"Understanding Efficiency" on Braukaiser

I've been using the table under "Conversion Efficiency" to determine if I got full conversion, and have abandoned the iodine test.

Here's the link: http://www.braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Conversion_efficiency

I was trying to find a way to use Beersmith in order to get a more accurate value based on the grain bill without assuming the 80% fine grind extract and 4% moisture content.

So I input 100% mash efficiency, zeroed all the losses, and entered batch volume 30l and 10kg of pilsner malt. Modified the pilsner ingredient sheet so it said 80% yield and 4% moisture content.

This is 3l/kg or 1.44qt/lb and according to the table it should provide 1.085 wort. Beersmith says 1.102 though.

What am I missing?

Subbed, because I'd like to know the answer too. Inspired by that same article I started monitoring my conversion efficiency too. I have Beersmith, but just do the 100% efficiency calculation in my own spreadsheet - it's just simple PPG math. When I run your numbers I also get about 1.102. So I'm not sure why it doesn't match the table. The table is correct per the equations he lists, but I don't totally follow the equations.

Raisoshi said:

So I input 100% mash efficiency, zeroed all the losses, and entered batch volume 30l and 10kg of pilsner malt. Modified the pilsner ingredient sheet so it said 80% yield and 4% moisture content.

This is 3l/kg or 1.44qt/lb and according to the table it should provide 1.085 wort. Beersmith says 1.102 though.

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If you take 10 kg of malt that has 4% moisture then you have 9.6 kg on dry basis. Assuming that the yield is 80% (typical lab yield number fine grind) you have 0.8*9.6 = 7.68 kg potential extract. Adding 30 L water to that (which, note, is not the same as a final batch volume of 30L so that may be the problem) would give a wort strength of 100*7.68/(7.68 + 30) = 20.38 °P if all the potential extract were realized. 20.38 °P corresponds to apparent SG (20/20) of 1.08467. Looks like the same answer as in the table. I don't see how the gravity can be higher than this, in fact it would doubtless be lower as most home brewers achieve appreciably less efficiency than the fine grind laboratory value. I can only assume that Beersmith is using less than 3L/kg as the strike water volume is typically less than the batch size.

I could be wrong, but I believe the discrepancy is because you're talking about batch volume and the table uses strike volume.

Also, Braukaiser used a grain absorption of 1 L/kg. This means that for your 10 kg, 30 L strike water, 80 % FG/DB, 4 % moisture, while the mash efficiency is 100 %, the efficiency into the kettle (without a sparge) would be only 58 %.

When you set 0 losses and input 100% Tot Efficiency in beersmith, shouldn't that mean you've extracted any liquid that is inside the grain?

I mean, if Tot Efficiency = Mash Efficiency + Lauter Efficiency, isn't 100% Tot Efficiency the same as full conversion + lautering ALL the wort out of the grains?

In this case it should equate to 30l of water in 10kg of grain ending up as a 30l batch size(boil is set to 0min). Maybe they use different equations? Or beersmith doesn't do well with 100%?

Ah, yes. I think that's correct. But somehow they come up with a gravity that implies greater than 80% extraction and that just doesn't happen in the real world. Sometimes you will see 81 or 82% for a Congress mash but I don't recall ever seeing higher than that.

ajdelange said:

Ah, yes. I think that's correct. But somehow they come up with a gravity that implies greater than 80% extraction and that just doesn't happen in the real world. Sometimes you will see 81 or 82% for a Congress mash but I don't recall ever seeing higher than that.

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I guess I just can't use Beersmith for that then, I've tried changing numbers but can never get 1.085 in a way that would make sense... funny thing: if you input 50% moisture, the SG doesn't change at all.

I'll just make a spreadsheet and input the grain bill and their info by hand.

Raisoshi said:

... funny thing: if you input 50% moisture, the SG doesn't change at all.

Click to expand...

That shakes my confidence in it.

Raisoshi said:

I'll just make a spreadsheet and input the grain bill and their info by hand.

Click to expand...

I always trust my own spreadsheets more than other peoples' and it's easy enough to do. The only thing you might not have is the Plato to SG conversion. You have to do it by inverting the ASBC SG to Plato formula which is

°P = -616.868 + 1111.14*SG - 630.272*SG*SG + 135.997*SG*SG*SG

Designate a cell for SG and put the formula in another cell. Then put 1 in the SG cell and ask the Solver to set the °P cell to the value of °P you wish to convert by varying the SG cell. Or you can solve the equation above in closed form for SG. It is messy algebraically but readily doable.

I had a very similar problem recently, I believe the answer is the same in your case.
https://www.homebrewtalk.com/showthread.php?t=540961

Contrarian said:

I had a very similar problem recently, I believe the answer is the same in your case.
https://www.homebrewtalk.com/showthread.php?t=540961

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Thanks for the info. I had a suspicion this is the explanation for the difference, but it's surprising to me that sugars would take up that much volume.

ajdelange said:

That shakes my confidence in it.

I always trust my own spreadsheets more than other peoples' and it's easy enough to do. The only thing you might not have is the Plato to SG conversion. You have to do it by inverting the ASBC SG to Plato formula which is

°P = -616.868 + 1111.14*SG - 630.272*SG*SG + 135.997*SG*SG*SG

Designate a cell for SG and put the formula in another cell. Then put 1 in the SG cell and ask the Solver to set the °P cell to the value of °P you wish to convert by varying the SG cell. Or you can solve the equation above in closed form for SG. It is messy algebraically but readily doable.

Click to expand...

@ajdelange

I have seen the above cubic for SG to plato and also the following polynomial for plato to SG:They are not inverses of each other. Which is considered to be more correct?

Brew on