BIAB Efficiency Calculation

[VikeMan]

I guess maybe that’s my hang up. I could never achieve 100% because I would never finely grind my malt or squeeze extract from my mash tun liner.

I believe @doug293cz speaks of 100% efficiency only in the context of conversion of starches to non-starches (his conversion efficiency, your first wort efficiency). So squeezing (or not) doesn't enter into it at that point.

 

[Big Monk]

My point is don't let chasing numbers distract you from what is important. A beer that tastes good is good.

Right. It’s really extract quality that matters, not quantity.

 

[Big Monk]

I believe @doug293cz speaks of 100% efficiency only in the context of conversion of starches to non-starches (his conversion efficiency, your first wort efficiency). So squeezing (or not) doesn't enter into it at that point.

True. I misspoke there.

More to the point: I can’t bring myself to finely grind my grist, especially because of my constant recirculating preference. Not to mention other mash related factors. So, 100% “whatever you want to call it” efficiency is not in the cards for me.

 

[VikeMan]

My point is don't let chasing numbers distract you from what is important. A beer that tastes good is good.

I couldn't agree more, if by chasing numbers you mean shooting for higher and higher efficiency, rather than reasonably accurately predicting gravities and volumes using a dialed-in process.

 

[VikeMan]

I can’t bring myself to finely grind my first, especially because of my constant recirculating preference. Not to mention other mash related factors. So, 100% “whatever you want to call it” efficiency is not in the cards for me.

Personally, I believe (can't really prove, obviously) that I get a cleaner malt flavor from a moderate crush than a super-fine crush. Plus, I don't do BIAB, so an all flour grist wouldn't work for me anyway.

 

[doug293cz]

I guess maybe that’s my hang up. I could never achieve 100% because I would never finely grind my malt or squeeze extract from my mash tun liner. (EDIT: see Vikeman’s response below to explain strikethroughs)

In this case it seems it’s just methods outside my SOP, i.e. I’d rather stick with lower efficiency and keep a coarser crush/not squeeze. The ends don’t justify the means IMHO.

Glad we cleared that up!

Nothing wrong with that. Life is a series of compromises in just about every aspect. Everyone must make their own compromises based on the criteria that are more or less important to them. Efficiency for efficiency's sake only makes sense for large scale commercial brewing. For homebrewing, having a consistent (and therefore predictable) process is much more important (for most brewers.)

The writing I do about efficiency is primarily to help brewers understand what affects efficiency, how to rigorously calculate it (if interested), and assist brewers in diagnosing exceptionally low efficiency.

Brew on

 

[Big Monk]

Nothing wrong with that. Life is a series of compromises in just about every aspect. Everyone must make their own compromises based on the criteria that are more or less important to them. Efficiency for efficiency's sake only makes sense for large scale commercial brewing. For homebrewing, having a consistent (and therefore predictable) process is much more important (for most brewers.)

The writing I do about efficiency is primarily to help brewers understand what affects efficiency, how to rigorously calculate it (if interested), and assist brewers in diagnosing exceptionally low efficiency.

Brew on

I agree. It’s much of what I try to help with also. Troubleshooting pH and efficiency are my side hobbies.

 

[HBearBrew]

This chart shows the highest possible lauter efficiencies (and thus the highest possible mash efficiencies) available for a couple of different grain absorption rates, and four different counts of batch sparge steps (including none.) Since mash efficiency equals conversion efficiency times lauter efficiency, mash efficiency will always be less than or equal to lauter efficiency. You should target as close to 100% conversion efficiency as you can (you appear to be there already with your first BIAB.)

View attachment 697568

Brew on

Thanks @doug293cz for this very helpful chart. Your explanations, together with this article (Declining Extract Efficiency at Higher Original Gravities) and the corresponding chart (extract efficiency) helped me finally understand why my efficiency varies, and how to accurately plot it. I have read Kai's webpages, and went back to John Palmer's chap 19. It has a very useful table for BIAB expected extract efficiency.

I do BIAB no sparge - not the most efficient approach of course, but quite predictable at the end and that's good enough for me

Based on all these readings, I was able to put together a quick calculator for expected efficiency, see the excel table in the compressed file attached. It is based on one's system, so you need to write down in the table the water to grist ratio and efficiency of several batches for the calculator to be able to plot the expected efficiency. I used kg and l in my example, but it can be as easily used with pounds and gallons, as long as one is consistent with the unit used.

Thanks for the inspiration