The formula is;

(Wort gravity (expressed as points) x Wort Volume (Litres) X 100) / Extract potential (expressed as Kg/L) X grain bill ( In Kg )

So if you have 37.7 L of wort ofter mashing at a gravity of 1.038 from using a grain bill of 5.975kg with an extract potential of 307/Kg/L you will get:

38x37.7x100 divided by 307 x 5.975 which gives you 78.09957341% rounded to 78.1%.

[EDIT: Bloody Yeasty - wrote the below while he was posting . The below is a lot longer explanation which may clear a few things up or confuse you - hopefully the former . In a later post I'll explain the difference between the kg/l Yeasty has used and the ppg I have used below.]

Good question wbosher. I might need a coffee to answer it though ,

Firstly, 'mash efficiency' is probably another one of those terms to avoid as it is a bit unclear. For example, some traditional brewers may take it as meaning the efficiency of their mash without the sparge. Others may take it as efficiency into kettle.

Let's call it 'Efficiency into Kettle' or EIK. Other valuable efficiency measurements are, 'End of Boil Efficiency' (EOBE) and, less so, 'Efficiency into Fermentor' (EIF).

To calculate any efficiency figure, three inputs are needed....

Volume

The thing to consider here is the temperature of the wort. For example, if you take a reading at the immediate start or end of the boil, you'll need to multiply that number by 0.9614 to allow for the wort expansion that occurs. Another option, in a full-volume BIAB, that can be easier is to measure the volume after you have pulled the bag and then multiply it by 0.9806. The reason this is easier is that the wort is not 'jumping' around at mash temps like it does at the boil.

Let's assume you took a volume reading just before the boil that read 34.1 litres or 9.0 gallons. Multiply this by 0.9614 and we end up with a pre-boil volume adjusted to ambient of...

32.78 L or 8.66 Gal

Specific Gravity

No explanation needed on this one. Just take your gravity reading ensuring that your sample is cooled to ambient temperature, or better still, the same temp as your hydrometer is designed for (15 or 20 C).

Let's say your reading says 1.036

Extract Potential of your Fermentables

What I think I'll do in this post is just the basics of extract potential and do a separate post with more detail as it is a confusing area. For example, the terms FGDB, MC, FGAI(%) and FGAI (ppg) all need to be explained. The critical 'extract potential' number we are after is FGAI (ppg).

FGAI (ppg) is the number that a fermentable 'scores' after going through a certain type of laboratory mash. In the case of a grain, this varies from batch to batch and grain type to grain type. A good 'average' ppg figure for grain is 35.49 ppg. (Sorry for the decimal points but I am working off some numbers I know.)

To keep this example simple, I am going to say that we have only used one grain in our grain bill and that it's FGAI in ppg is 35.49.

[center]Total Gravity Points[/center]

ppg means specific gravity points per pound per gallon. Let's assume our grain bill is 4420 grams or 9.75 pounds, then if we were 100% efficient, we would expect...

9.75 pounds * 35.49 ppg = 346 gravity points

Let's see how many gravity points we actually scored. To do this we multiply the volume in gallons we measured by the specific gravity we measured i.e....

8.66 gallons * ((1.036 specific gravity - 1)*1000) = 8.66 gallons * 36 ppg = 312 gravity points

[center]What was our EIK?)[/center]

Once we have the above two numbers, our Efficiecny into Kettle is simply as follows...

312/346*100 = 90.2%

[center]Some other Important Points[/center]

As mentioned, I'll go more into the extract potential side in another post which I won't have time to write now. The above is probably enough to think about for a while anyway.

The most important things about efficiency figures to understand is...

1. That like any measurement on a brew, a single reading is not going to tell you much. For example, EIK and EOBE should theoretically equal each other on the same brew but rarely will you find they agree. Never rely on one or two readings. It's only if you see a pattern of low or high readings that you should start to make adjustments, question your practices or your grain quality.

2. Assuming you have kettle trub as we all do, EIF should be lower than EIK or EOBE. How much lower it is reflects how much trub you had in the kettle.

3. Efficiencies should vary according to the original gravity of the recipe. If you are brewing a recipe with an OG of 1.070, you should expect far lower efficiencies than if doing a recipe with an estimated OG of 1.040.

Hope the above isn't too confusing wb. Let me know what doesn't make sense.

PP, In Australia and the Land of Oz, you guys use POUNDS?? and GALLONS????

I thought was "Points per Liter per Kilogram" The same thing, only different except The conversion factor between ppg and L°/kg is 8.3454 x ppg = L°/kg.

see http://morebeer.com/brewingtechniques/l ... nning.html and
http://www.mashspargeboil.com/a-guide-t ... fficiency/

(Josh, you actually don't see L°/kg here much. Anyway, below I am going to try and put things together a bit.)

Like most areas of brewing, the lack of standardisation makes things very confusing. You can see this from the metric versus imperial posts we have had here already. It actually gets even more confusing. For example, extract potential can also be expressed as a percentage. I'm going to try and tie all these together towards the end of this post.

Before we even get there though, we have to address the laboaratory methods and some of the terms used that relate to extract potential. I am not even going to mention some of the methods of measurement such as CWE (used by some British Maltsters) and will only touch on coarse grind as I think the below is bewildering enough for most brewers .

This extract potential area is a great example of how ridiculous non-standardisation is and how rife it is in the brewing world. Drives you mad!!!!! Are you still with us wbosher?

Here's Part 2...

[center]How do I Find out the Extract Potential of a Fermentable?[/center]

Unfortunately there is no common standard (let alone language) used by maltsters of different countries let alone in the same country to describe the extract potential of a grain. Perhaps the easiest things to keep an eye out for in most malsters specs are the following...

MC - Moisture Content

All grain contains some moisture. Four percent is a rough average. So, if we bought 100 kgs of grain and dried it out, we'd end up with 96 kgs of pure grain matter. Grain that has been dried is referred to as being on a "dry basis". Grain that has not been dried is termed, "as is."

Nearly all laboratory tests use grain that is on a dry basis.

FG or CG - Fine Grind or Coarse Grind

To confuse us even more, a few malsters use grain that has been coarsely ground instead of finely ground. A coarse grind is seldom used so I suggest we don't even address it here. Just be aware that if you ever see anything like CGDB or DBCG, it means Coarse Grind Dry Basis.

FGDB versus FGAI - Fine Grind Dry Basis versus Fine Grind As Is

Putting the above information together, you will often see the shorthand FGDB and MC in grain specs. FGDB (or DBFG - note that there is no standard in these extract potential terms as to whether the grind or the basis is written first) means a fine grind was used on grain that had been dried for the laboratory extract potential test.

As we are not using dry grain in our brew, we must convert FGDB to FGAI. You do this as follows...

FGAI = FGDB * (100 - MC)/100 eg 96 = 100 * (100 -4) / 100

[center]FGAI - Imperial, Percent or Metric?[/center]

In my posts here, I have only referred to the extract potential of a grain or fermentable as being expressed in ppg. As mentioned first thing in this post, a maltster may also choose to express extract potential in metric or as a percentge. Let's firstly look at what ppg means...

PPG = Gravity Points per Pound of Fermentable Per Gallon

What this is saying is that if the extract potential of a fermentable was say 37, then if you put a pound of this fermentable into a gallon of water and then checked the gravity with a hydrometer, the hydrometer would read 1.037.

Note that sucrose is regarded to have an extract potential of 46.214 points. So if you dissolved a pound of dry sucrose in a gallon of water, your hydrometer should read 1.046.

Percent = Extract Potential when compared to Sucrose

We saw above that sucrose's extract potential when expressed in PPG is 46.214. Sucrose is considered to be fully fermentable and therefore if it's extract potential is expressed as a percentage, it is expressed as 100%.

If we know the extract potential in ppg but wish to express it as a percentage, we simply divide it by 46.214 and multiply by 100. So, if our specs said our grain had an extract potential of 37 ppg then it's extract potential as a percentage would be...

37 / 46.214 * 100 = 80.1%

Metric - L°/kg (referred to as HWE or Hot Water Extract)

Unfortunately, here again we see no correlation in logic to the imperial ppg. L°/kg means how many litres of wort with a specific gravity of 1.001 you could produce from a kilogram of the fermentable .

For example, if you had a kilogram of sucrose, you could make up 386 litres of wort with a specific gravity of 1.001.

To convert L°/kg to a percentage, divide it by 386 and multiply by 100. For example, if your grain had a L°/kg of 309, then it's extract potential as a percentage would be...

309 / 386 * 100 = 80.1%

Expressed in ppg, it would be 80.1% * 46.12 = 37

See how joshua's post above also relates to this? 309 / 8.3454 = 37

...

Wouldn't it be nice if all specs were just expressed as a percentage using the same laboratory method?

A Few More Things

1. The only way to get true specs is to get a copy of the specs that came with a batch of malt. Every batch of malt varies and you'll find it hard to get a hold of the specs for all the fermentables you use.

2. Whilst the Calculator doesn't allow for the input of individual fermentables extract potentials, the default average works quite well unless you have a large amount of sugars in the recipe. The BIABAcus, which will replace The Calculator, does allow you to over-ride the default average for every individual fermentable however, for an all-grain recipe, especially considering 1 above, I wouldn't bother doing this. It doesn't make that much of a difference.

3. Be aware that some popular brewing software has extract potential wrong. For example, one does not account for moisture content so their gravity predictions are about 4% out straight away. From memory, the same program 'forgets' to shrink the wort on their pre-boil gravity meaning that EIK reads higher than it really is. So, there are a few errors out there.

I know we haven't even looked at adding up all the individual extract potentials in a grain bill. The above examples have just assumed a single fermentable. Let me know if you want an example of working out a full grain bill's extract potential and I'll write one up but won't have time to do so for at least several days.

Fun and games ,
PP

Very informative PP

PistolPatch wrote:Unfortunately, here again we see no correlation in logic to the imperial ppg. L°/kg means how many litres of wort with a specific gravity of 1.001 you could produce from a kilogram of the fermentable .

For example, if you had a kilogram of sucrose, you could make up 386 litres of wort with a specific gravity of 1.001.

Interesting. Silly and bass ackwards, but interesting. I had never heard that before.

PistolPatch wrote:Let me know if you want an example of working out a full grain bill's extract potential and I'll write one up but won't have time to do so for at least several days.

I'd like for you to do that. But I want a really complicated grain bill, something like 10 different malts should do. And could you please show all the steps? Thanks!

In case the sarcasm didn't come through on the post above...don't worry about the calculation

wb, I think there are only a few main points to get out of this initially, perhaps ever. The first one is psychological and BrickBrewHaus being one of the BIABAcus betas will back me up on this.

Psychological

BBH mentioned his sarcasm above and you would have seen a few eye rolls in my posts above. Why? Whether it be extract potential, colour, IBU's or whatever, the lack of common standards and terminology makes things pretty ridiculous. Errors in existing software compound the problem. There are literally hundreds and hundreds of posts in the hidden beta sections of the forum that have waded through the mess and tried to make it more understandable. It shouldn't be that hard. We even see it in competitions. One country uses a system of 20 points while another might use a system of 50 points giving more or less weight to certain things. We brewers can even make the most simple stuff muddy.

What I am trying to say here is that if you see something in brewing terminology or mathematics that seems to lack some basic logic or maybe even looks wrong, it probably is. If you think that something could be made much simpler, it probably can. Getting over this shock of how poor standards and terminology are is hard on the brain. Once you are over this, you then get hit with the second shock of how common errors are in brewing software. In reality, you are usually absorbing both of the above shocks at the same time .

For me personally, studying this side of brewing has always been like watching a really bad movie that you think can't get any worse. It does . And some of us still keep watching - lol!

What actually is Efficiency?

Put simply, an efficiency measurement is just a measurement of how many 'sugars' you have managed to keep in your wort, at various stages of the brewing process, as compared to the sugars retained in a highly efficient laboratory mash.

There are several formulas that can be used to calculate efficiency but they all are essentially based on the weight of 'sugars' in the wort.

...

BBH joked about doing a complex example with all the steps . I think I actually will do this, not so you can learn and understand the calculations but more so that you can plug in the grain bill example into existing software and check the answers. In a lot of software, the terminology is so vague, you won't even be able to check the answers!!!

Having a baseline, certainly won't do any harm.

Apologies too that my writing style in areas like this might seem a bit authoritarian or 'know it all.' I'm not sure how else to write this stuff though. The danger of writing in this style is that the reader might assume that there is no possibility of error. There is so please let me know if you think I have buggered something up.



P.S. There's a chance my job today is going to be postponed. If so, I'll have a crack at Part 3.

PistolPatch wrote:P.S. There's a chance my job today is going to be postponed. If so, I'll have a crack at Part 3.

What !! There's more... I still like my answer the best

Yeasty,

You should never do something Simple and Concise, when it can be done Complex and Wonderful,

I follow K.I.S.S. when I can.

Okay, here goes Part 3. In this part even Yeasty gets a special mention .

I don't think I have done a great job below as I find this whole area pretty hard to explain. I wouldn't bother reading it in any detail unless you would like to use the grain bill example it contains to check or better understand the software/formulas you are studying.

[center]Extract Potential of a Grain Bill and What Can Be Calculated from It.[/center]

Above we learned that extract potential is basically the amount of 'fully fermentable' sugar in a fermentable or grain. We learned that sucrose is 100% fully fermentable and that some maltsers when expressing extract potential may write it as a percentage or in ppg or in L°/K. Furthermore some maltsters will tell you the extract potential of the grain or fermentable based on a dry weight while others may express it based on the fermentable and it's natural moisture content. Some maltsters have more obscure ways of expressing or measuring extract potential which we won't go into here.

Even ignoring the more obscure methods, we still have six possibilities to deal with. Let's have a look at a grain bill that has six fermentables from six different maltsters.

Our Example Grain Bill

Let's assume we are going to use the following grain bill in what would end up being a probably horrible beer ...

2.00 kg or 4.41 #'s Briess American 2 Row Brewers Malt - FGDB = 80.5% MC = 4.2%
1.50 kg or 3.31 #'s Gambrinus Canadian Pilsner Malt - FG?? = 80.0% MC = 5.0% (?? - Will assume DB)
0.91 kg or 2.00 #'s Weyermann German Rye Malt - FG?? = 85.0% MC = 6.0% (?? - Will assume DB)
0.23 kg or 0.50 #'s Crisp British Melanoidin Malt - ???? = 79% MC = 4.5% (???? - Will assume FGDB)
0.50 kg or 1.10 #'s Joe White Australia Bintani Organic Pilsner - FGDB = 80.0% MC = 4.5% FGAI = 76.4%
1.0 kg or 2.2 #'s Sucrose - FGAI = 100% MC = 0%

You'll see from the above that I haven't been able to find any maltster as yet that gives their extract potential in L°/K or ppg. That's a positive sign of some uniformity. You will however notice, in three cases above, question marks. These indicate where basic information is lacking. I have guessed what they mean in these cases. Another thing to remember is that many of the above specs are minimums so the actual grain may well be a few percent higher than the specs above.

Anyway, let's convert the above into a spreadsheet that shows the extract potential of the above grain bill in percent, ppg and L°/K. Section A of the attached spreadsheet shows this. [center]Now that we have the weight and FGAI of our fermentables, what can we do?[/center]

Once we have the weight and FGAI of our fermentables, we can gather some meaningful information. If you have a look at section B of the attached spreadsheet, you will see that our example grain bill at 100% efficiency would have the sucrose equivalent of 5.0 kgs or 10.9 pounds. A pound of sucrose contains 46.12 gravity points so our grain bill can potentially yield 504.8 gravity points.

[If you like Yeasyy's confusing method , the grain bill will yield 1930 (5.0 kgs * 386) litres of wort with a specific gravity of 1.001. That's as far as I'll go with L°/K .]

[center]Calculating Efficiencies - EIK, EOBE and EIF[/center]

Once we have the 504.8 number above, we can easily calculate efficiency.

Efficiency into Kettle (EIK)

For example, if we brewed the above grain bill and found that we had 35.0 litres (9.25 gallons) of wort going into the kettle with a specific gravity of 1.048, we can find our total gravity points by one of the following formulas...

Metric: Litres(Hot) * 0.9614 * 0.26417 * (Specific Gravity -1) * 1000 = 35.0 * 0.9614 * 0.26417 * (1.048 - 1) * 1000 = 426.7 gravity points

Imperial: Gallons(Hot) * 0.9614 * (Specific Gravity -1) * 1000 = 9.25 * 0.9614 * (1.048 - 1) * 1000 = 426.7 gravity points

Our Efficiency into Kettle (EIK) would therefore be 426.7 / 504.8 * 100 = 84.5% EIK

Notethat the 0.9614 adjusts our wort volume to ambient temperature.

End of Boil Efficiency (EOBE)

At the end of the brew, let's say we chilled our wort in the kettle and then found we had 26.5 L or 7.0 gallons of wort with a specific gravity of 1.060. To work out our End of Boil Efficiency (EOBE) we can use the following formulas. (Note that we can skip the 0.9614 step in this scenario as we measured the wort when it was cool).

Metric: Litres (Chilled) * 0.26417 * (Specific Gravity -1) * 1000 = 26.5 * 0.26417 * (1.060 - 1) * 1000 = 420.0 gravity points

Imperial: Gallons (Chilled) * (Specific Gravity -1) * 1000 = 7.05 * (1.060 - 1) * 1000 = 420.0 gravity points

Our End of Boil Efficiency (EOBE) would therefore be 420.0 / 504.8 * 100 = 83.2% EOBE

Notice how this is pretty close to our EIK? Theoretically they should be the same though Even though we have less volume, the 'sugar' concentration has increased so we really haven't lost any sugar. Remember, in real life, getting two EIK and EOBE measurements to agree is very rare due to measurement errors.

Efficiency into Fermentor (EIF)

Finally, let's say that when we drained our kettle into the fermentor, we ended up with 23.1 litres or 6.1 gallons in the fermentor. (In other words, we left behind 3.4 L or 0.9 Gal of trub). Because we haven't added any DME or top up water, our specific gravity should still be 1.060. Basically we just have less volume of the same gravity. For this reason, we should expect our Efficiency into Fermentor (EIF) to be lower than our EIK or EOBE. Let's see by how much...

Metric: Litres (Chilled) * 0.26417 * (Specific Gravity -1) * 1000 = 23.1 * 0.26417 * (1.060 - 1) * 1000 = 366.1 gravity points

Imperial: Gallons (Chilled) * (Specific Gravity -1) * 1000 = 6.1 * (1.060 - 1) * 1000 = 366.1 gravity points

Our End of Boil Efficiency (EOBE) would therefore be 366.1 / 504.8 * 100 = 72.5% EOBE

[center]Other Things You Can Calculate[/center]

Once you become familiar with the principles above, you can estimate gravities at different stages of the brew or work out the affects of adding top up water or DME to the fermentor.

Or, if you value your sanity, when the BIABacus comes out, you can just use that . I am never doing another calculation by hand again!!!!


PP

My goodness! That last post took me about 6 hours to write, it's been up for 36 hours and the spreadsheet contained in it has been downloaded, wait, let me count, one time!!!!



To whoever it was who waded through all the above and downloaded the spreadsheet, my apologies for a poorly structured explanation. It's the third or fourth time that myself or someone else on the BIABacus/BIABrewer team has tried to write an answer on this question (all the others have been written off-forum) and each time we've always thought our answer was generally crap or too hard to read and understand.

I haven't had time to double-check my numbers above but am assuming they are right. Poor numbers can quickly turn people off. But, one download? That definitely indicates poor writing .

On the next attempt I think we should keep things very simple and introduce the complexities later. Basically, writing the posts above in reverse order would, at least, be a start.

...

The writing team here is very small so if you find a post on anything, by any member, that you think is good, please PM BIABrewer. (Or, if you can re-arrange or make improvements to existing posts, please do the same.) The other day, we worked out that the equivalent of a large novel should be written. Writing it well is definitely going to require a community effort.

Lurkers are often great writers so hopefully some of them will help as well?


PP

PistolPatch wrote:My goodness! That last post took me about 6 hours to write, it's been up for 36 hours and the spreadsheet contained in it has been downloaded, wait, let me count, one time!!!!

That was me taking one for the team I love a good spread sheet.

PistolPatch,

You have to slow down man! "Relax and Have A Home Brew" RAHAHB! You are going to burn out! You are doing great work but it will go unfinished if you have a coronary! No one can replace you! You are the man! We all know your commitment to the BIABacus is your utmost priority but "mellow out"! (I just made up that phrase so if it doesn't make sense don't worry about it!)

PP,what BB said.
Bob,could we mellow PP out if we FWH'd him?
I like that "mellow out" phrase,it may catch on!

Yeasty wrote:

PistolPatch wrote:My goodness! That last post took me about 6 hours to write, it's been up for 36 hours and the spreadsheet contained in it has been downloaded, wait, let me count, one time!!!!

That was me taking one for the team I love a good spread sheet.

Honest it actually was me I'm determined to get my head around this topic. Like most things in brewing you find a method that works and stick with it. Trying to grasp another concept can be a right old mind fart, especially when numbers are involved. I had a look at the spreadsheet yesterday but sadly other stuff has had to take priority since.

Its all the Americans fault. Its about time they got there poop together and embraced the Metric system

Good Day, To be Offtopic or ON topic,
Check this "Grain Reference" for many SRM and Potential SG per pound of grains http://www.beersmith.com/Grains/Grains/GrainList.htm


Yeasty, in 1971 the U.S.A. set the Metric System as a "second system" of Measurement.

The Society of American Engineers (SAE) said "NO, stay with SAE system", America did.
So only US dont do KKC(Kilogram,Kilometer,Celsius). Maybe thats why we are Seppo's

Lylo wrote:PP,what BB said.
Bob,could we mellow PP out if we FWH'd him?
I like that "mellow out" phrase,it may catch on!

Mellow out is much better than "CHILLAX", Jeez i hate that one!
All in favour of FWH PP say aye

On topic though PP, i think people are at different stages of their brewing "career" and some subjects/areas etc. are not on their radar (YET).
I personally do not have an interest in that at the moment, but probably will in due course.

joshua wrote:Good Day, To be Offtopic or ON topic,
Check this "Grain Reference" for many SRM and Potential SG per pound of grains http://www.beersmith.com/Grains/Grains/GrainList.htm" onclick="window.open(this.href);return false;


Yeasty, in 1971 the U.S.A. set the Metric System as a "second system" of Measurement.

The Society of American Engineers (SAE) said "NO, stay with SAE system", America did.
So only US dont do KKC(Kilogram,Kilometer,Celsius). Maybe thats why we are Seppo's

I'm supposed to be working !! but decided to procrastinate and innoculate some slants, now I'm procrastinating my procrastination and posting on here.

This thread has gone a bit "off" topic in the fact that its gone into more detail than wbosher was probably expecting, but it has thrown up some good points for further discussion.

wbosher: Have we answered your question or have we totaly put you off even thinking about efficiency ? Sorry if its the latter

Joshua: I've seen that grain list before and probably have it saved somewhere. It wouldn't take alot to develope it further and add columns to include L°/Kg, PPKg, % and PPG uk. I think it would then be a useful reference. (unless its already out there )

[Sorry for the side-track wbosher . Hope you don't mind us using your thread to try and make things easier for the next poor bugger that asks the same question as you . Grab yourself a beer for taking one for the team .]

Bob, Lylo, Yeasty and mally. Don't mind me guys. The last six weeks have had lots of distractions - work, travel, visitors etc so am just getting a bit frustrated that I haven't been able to finish some jobs I said I would do for the BIABacus release yet.

The last thing that has to be done is structuring the forum for the BIAbacus help, terminology etc. The actual help can be written gradually after release. The help on this subject and hops will be the hardest to write and I was hoping that writing all the above would trigger a few light bulbs for the structure side. Yesterday I couldn't see that anything had been gained but today it actually triggered one light bulb so all is good.

Latest visitors leave on Sunday so maybe I can do a bit better on my jobs here then. Can't wait until they are finished as I am hanging to do heaps of mini experiments.

mally: The different stages of the brewing career thing is so true. One of the major goals of this structure is to ensure that readers can easily find the level of information suitable for their experience and level of interest. For a start, the info should be in bite sized chunks. As you can see, I certainly had a massive fail in that department here . It's always a bit disappointing when you fail to write things that are easy to understand and read. But each attempt teaches you a better way and this topic is probably the hardest one of all as so many areas have to be covered and in different units.

Yeasty: Thanks heaps for the stuff you have been sending through on the British system. It's been excellent. Hope you can have a crack at the example grain bill above in LDK and find that discrepancy I mentioned. Good on ya!!!

Oh, and just saw your post above re josh's link. We have a draft grain list behind the scenes which will get things under way for the BIABacus. It is another problem area though once again due to all the different grain names, lack of standards on grain classification and the difficulty in finding specs for many. e.g. Can't get any yield numbers on Weyermann malts. That will probably be something that can be built on later. Phew!

In the BeerSmith list, it doesn't say if they mean FGDB or FGAI anywhere in the program. When you do add a grain into BeerSmith it actually ignores whatever Moisture Content you put in so you would assume they mean FGAI but the sample grain list looks more like Dry Basis to me. Go figure

Bugger, that was meant to be a really short post .

Hooray, it's finally Friday afternoon. Thanks a heap and have a great weekend guys .

[wbosher: Re your question of doing efficiency calcs by hand, they are very easy to do, on the surface. The following, if you want to wade through it, explains why any simple answer you get won't work for all brewers in most situations.]

Yeasty and I were able to get all the maths sorted on extract potential over the weekend and everything agrees perfectly now .

Here's some conclusions...

[center]Why has this thread been so complicated?[/center]

The problem here has been that BIABrewer is an international website so, any answer really needs to make sense for everyone. Efficiency calculations aren't really that complicated if you are dealing in one measurement unit (UK, US or Metric).

Existing explanations or articles on efficiency calcs all start from a premise that the reader will be basing their calcs from one point of view (UK, US or Metric).

Providing a US, UK or Metric answer (and then converting it to other units) is easy and it's great for a basic understanding of efficiency calcs but they are not a practical reality as any brewer, in any country, often uses foreign grains with foreign specs.

The practical reality is the problem we have been trying to deal with here.

The Main Units - Four Basic Layers (and a fifth more obscure one)

Efficiency calculations are actually only based on only two things, volume and weight. That's it! Let's have a look at how quickly though these two units become complicated...

If we regard volume and gravity as being the first layer then already we have five units to deal with. Volume can be given as litres, UK gallons or US gallons whilst weight can be given in kilograms or pounds. (We won't consider mls, pints, grams, ounces etc here.)

The second layer is specific gravity which is a simple ratio of weight versus volume, hence the terms, 'degrees' or 'points'. However when we convert it to points per pound per US gallon (ppg US), points per pound per UK gallon (ppg UK), or litres per degrees (points) per kilogram, you'll have to grab a beer to wrap your head around the differences.

The third layer of complexity comes in when we look at the specific gravity of sucrose as this is our 'extract potential' reference point. This can be expressed as ppg US, ppg UK, LDK or as a percentage.

The fourth layer is Moisture Content. This means that anything in the third layer can be expressed as having allowed for moisture or not.

The fifth, very obscure layer, is the laboratory method used to determine extract potential. Some of these are basically fine grind, coarse grind, hot water and cold water extract.

That's why it is so complicated!

[center]Making it Simple[/center]

Once again, everything boils down to clear terminology and definitions so as everyone has a common language to work from.

No one can work out their efficiencies (EIK, EOBE, or EIF) by hand, confidently, on a grain bill without understanding extract potential and, hopefully, you have seen how hard that is. In other words...

Unless you understand extract potential well, any figures you use in your calcs could well be wrong. (The real truth is that you would be hard pressed getting any accurate specs on the grains you use.)

Earlier this year, the BIABacus team, looked at this whole extract potential thing in great detail and concluded that the common ground to express extract potential should be as a percent or specific gravity on a FGAI basis and only allow two inputs - FGDB and MC.

We've racked our brains on this over and over and, if you start from this premise, everything becomes at least, somewhat, possible to explain.

I think once we have the BIABAcus out there, it will provide a backbone so as questions like this can be answered well at whatever level of detail the reader needs. Answering efficiency questions without a backbone and clear terminology to work from is pretty messy and frustrating.

Atm, it's a bit like putting IKEA furniture together without the tools. At least, if you have the tools, it's only going to take a day or so to understand the instructions.

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PP

Good Post PP, except "However when we convert it to points per pound per US gallon (ppg US), points per pound per US gallon (ppg US), or litres per degrees (points) per kilogram, you'll have to grab a beer to wrap your head around the differences." Should there have been PPG UK???

I question, I have always have had is, America and UK have Points/Pound, Metric does not have Points/Kilogram.

If they did, the Points/Kilogram/Liter would be VERY easy to work with!!!