Inconsistent mash efficiency calculations

[reuliss]

Sorry if moderators feel that this is the wrong forum, but I keep getting different efficiency calculations from two different sources and I'm curious if anyone can shed some light on why. When I pump in my preboil gravity and volume into iBrewmaster, I get 80% efficiency. If I pump those same numbers into brewers friend (http://www.brewersfriend.com/brewhouse-efficiency/), I get 73% efficiency. What gives?

For what it's worth, I really want to have the lowered efficiency. I have been battling some nasty astringency issues. If anyone is curious of my numbers here they are:

Gravity 1.050
Volume (preboil): 8.9

Grain is is as follows

13.5 lbs 2 row
1 lb german light munich
1lb Victory
1 lb carastan.

Any thoughts?


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[Omahawk]

Efficiency is really more about your process than recipe. Not sure that brewing software will predict it accurately. What's your mash and sparge process?

 

[reuliss]

It's not the prediction that's wrong. It's the programs' calculation of efficiency based on my actual numbers.

I provided the ingredients because Brewers friend asked for them. And as far as I understand it different grains have different extraction potential


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[Omahawk]

So you're interested in the potential yields of the individual malts? That varies by malt and maltster. I'm guessing each program has different default inputs by malt type.

 

[hannibalmdq]

The difference in efficiency is probably just from the two programs using slightly different PPG four the listed grains. The programs use various sources to estimate an average PPG for a given malt. The truth is that the PPG for your specific grain is dependent on the maltser and the individual batch of malt. Things are pretty standard but really it's all an educated estimate anyway.

You shouldn't be getting astrigency at either of those two estimates though. I agree with the above poster that it's probably something else. Mash temps, spare temps, spare rate (if not batch sparging) water chemistry. etc etc.

 

[Omahawk]

Yes, in terms of the astringency taste, that's often due to mashing at too high of a temp or over sparging.

 

[reuliss]

Those are lower numbers based on a coaster crush after I recently adjusted my mill. IBrewmaster was telling me I had 90-95 % efficiency when I had the astringency issues.

I agree they may have different assumptions, but there's a 10% efficiency difference between the two. Seems hard to explain the difference that way.


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[reuliss]

Also, I adjust my mash and sparge ph to be at 5.5. I batch sparge with water no hotter than 170.


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[Omahawk]

How long do you mash and sparge for? Whats your typical mash temp? 90-95% efficiency compared to potential yield is crazy high for batch sparging. Perhaps you're at too fine a grind?

 

[Omahawk]

And my 90-95% question assumes that the lower end of the software estimates is correct for potential yield.

 

[reuliss]

But that's my point. I don't think I really got 95%. It's just what iBrewmaster told me. Other programs tell me 85%. That is still higher than I wanted, which is why I adjusted my mill.


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[reuliss]

Also, I mash for 60 min and recirculate the sparge for 5-10 min.


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[Omahawk]

I just plugged your recipe into BeerSmith. It thinks that your recipe with 8.9 preboil volume, 7.8 gallons postboil is only 65% efficiency if it comes out 1.050.

 

[reuliss]

Wow. That's crazy. This has me completely confused. The the one at brewers friend, and you'll see it predicts much higher than that (though not as high as iBrewmaster).


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[Omahawk]

In summary: Everything you're doing seems reasonable. The calcs are fracked.

 

[reuliss]

Ha! Thank you.


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[Omahawk]

This is what I got. Make sure I didn't screw up any inputs. FWIW, sounds like a great malt profile.



Type: All Grain
Date: 6/29/2014
Batch Size: 7.80 gal
Boil Size: 8.93 gal
Boil Time: 60 min
Brewhouse Efficiency: 65.00

Ingredients

Amount Item Type % or IBU
13.50 lb Pale Malt (2 Row) US (2.0 SRM) Grain 81.82 %
1.00 lb Carastan (30.0 SRM) Grain 6.06 %
1.00 lb Munich Malt (9.0 SRM) Grain 6.06 %
1.00 lb Victory Malt (25.0 SRM) Grain 6.06 %


Est Original Gravity: 1.050 SG
Est Final Gravity: 1.013 SG
Estimated Alcohol by Vol: 4.78 %
Est Color: 8.0 SRM Color: Color

 

[reuliss]

Thank you. It's for my pale ale. Also, I think I see why beer smith came differently. 1.050 is my preboil gravity. In any event, I think our conclusion stands. Thanks for chatting!


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[Omahawk]

1.050 is my preboil gravity.

75% efficiency then. Good luck getting rid of the astringency!

 

[briggssteel]

For what it's worth I use the brewersfriend.com brewhouse efficiency calculator. It usually tells me I get around 72-75% efficiency. When I build my recipe I use the brewer's friend recipe builder and plug in 73 or 74% efficiency. My last couple of batches I've been within a couple of points of my estimated original gravity. I also batch sparge like you.

So I guess my point is that maybe brewer's friend is wrong on efficiency (I'd like to think it's right), but if you use their recipe builder it will give the same ppg for each grain as the brewhouse efficiency calculator. Therefore if you use brewer's friend brewhouse efficiency calculator, use their recipe builder because the ppg values will be the same. If you use brew smith to get your efficiency, then use their recipe builder. I think the key is more about getting consistency in your efficiency so you're getting the OG you want.

I doubt you're getting an efficiency over 85% with batch sparging unless the grain crush is way too fine.

 

[hannibalmdq]

Maybe check your thermometer? I've had two go out of wack on me in the last few months.