[Homebrew_kev]

I've had my own mill now for a year. It's worked fine, but I'm interested in learning more about how crushing grains can improve efficiency. I generally just crush a hand full and if it looks crushed enough, i just finish it off.

Are there any measurements I can take? How can I get more out of the grain?

[denny]

You're gonna get all kinds of technical answers, but I'll tell you crush is dependent in your system and how YOU brew.  I think you're doing exactly the right thing.  I'd recommend you experiment with a little more crush or a little less crush to see the difference for yourself.  That's exactly what I did and it's worked great for me.  I found a crush that works for me and my system.

[Slowbrew]

My approach when I got my first mill was to use it at the factory default for a few batches.

Then when I had the process figured out I started tightening the gap on my mill a little each brew until I started having problems.  Stuck sparges and that type of thing. 

The finer my mash, the higher my yield was.  The trade off was trouble sparging and the extra time caused by things getting gummed up.  I found the spot my system worked and left it there.

Paul

[BrewBama]

Set the gap and brew with the crushed grain. If you don’t get stuck tighten the gap and brew with the crushed grain. Repeat until you get a stuck mash then go back to the last gap that produced a mash where you didn’t get stuck. 

Three thoughts:
1) Measure the gap in the same place each time you adjust.
2) Perform everything else as you normally would (e.g. if you stir at 20 min or something do it the same every time, same water volume, same pump setting, same everything except the gap).
3) Use the same amount of grain for this series of brews.

It’s a tedious process but it’s likely the only way you’ll know how much you can crush the grain to the point of a stuck mash on your system.  Your system may allow a very fine flour. Mine won’t tolerate flour so I use more grits than flour.

An alternative to measuring the gap is to measure a set amount of grain on a standard sieve.  Using a standard shake protocol, measure what stays on the screen vs falls thru. I shoot for 70% remaining on a No 14 sieve. There’s a match mark Mr JSP etched onto my mill and adjustment knob. I know that the right edge of the mark on the knob aligned with the left edge of the mark on the mill is my go-to setting.


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[ynotbrusum]

Good old Jack Schmidling - his mill is still going strong for me after many years.  My sweet spot is .040" and if I am not recirculating, I stir 3 times during the mash (start, midpoint and 5-10 minutes from the end of the mash).  Just got there by trial and error, as with others here.

[Semper Sitientem]

I didn’t see it referenced and maybe it’s a given, but in regards to measurements, are you using a feeler gauge?

[denny]

Good old Jack Schmidling - his mill is still going strong for me after many years.  My sweet spot is .040" and if I am not recirculating, I stir 3 times during the mash (start, midpoint and 5-10 minutes from the end of the mash).  Just got there by trial and error, as with others here.

Yep.  20 years and tons of grain on mine

[KellerBrauer]

I didn’t see it referenced and maybe it’s a given, but in regards to measurements, are you using a feeler gauge?

Yes.  In addition to the excellent advice offered by the other brewers, i recommend using the feeler gauge on each end of the adjustable roller. 

Referring to my mill, a Barley Crusher, i have an adjustment screw on each end of the adjustable roller.  I use a feeler gauge to adjust each end so they are "perfectly" parallel and equal.  I used quotation marks because the idea is to get it as close as possible.

I started with factory and kept closing my gap until i had trouble with the sparge, than i opened it .002" as i recall and found the sweet spot.  Took me about 6 brews to get it right.

[Homebrew_kev]

I didn’t see it referenced and maybe it’s a given, but in regards to measurements, are you using a feeler gauge?

No I don't use a feeler gauge. That's why I was asking, I just eye ball measurements. I pretty much eye ball everything when I brew - if i ever open up a brewery i should call it Eye Ball Brewing

[BrewBama]

... i recommend using the feeler gauge on each end of the adjustable roller. 
..

The JSP is adjustable only on one end so it’s actually wider at one end than the other. That’s why I recommended measuring in the same place every time.


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[Semper Sitientem]

I didn’t see it referenced and maybe it’s a given, but in regards to measurements, are you using a feeler gauge?

No I don't use a feeler gauge. That's why I was asking, I just eye ball measurements. I pretty much eye ball everything when I brew - if i ever open up a brewery i should call it Eye Ball Brewing

IMO, It’s a very cheap, important tool if you’re milling your own grain.

[narvin]

I'm a fan of the feeler gauge, if you have an adjustable mill, because repeatability is important for you to be able to learn what works and what doesn't.

That being said, everything else is going to depend on a lot of factors.  BIAB and batch sparging are going to be more forgiving.  If you're recirculating with a false bottom, too fine a crush can result in compaction or channeling, and too coarse poor extraction.  It all depends on your system.

[erockrph]

Since my feeler gauges all have machine oil on them,  I prefer not to use them in my grain mill. I use guitar picks instead. I always have a bunch all over the place, so it's an easy reference for me. The gap that works for me is a 0.88mm (Dunlop tortex green) pick.

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[KellerBrauer]

... i recommend using the feeler gauge on each end of the adjustable roller. 
..

The JSP is adjustable only on one end so it’s actually wider at one end than the other. That’s why I recommended measuring in the same place every time.


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That’s interesting.  I’m not familiar with a JSP.  However, I have read that some suggest creating a tapered gap — even with rollers that are adjustable on both ends.  It is supposed to deliver efficiency and ease sparging.

[jeffy]

... i recommend using the feeler gauge on each end of the adjustable roller. 
..

The JSP is adjustable only on one end so it’s actually wider at one end than the other. That’s why I recommended measuring in the same place every time.


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That’s interesting.  I’m not familiar with a JSP.  However, I have read that some suggest creating a tapered gap — even with rollers that are adjustable on both ends.  It is supposed to deliver efficiency and ease sparging.

Except that with a JSP it all gets funneled into the center.