[Joe_Beer]

I decided to buy my own mill last week. I adjusted the rollers to a .040" gap to start with and ran a small handful of 2-row through it. Think I should I tighten it up more? No idea what an optimal crush looks like (@dmtaylor helpfully mentioned .025-.030 in another thread but not quite there yet) and not sure how and if the gap matters between different mills/rollers/knurls. pic is here: https://imgur.com/a/JBsumxS .

[Drewch]

What mash setup are you using?

I do BIAB and grind my grain basically into coarse flour, but it'd probably be impossible to lauter/sparge.

[Bob357]

The ideal crush depends your system and process. When I batch sparged and used a bazooka screen or braid, .037" worked well for me. When I used a brew bag, .025", and now, with the Digamash (all in one), I found .042" gives me a happy medium between efficiency and good flow for recirculation. Most of the more popular 2 roller mills will produce similar results with the same gaps, so using these gaps as starting points should produce reasonable results. Like anything else in your process, if you're not satisfied with the results, adjust a little at a time until you find your sweet spot.

Hard to tell from the pic, but the crush looks reasonable. I like to see a little bit of flour though. You might try a batch at your current gap and go from there.

[dmtaylor]

It's hard to tell from pictures alone but your crush doesn't look bad at all.  I've seen far worse.  You can try it there, or tighten just a few hairs more to be sure.  You should have around 10-15% fine flour, with the other 85-90% of the kernels each broken into about 5-6 chunks each.  And you should have zero kernels that are still unbroken or only broken in half, that wouldn't be good enough.  If your crush is consistent with these percentages, you are in good shape.  From here on out it will just be fine-tuning.

Cheers!

[Joe_Beer]

What mash setup are you using?

I do BIAB and grind my grain basically into coarse flour, but it'd probably be impossible to lauter/sparge.

I'm using the foundry with a bag and usually a handful of rice hulls and then recirculate with the pump. My last batch was a no-sparge which I like so I'll keep the coarse flour setting in mind.

Hard to tell from the pic, but the crush looks reasonable. I like to see a little bit of flour though. You might try a batch at your current gap and go from there.

Yeah, the pictures aren't ideal so appreciate the imagination you all are putting into this. What happens if I'm too far in the "coarse flour" grind? Does efficiency just go up while risking a stuck mash? Maybe just add more rice hulls?

You should have around 10-15% fine flour, with the other 85-90% of the kernels each broken into about 5-6 chunks each.  And you should have zero kernels that are still unbroken or only broken in half, that wouldn't be good enough. 

Thanks again! I'll take a closer look later this evening any maybe tighten the gap a little more if it seems lean on the flour.

[kramerog]

Bear in mind that grain crush varies depending on what grain you crush. I believe that the premium European malts have the smallest kernels removed while the cheapest US 2-row still has them so the spacing has to be tighter for US 2-row.  In practice I set the spacing so that I get every kernel of US 2-row is crushed and leave it there for all malts. 

[BrewBama]

If your adjuster doesn’t have marks on it (like mine), you’ll want to mark it with some sort of indication of what that setting is. Brew with that setting and see how you like it (lauter, efficiency, etc). If you tighten, remark with an indication of what that new setting is, brew, rinse, repeat.

If you’re using all malt barley you don’t need rice hulls. Your barley husks do the filtering for you. The rice hulls just suck up water. Now, if you’re using a lot of huskless grains you might consider rice hulls. I recommend soaking them before adding them to the mash.


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[denny]

Doesn't matter how it looks or what your gap is. What matters is how it works.  You'll know after you try it if your crush was good.

[ravenwater]

DMTaylor gives good guidelines above, and others are on target here as well, from my personal experience and that of my acquaintances. My assessment from the picture is you are in the ballpark (many loose hulls) but could go a bit tighter. I've found that for my mash in an orange cooler with a bottom screen a setting of .037 is the sweet spot where I get good efficiency but no stuck sparge for most grains. Accounting for the type of mashing you're doing is a good idea - variations of brew in a bag can stand much more flour. As others have indicated crush results at a given setting may vary for different grains. I sometimes use Malting Co of Ireland's pale ale malt which is plumper and I have to go up to .042 or so for an equivalent crush. I use a mechanic's feeler gauge to verify my gap.

[majorvices]

The crush looks good. You have preserved the husk integrity while exposing all of the grain inside. You don't have too much fine powder and no whole uncrushed kernels. At the very least it is a good starting point to crush finer.

[Joe_Beer]

Bear in mind that grain crush varies depending on what grain you crush.

Makes sense. I'm just using 2-row Pale Malt in the picture. The recipe I'm using has some Chit and Crystal 120 as well but I think the Crystal is just 2-row that's been baked for a while so I would guess the same size?

If your adjuster doesn’t have marks on it (like mine), you’ll want to mark it with some sort of indication...
...
If you’re using all malt barley you don’t need rice hulls.

Once I get it dialed in that will be helpful to make sure it hasn't moved. For now I just have a piece of shimstock to gage the gap. I'll likely be adjusting it after the next brew. I had a stuck mash a couple months back and it sucked so I just threw in some rice hulls on the next batch and it went fine.  I did end up switching to brewing in a bag after that (in the Foundry) though so that probably changes everything haha

Doesn't matter how it looks or what your gap is. What matters is how it works.  You'll know after you try it if your crush was good.

Yeah, understandably not a one-size-fits-all here. For a new guy like me though, having a starting point is kinda nice. Like driving a tractor for the first time - It was helpful knowing the throttle was on the steering column heh

My assessment from the picture is you are in the ballpark (many loose hulls) but could go a bit tighter. I've found that for my mash in an orange cooler with a bottom screen a setting of .037 is the sweet spot where I get good efficiency but no stuck sparge for most grains. Accounting for the type of mashing you're doing is a good idea - variations of brew in a bag can stand much more flour.

That's really useful. I do have a brew bag in my foundry but not sure how much flour can get through. I've dropped the gap to .032" and ran another handful through it. Looks like maybe 25% flour? I dunno. Another pic on black paper this time to make it a little easier to see. Like Denny kinda hints at though, I won't really know until I give it a try : https://imgur.com/a/RXq3auo

You don't have too much fine powder and no whole uncrushed kernels. At the very least it is a good starting point to crush finer.

Thanks for having a look. I maybe open it back up a bit. but good to know the first pic is in the ballpark anyway.