Help! Problem Milling Grain

[plan_ahea]

Hi all,

I brewed my first AG BIAB last weekend, and thought I'd save time on brew day by milling the grain the night before. However, the mill had a hell of a time "grabbing" the grain, and I had to empty & refill the hopper half a dozen times to get the grain to catch, which took way longer than expected.

I'm milling on the OBKrusher, which I believe is identical to the Cereal Killer. Gap was set to 0.030" (credit card), and I was happy with the crush, when it eventually made it through the mill (got 83% brewhouse efficiency, not bad for my first AG brew!).

Living in central Alberta, Canada, the humidity is pretty darn low. Would that, or anything else, contribute to the grain not "catching" in the mill? I had it hooked up to an electric drill, tried switching the drill's direction back and forth, shaking the mill to settle the grain, etc. I just want to avoid this in my next brew!

 

[blizz81]

You sure the electric drill had enough torque?

 

[vincentAlpha]

When in doubt try cranking it by hand if you've got a handle. That'll narrow down any mechanical problems to the mill and not the drill you are using. I wound up doing that and ended up switched from my 120V Makita to my little 12V Dewalt since it has loads more low end torque surprisingly enough, also way easier to get a nice even crush.

 

[barnaclebob]

Thats very strange. Are the rollers rough? One workaround could be to mill the grain at a very wide setting, then send it through again at .030.

 

[watermelon83]

Is the idler rolling turning freely? I have seen this with both idlers not being parallel and when the grain bin was touching the roller.

 

[BierGut]

This might seem silly but were the rollers going in the right direction? The first time I used my mill I had my drill going counter clockwise so it was pushing the grain up n' over the rollers instead of pulling it through. I refilled the hopper 3 or 4 times before I realized and was like, duh.

 

[mwjtennis]

Hi all,

I brewed my first AG BIAB last weekend, and thought I'd save time on brew day by milling the grain the night before. However, the mill had a hell of a time "grabbing" the grain, and I had to empty & refill the hopper half a dozen times to get the grain to catch, which took way longer than expected.

I'm milling on the OBKrusher, which I believe is identical to the Cereal Killer. Gap was set to 0.030" (credit card), and I was happy with the crush, when it eventually made it through the mill (got 83% brewhouse efficiency, not bad for my first AG brew!).

Living in central Alberta, Canada, the humidity is pretty darn low. Would that, or anything else, contribute to the grain not "catching" in the mill? I had it hooked up to an electric drill, tried switching the drill's direction back and forth, shaking the mill to settle the grain, etc. I just want to avoid this in my next brew!

Do a quick search on conditioning the grain (just very lightly wetting with a spray bottle)

 

[Gavin C]

I had problems with my mill when I first got it.

Check the hopper is full seated.
make sure the non-driven roller is spinning freely. Took me three batches to realize this.

Once I loosen the locking nuts for the slave roller a little bit it would stay where I wanted it to but could spin freely. Minimal problems from now on. Occasionally I need to press the slave roller if it stops catching the grain but overall its working well.

Time to mill my grain is now a couple of minutes as opposed to 30+ minutes with the same problems you describe.

 

[Hello]

My issue was my drill was not on the right setting. I would definitely try to look into that. Second, check to make sure the rollers are going in the right direction. I actually made that mistake two weeks ago.

 

[blizz81]

make sure the non-driven roller is spinning freely. Took me three batches to realize this.

Once I loosen the locking nuts for the slave roller a little bit it would stay where I wanted it to but could spin freely. Minimal problems from now on. Occasionally I need to press the slave roller if it stops catching the grain but overall its working well.

For me, my BC slave roller gunked up after just a couple 5 gal batches. After that I went through the cycle of disassembling it and cleaning it and reassembling it only to have it gunk up again after 3-5 batches probably 3 times.

The last time I rebuilt it I used some gun oil on the end of the shaft where it sits in the housing. Have not had one problem since in probably 10-12 batches.

 

[Gavin C]

For me, my BC slave roller gunked up after just a couple 5 gal batches. After that I went through the cycle of disassembling it and cleaning it and reassembling it only to have it gunk up again after 3-5 batches probably 3 times.

The last time I rebuilt it I used some gun oil on the end of the shaft where it sits in the housing. Have not had one problem since in probably 10-12 batches.

Taking it all apart at some stage will likely be needed in addition to oiling the rollers. I'm a bit wary of doing it as my mill is a very flimsy one. Hopefully it would hold up just fine but I'd be concerned I could break it.

 

[blizz81]

They're pretty basic, it should be fine. Yeah, it should be a maintenance-type item, but not nearly as often as I originally thought. I know I had tried to grease the roller with something, perhaps automotive grease, when I was rebuilding it the first few times. Just including in case the OP finds the slave roller is seized so they don't go down my path, or are at least aware of my path.

 

[plan_ahea]

You sure the electric drill had enough torque?

Yup. When it actually did catch the grain, there was more than ample power to crush it.

Are the rollers rough? One workaround could be to mill the grain at a very wide setting, then send it through again at .030.

Yes, rough rollers (they're also clean). I suppose milling it twice, adjusting between passes, is possible, but that sounds like a PITA to have to do every brew day. I'd rather set-and-forget.

Is the idler rolling turning freely? I have seen this with both idlers not being parallel and when the grain bin was touching the roller.

Yes, it's spinning freely, and they're as parallel can be.

This might seem silly but were the rollers going in the right direction?

Yup, checked this a couple times.

Do a quick search on conditioning the grain (just very lightly wetting with a spray bottle)

Might have to give this a try!

I had problems with my mill when I first got it.

Check the hopper is full seated.
make sure the non-driven roller is spinning freely. Took me three batches to realize this.

Once I loosen the locking nuts for the slave roller a little bit it would stay where I wanted it to but could spin freely. Minimal problems from now on. Occasionally I need to press the slave roller if it stops catching the grain but overall its working well.

Time to mill my grain is now a couple of minutes as opposed to 30+ minutes with the same problems you describe.

Hopper is seated properly; free roller has no problem spinning.

I think I'll have to try either a) conditioning the grain prior to milling, or b) widening the gap and double-crushing. I'm trying to keep things as streamlined and simple as possible, so I'll have to figure out whether it takes less time to moisten the grain with a spray bottle or just run the grain through a wider gap twice.

 

[Gavin C]

You could do the first pass at a wider gap and then reduce it to a more optimal smaller size for your crush. Best of luck figuring things out.

 

[Brettomomyces]

I just recently overtightened my set screws which held the idle roller in place...took me a good 15 minutes to realize what was going on. Could check that too.

Edit, just saw your idle roller is spinnin free.

Is the frame absolutely flush with each piece? I have had that happen when I remounted my MM2 on a new bench.

 

[RedstoneBrewing]

I've also got the OBKrusher and initially had the same problem when starting out. Took it apart, cleaned it, etc. nothing worked. I would spend 45 minutes crushing grain for a 5 gal batch because I was constantly reaching underneath to help the rollers catch the grain.

Conditioning the grain prior to milling made a huge difference for me. It was like night and day and I was able to finally dial in my system/efficiency. (I previously also tried double milling at a wide gap but found the results a bit erratic)

However, now (mostly because I'm lazy) I stopped measuring the gap and have just been eyeballing the crush. I have my mill locked in at a wider gap which catches the grain (without conditioning) and yields ~70% efficiency, so that is good enough for me!

 

[ImpendingDisaster]

Hi all,
Living in central Alberta, Canada, the humidity is pretty darn low. Would that, or anything else, contribute to the grain not "catching" in the mill? I had it hooked up to an electric drill, tried switching the drill's direction back and forth, shaking the mill to settle the grain, etc. I just want to avoid this in my next brew!

Howdy from southern Alberta! I have the same mill and the same problem whether I turn the mill by hand or by drill. With the hopper full it works for a while then spins out when the hopper is about 2/3 full. Smacking the thing, shaking it, works somewhat. Turning it backwards just lets whole grains fall through. One the hopper finally does get to about 1/3 full or less, it catches and the rest of the crush is problem free. No idea why, but that has been my experience.

What I did find works is to only throw a big scoop or two of grains in at a time. It goes pretty quick. I just weigh all the grains into a big bucket and use a bowl that hold maybe 1/2 pound in at a time. It adds only seconds to the total time to crush, not counting the time saved by no roller spinning.

I also do a second crush. The first one is with the rollers a little wider than credit card thickness, the second is measured with a credit card. No idea the actual measurement. The second crush is absolutely problem free with a full hopper, and with a drill it is all over in a matter of two minutes.

 

[plan_ahea]

I've also got the OBKrusher and initially had the same problem when starting out.
(...)
Conditioning the grain prior to milling made a huge difference for me. It was like night and day and I was able to finally dial in my system/efficiency. (I previously also tried double milling at a wide gap but found the results a bit erratic)

Howdy from southern Alberta! I have the same mill and the same problem whether I turn the mill by hand or by drill.
(...)
What I did find works is to only throw a big scoop or two of grains in at a time. It goes pretty quick. I just weigh all the grains into a big bucket and use a bowl that hold maybe 1/2 pound in at a time. It adds only seconds to the total time to crush, not counting the time saved by no roller spinning.

I also do a second crush. The first one is with the rollers a little wider than credit card thickness, the second is measured with a credit card. No idea the actual measurement. The second crush is absolutely problem free with a full hopper, and with a drill it is all over in a matter of two minutes.

Love me some fellow Canadians! Thanks for the tips, eh. I'll give these tips a shot next brew day!

 

[kombat]

My rollers have started to spin and refuse to grab the grain lately too. I gave them a good scrub with a wire BBQ brush and it fixed the problem. I'd suggesting giving that a try.