.050 times heavier than water or it has a SG of 1.050.
Plato (Po) - (there is a good overview in Wikipedia)
Plato is a more refined version of Brix which is an even more refined version of the earlier Balling scale, and is simply a comparison to a known sugar solution. If a wort has the same density as a 10% w/v (10% weight/volume i.e. 100 g in a litre) solution of common white sugar it is referred to as being a 10 Plato (10 Po) wort.
It's important to note that the density is dependent on temperature and that you must know the temperature at which your equipment is calibrated (in Australia it's mostly 20o C).
In brewing everything that goes into solution is called "Extract" that includes sugars, proteins, minerals and fatty acids.
Density measures everything in solution; it doesn't tell you anything about what is in solution, just how much.
It's very important to note that water included in anything added to a wort doesn't add to the extract, just the volume.
Given that there are two common scales, I suppose the obvious question is why two and how they are used, but first how they relate to each other.
Unfortunately the exact relationship is fairly complex but across the common brewing range (1.006-1.060 ish) there is a pretty good approximation roughly: -
SG = (Po * 4)/1000 +1
Or if you want be really precise these equations are good to more than 5 decimal places.
Po = − 616.868 + 1111.14(SG) − 630.272(SG)2 + 135.997(SG)3
SG = (668- (6682 820(463 Po)2)/410
Let's say you are making a fairly simple kit beer with just a 1.7 Kg can and 1 Kg of dextrose
What would the O.G. be? (OG being the term for the gravity at the start of fermentation or Original Gravity)
First up the kit is going to be about 80% solids and 20% water so the kit will add 1.36 Kg of extract to the wort.
Dextrose is roughly 10% water (dextrose monohydrate) so 1 Kg will add 0.9 Kg of extract.
In total you are adding 2.26 Kg, if the wort is made to a standard 22.5 Litres the Po of the wort is going to be (2.26/22.5) * 100 = 10 Po
Using the quick formula above the O.G. will be:-
OG = (10 * 4)/1000 +1 = 1.040
Frankly that's piss weak, I want an O.G. of 1.055 so I have to add 0.015 to the gravity. By running the equation in reverse we can work out how much to add.
Or just look at the Po we want
1.055 = (Po * 4)/1000 +1 = (0.055* 1000)/4 = 13.75 Po
We have 10 Po so we need to add 3.75 Po (or 3.75% w/v) to 22.5 litres 22.5*0.0375 = 0.84375 Kg of dextrose?
Not quite, remember dextrose is 10% water so to get the right amount of extract we add 0.84375/ (90*100) = 0.9375 Kg of dextrose
Having met just a few brewers I reckon most of them would dump in the whole kilo and be done.
It's fairly clear that a basic knowledge of SG and Plato gives you very good idea of what you will get when you are designing a beer.
If you are a mash brewer it goes a step further and in practice you work backwards from what you want to what you need.
Just taking the simplest possible single malt All Grain (AG) recipe say you want an O.G. of 1.050, you want to make 22.5 L and there will be 2.5
Lleft in the bottom of the kettle with the trub.
All the extract that doesn't end up in the fermenter is lost and is accounted for as part of "Brewhouse Efficiency" (BhE) but is important to highlight the fact that it contains extract to, once you have established what your losses are you can just use the Brewhouse Efficiency.
1.050 SG is about 12.5 Po so we need 12.5% of 22.5 or 2.8125 Kg of extract into the fermenter.
If our BhE is 70% we need to make a total of 
2.8125 /70*100 = 4.0178 Kg of extract
If our malt had a potential yield of 79% we would need 
3.65625 /79*100 = 5.0859 Kg of malt
So you will be buying 5.1 Kg won't you?
Plato obviously makes a lot of sense and people often ask why it isn't the only scale we use. Well its great before fermentation, it stops being so sensible after the yeast gets to work.
Alcohol has a lower density than water, obviously much lower than Wort, trying to relate the amount of residual extract, alcohol and water really isn't the job for Plato but it's where SG excels!


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## Sammus (3/6/10)

MHB said:


> <snip>
> 
> If you are a mash brewer it goes a step further and in practice you work backwards from what you want to what you need.
> Just taking the simplest possible single malt All Grain (AG) recipe say you want an O.G. of 1.050, you want to make 22.5 L and there will be 2.5
> ...



That was absolute gold. Except the last calculation you say "If our malt had a potential yield of 79% we would need 
3.65625 /79*100 = 5.0859 Kg of malt" = where did that 3.65... come from? 

edit: Pretty sure it's a cutnpaste error since 4.0178/79*100 = 5.0859


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## MHB (3/6/10)

Yea well spotted at least you read that far

Sorry about that I did the calks in an Excel Spreadsheet and must have copied the wrong cell, as its the right answer.

Mark


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## katzke (4/6/10)

MHB said:


> Actually the Brew House Efficiency is the one truly vital number. It is the measure of exactly how much extract you have in the fermenter at the end of brewing / the potential, or what you could have got if you achieved 100 % extraction and had no losses.



That is the correct definition, as I understand it. And so a set number is not possible because of the reasons I gave earlier.

That is why I look at my mash or pre-boil figures. It tells me how the mash went and if I need to do anything to make adjustments to my brew. Once I start adding hops the brew is mostly set. My mash efficiency will be a more stable number then my house efficiency. Also if I can predict my mash efficiency and my boil off rate then the other losses have no effect on the gravity of the wort. They only reduce the volume. Hop additions are also only dependant on the same volume calculation. Any losses other then boil off have no effect on the hop rate. To clarify the other losses I refer to are all losses that happen after the wort is in the kettle and ready to boil. All of these losses are dependent on the grain bill, hop amounts and type, and yeast type.

I only bring this up as the OP said they wanted to work up a spreadsheet to figure out recipes. Every loss in brewing is either predictable or can be measured for a particular brewery. When it comes to calculating gravity not all the losses are important. They only effect the final volume of wort. If the final volume is used in predicting gravity a big surprise awaits the brewer if the calculations are not included for all the possible losses to get to the same number one has after the mash or preboil. Using a post boil number introduces issues of allowing for hop material in the volume calculation.

Accounting for the losses in brewing software is important. We all start by saying we want to brew so much beer. The brewer or the software needs to know how much water is needed to get the end volume. All this I am typing is trying to say that once that number is calculated the final volume will not actually be correct when the brew is done. Unless you have your software nailed and your system nailed. The best example I have is a lightly hopped beer will end up with a larger final volume then a highly hopped IPA. No software I know takes into account the wort loss to hop rate.


Brewhouse efficiency is a good number to know. It just is not all that important and darn hard to predict from brew to brew unless you brew that same recipe all the time. I do not even worry about others efficiency as if you give me a recipe with a SG and a FG, IBU, hop and gain bill, yeast, and any other important additions, I can work it out for my system. I do not even need a volume as the grain bill can be converted to %. Hops are easy to convert also if the IBU is given.

After all that use whatever number you need to make your brew happen. In my case I am modifying the SUDS spreadsheet to work with BIAB and take into account losses to hop absorption. I hope to never have the surprise of brewing a ridiculously hopped IPA and finding my volume way lower then expected because of all the hops in the kettle sucking up wort.

For the OP. All your calculations depend on good figures from your measurments taken from your system. It is important to take time when brewing to actually and accurately measure things like grain absorption and boil off. Other losses like what you leave behind in the kettle are important to get correct. After all that you will get reasonably predictable final volumes.


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## pokolbinguy (28/11/11)

Hey Guys, 

Anyone able to do a quick efficiency calculation for me. I dont have the forumla(s) in front of me (unless they are in this thread....god I'm being lazy tonight) and to be honest don't want to spend all night at it. I would really appreciate it.

Dr Smurto's GA.

2.4kg Pils
0.8kg Muchich I
0.8kg Wheat malt
0.25kg Caramunich I

ended up with 18L @ 1038 (will dilute before pitching)

Cheers, Pok


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## pokolbinguy (28/11/11)

Please....


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