# Dang, I'm Good: 103% Conversion....

Discussion in 'Recipe Editor' started by Nosybear, Jun 16, 2020.

1. ### Nosybear Well-Known Member

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#1
I've wondered about the new conversion calculations requiring the total volume of water used, so I went with it on this recipe. The following was the result:

Here's a close-up of that efficiency:

It was a mutt brew so I wasn't really careful with my volumes. Here's a link to the recipe:

https://www.brewersfriend.com/homebrew/recipe/view/1010854/speltweizen/343184

There is no sugar or anything else that should have punched the efficiency above 100%. So there's something I'm not getting about how the efficiency is calculated. As mentioned above, I've questioned it for some time. Now I have an impossible result. My only hypothesis is it's using the rice hulls as convertable grain weight.

2. ### Trialben Well-Known Member

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#2
Every brew day my conversion efficiency is above 100% around that 103-106%
I ignore it but take note on my preboil I find this will more closely resemble what I'll get percentage wise into the fermentor.

3. ### BrewPatgonia Well-Known Member

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#3
looks like I'll have to try the 'kesselmaische' method to get my efficiency through the roof.

4. ### Yooper Administrator Staff Member

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#4
To get a more accurate conversion efficiency estimate, entering the volume is critical.

Also, make sure the malt specs in the chosen brand/type of malt are exact. Some vary from batch to batch.

5. ### Nosybear Well-Known Member

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#5
I did. I used 6.9 gal. total mash and sparge water. Check to see that the rice hulls aren't somehow included in the calculation. I didn't enter the exact brand of malt but any result above 95% is suspect.

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6. ### Trialben Well-Known Member

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#6
Gee you loose a bit in the kettle there noseybear. Must have a bit of dead space going on?

7. ### Nosybear Well-Known Member

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#7
I wasn't being careful.

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8. ### Herm_brews Well-Known Member

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#8
I got a conversion efficiency of 97% on my brew yesterday, while being 3 points below the recipe estimated pre-boil gravity. In the end, I was right on my Original Gravity and volume to fermenter, ending with 79% brew house efficiency.

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9. ### Trialben Well-Known Member

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#9
This is usually par for the course for me.

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10. ### Yooper Administrator Staff Member

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#10
11. ### Pricelessbrewing QA Software Tester Staff Member

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#11
Will do. I saw the thread yesterday but knew it was going to take more than a spare couple minutes to review.

I'll be working all this afternoon and will make sure to followup.

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12. ### Nosybear Well-Known Member

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#12
Somehow the math isn't working. About 90% should be the conversion efficiency for homebrew. What we're getting seems to be averaging on 100% - none of us are doing Congress mashes!

13. ### Yooper Administrator Staff Member

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#13
My last batch seems about right:

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14. ### Nosybear Well-Known Member

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#14
That's about what I would expect. I'm entering the total water in the "Mash Complete" step - mash plus sparge. For the recipe I started with, that was 6.9 gallons. I got an OG of 1.039, 269.1 points. My grain bill was 7.5 pounds excluding the rice hulls. That approximates to 270 points at theoretical maximum. I'd still be hitting 99% with that back-of-the-envelope calculation. So perhaps I measured wrong - I ended up with far fewer points in the wort after the boil, 204.78. That gives 75%, closely matching what the software gave for pre-boil. So I'm assuming I don't understand one or more of the "Mash complete" inputs

15. ### Nosybear Well-Known Member

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#15
Working backward from what was in my kettle, I get a conversion efficiency of around 93%. Looks as if I might have measured my gravity a bit high (or misread the refractometer). That's possible.

16. ### Pricelessbrewing QA Software Tester Staff Member

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#16
I'll have a couple replies in succession here, so just bear with me.

Retesting the calculation, it seems to be working as expected.

https://www.brewersfriend.com/homebrew/recipe/view/1012326/testing-efficiency

Test recipe, simple, 12 lbs of 2 row at 70% brewhouse efficiency. This is 12lbs * 37ppg = 444 total potential points
Mash volume is 5.25 gallons (when heated to strike temp it will be ~5.38 gallons).
I expect a MASH gravity of around 1.0709 SG. At 95% expected conversion efficiency, which you noted above typical values are 92-95%.

If I enter that info into the brew session I get 94.9% conversion efficiency. Probably some rounding error somewhere, not a big deal.

An interesting tangent that I discovered a couple years ago is that from this info you can calculate the apparent WORT volume using the mash infusion volumes, and the mash gravity. Between the 5.25 gallons of water that was added, an additional 0.734 gallons of wort volume was created due to the dissolving sugars/starches/proteins. Thjis wort volume can be used to track efficiency through the entire system similar to total gravity points.

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17. ### Pricelessbrewing QA Software Tester Staff Member

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#17
Last edited: Jun 18, 2020
I already have a ticket to clarify the tooltip in the brew session, and update the documentation so that it matches.

For conversion efficiency you must enter all mash infusions, strike/infusions, but not sparges, and the gravity reading again must be taken prior to any sparges. This could be literally inside the mash, or it could be the runoff from the mash prior to sparging. Either should be the same. Stirring to ensure homogeneous gravity is highly recommended.

Any efficiency calculation is only as accurate as your volume and grain bill. If you're eyeballing it, and are off by a quarter gallon, well that corresponds to a 10% difference in volume and is the difference between getting 101% instead of 92% conversion. If your grain bill information is off, either in measured weight of each grain, or the PPG, then that also introduces an error bar. If your base malt is 36 ppg instead of 37 ppg that makes a difference as well.

It looks like @Nosybear and @Trialben you're both entering preboil gravities instead of mash gravities, prior to sparging, and are including the sparge volume in the mash complete volume log.

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18. ### Pricelessbrewing QA Software Tester Staff Member

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#18
@Nosybear

I'm not sure if you took a first runnings or mash SG sample or not, so I can't be entirely certain. I'm also having some difficulty understanding your volumes. 7 gallons seems like quite a lot for the batch size, and doesn't match your equipment profile which would dictate 6.11 gallons instead. So I can't do any backwards calculations on what I would normally expect following a decent sparge.

19. ### Mark Farrall Well-Known Member

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#19
Is there some assumption of there being a sparge? I'll get the odd low 100% conversion reading and I'm nearly always doing full volume mashes. I know Ben also mashes pretty thin.

20. ### Nosybear Well-Known Member

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#20
I never have taken first running readings and suspected something like this might be the problem. I guess I can start, just so I have the statistics on my brews. I also suspected I might need to in order to use the function. Hopefully the tool tips will be clearer. So let me see if I have this:

Enter all MASH ONLY liquor for the volume.
Enter the FIRST RUNNINGS ONLY gravity for the gravity.
The system will calculate sugars left in the mash tun using the grain absorption and dead space.

Devil's advocate question: What if we add simple sugars to the mash? Does the system know enough to compensate for that? Or if we, as some have done, mash in with maple sap?

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