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.

**Extract Potential of a Grain Bill and What Can Be Calculated from It.**

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.

Extract Potential Example.xlsx

**Now that we have the weight and FGAI of our fermentables, what can we do?**

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

.]

**Calculating Efficiencies - EIK, EOBE and EIF**

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

**Note**that 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

**Other Things You Can Calculate**

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

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