92% efficiency?!?

[beerisyummy]

The Brewers Friend efficiency calculator told me I got 32.6 PPG and 92% extraction efficiency! I entered all the malts, which consisted of 10 lbs Viking Pale, 2 lbs Canada Malting Malted Oats, and a smattering of other things, 14.5 lbs total. I entered the total water used as 5.5 gal. for the mash (BIAB) and 2 for the dunk-sparge, total of 7.5 gal. Pre-boil gravity, prior to top-up, was 1.063, temperature-corrected.
Is such a thing even possible? Where could I have made a mistake?

 

[VikeMan]

92% mash efficiency is possible.

But what was your measured pre-boil wort volume in the kettle? You can't calculate calculate mash efficiency without knowing that. (And neither can Brewers Friend.)

ETA: Looking at your numbers on the back of an envelope... it looks like maybe you told the calculator that you had 7.5 gallons of pre-boil wort. But you couldn't have...some of your total water used was absorbed by the grains.

 

[dmtaylor]

Yes it's possible. I've achieved 92-94% efficiency many times. In fact I just got 94% on my last batch. It is possible with a really good crush, sparging and collection of all wort to the last drop, and as VikeMan alludes, accurate measurements, especially volume, but also weight, SG, temperature, etc. If any of your measurements aren't accurate, and you feel like you bumped into this result by luck alone, then it might not be true. I'm a calibration nerd so yeah I can actually get 94% as far as I can tell. But if your volume measurements especially are off by just a quart or two, you can have drastically different results, might actually only have a more reasonable 80-85% efficiency or whatever, which is very common and still pretty darn good. If you can duplicate this result in subsequent batches, then you'll know it's real. If you can't, then you'll know you screwed up a measurement someplace.

 

[VikeMan]

If you can duplicate this result in subsequent batches, then you'll know it's real. If you can't, then you'll know you screwed up a measurement someplace.

Looking at the numbers, I suspect it's not even a measurement issue, per se. Ballpark, it looks like the total water volume was plugged in as the pre-boil wort volume.

14.5 lbs x 36 PPG x 92% / 7.5 gallons = 64
Pre-boil OG was 1.063.

 

[beerisyummy]

92% mash efficiency is possible.

But what was your measured pre-boil wort volume in the kettle? You can't calculate calculate mash efficiency without knowing that. (And neither can Brewers Friend.)

ETA: Looking at your numbers on the back of an envelope... it looks like maybe you told the calculator that you had 7.5 gallons of pre-boil wort. But you couldn't have...some of your total water used was absorbed by the grains.

Ohhhh kayyyy. So, when I put in the 6 gallons for "water used," I get 73.66% efficiency which, if disappointing, is a lot more believable. If this is the veritas here, then it seems to me the BF calculator ought to ask how much water went into the boil kettle, not how much you "used." I know it says not to count grain absorption, but it really is not semantically clear. (Mom was an English teacher, and I am now brandishing the proverbial Red Pen.)
Does that sound right?

 

[VikeMan]

Does that sound right?

I'm not familiar with brewers friend, but yes that sounds right. Any calculator needs to know the kettle volume to work.

ETA: I just took a look at Brewers Friend, and this is the calculator that would apply:
https://www.brewersfriend.com/brewhouse-efficiency/Select "pre-boil," not "conversion"

 

[beerisyummy]

ETA: I just took a look at Brewers Friend, and this is the calculator that would apply:
https://www.brewersfriend.com/brewhouse-efficiency/Select "pre-boil," not "conversion"

OH! I have been using "conversion." Well then. Thanks, VikeMan!