Author Topic: grain crush issue with Monster Mill 3  (Read 309 times)

Offline mugwort

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grain crush issue with Monster Mill 3
« on: June 09, 2014, 09:10:47 PM »
I'm about to write Monster Brewing with a question about the performance of my recently acquired 3-roll mill, but I thought I'd put the same questions to the experienced crew on this forum as well.

I am having an issue achieving a finer crush with my new MM3 2.0.  As instructed on the provided sheet, I ran my first brew with the mill at factory setting (approximately .045"), and using a 1/2" corded DeWalt it mowed through the grain effortlessly.  Mash drained quickly, without a hint of sluggishness but efficiency suffered (about 65%).

So for my next brew I thought I'd adjust the gap tighter for a more thorough crush.  As suggested in the documentation, I put a tic mark to indicated the default gap before loosening the set screws.  Facing the mill from the drive shaft side, I turned the adjuster a small amount (5 or 10 degrees maybe) to reduce the gap to a little over a .035".  I turned the knob on the other side a corresponding amount in the same absolute direction, and then confirmed with a gauge that the gap was the same on both sides of the roller.

To my surprise, the crush came out as coarse as before I adjusted the mill.  At this point I figured out why.  The bulk of the grain was now channeling through the fixed gap side instead of through the adjusted gap side.  No matter what gap I set below and up to .045", the majority of the time the grain was directed though the fixed rollers rather than the rollers with the adjustable gap.  Due to this behavior, I was forced to double crush the all the grain.

My question is, how can I get a tighter-than-default crush on this mill?  There must be something I'm missing here.  I don't understand why the grain flow keeps switching between the two roller paths.

Anyone else have any experience with this?
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Offline ticktock

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Re: grain crush issue with Monster Mill 3
« Reply #1 on: June 10, 2014, 02:39:19 PM »
I have set my three roller mill to the .04 wide on the rollers and I multi pass the grain through the mill and I have not had a stuck mash and have been getting about 90% yield.  I have to dial back the grain bill to reach my expected OG.  Instead of say 10 lbs, I'm going to use 8.5 lbs  I have the older MM-3.  Your setting may be slipping and not locking in. Check your locking feature on the newer model.

Offline Thirsty_Monk

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Re: grain crush issue with Monster Mill 3
« Reply #2 on: June 10, 2014, 03:09:30 PM »
I also have older model and I am always puzzled which bottom roller it goes thru. My adjustment is about .041 with great efficiencies. I put a couple of tons thru this mill over the course if 4 years.

Good luck.


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Offline arustyt

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Re: grain crush issue with Monster Mill 3
« Reply #3 on: June 10, 2014, 03:36:10 PM »
I have the older version of the MM3.  One thing to keep in mind is that the adjustable roller is mounted off-center in the rotating bearing assembly so rotation changes the gap.  As a result, there are actually two angles where you will have a given gap between the adjustable roller and the drive roller.  One of those angles will give you a wider gap between the adjustable and idle rollers, the other will be narrower.  I think what you want to do (at least I did with mine) is adjust so the gap between the adjustable and idle rollers is the narrower of the two settings. In this position I think adjustable-drive gap should be wider than the adjustable-idler gap making it the easier/preferred path for the grain.

I am not sure if this makes sense, but I hope it helps.

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Offline rjharper

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Re: grain crush issue with Monster Mill 3
« Reply #4 on: June 16, 2014, 09:45:26 AM »
I have the older version of the MM3.  One thing to keep in mind is that the adjustable roller is mounted off-center in the rotating bearing assembly so rotation changes the gap.  As a result, there are actually two angles where you will have a given gap between the adjustable roller and the drive roller.  One of those angles will give you a wider gap between the adjustable and idle rollers, the other will be narrower.  I think what you want to do (at least I did with mine) is adjust so the gap between the adjustable and idle rollers is the narrower of the two settings. In this position I think adjustable-drive gap should be wider than the adjustable-idler gap making it the easier/preferred path for the grain.

I am not sure if this makes sense, but I hope it helps.

Rusty

This. I have the new MM3. arustyt is correct that the adjustable roller bearings are off axis.  Also be sure to rotate the adjustment so that your target gap is between the actively driven roller and the third roller.
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Offline mugwort

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Re: grain crush issue with Monster Mill 3
« Reply #5 on: June 23, 2014, 10:21:21 PM »
I have the older version of the MM3.  One thing to keep in mind is that the adjustable roller is mounted off-center in the rotating bearing assembly so rotation changes the gap.  As a result, there are actually two angles where you will have a given gap between the adjustable roller and the drive roller.  One of those angles will give you a wider gap between the adjustable and idle rollers, the other will be narrower.  I think what you want to do (at least I did with mine) is adjust so the gap between the adjustable and idle rollers is the narrower of the two settings. In this position I think adjustable-drive gap should be wider than the adjustable-idler gap making it the easier/preferred path for the grain.

I am not sure if this makes sense, but I hope it helps.

Thanks for the response.  The adjustable-idler gap is definitely on the wide side.  Trying to reconcile the off-axis design you're describing with the specifications/instructions provided on the site/with the mill.  There seems to be no direct discussion of this aspect of adjustment in the documentation.  Hopefully I'll have time to fiddle with it this weekend to try to get it right.
Baby T Aleworks | 100% Organic Abode-Crafted Ales | San Gabriel, CA | On tap...
Hellhound (stout on pasillas) 9% * Republican Enclave Red Lager 5.5% * Quado 3 Belgian Dark Strong 10% * Browneyes Belgian Porter (on cacao and coffee nibs) 6.5% * empty * Belgian Blonde with goji berries 7% * Heatstroke IIPA 8.5% * London Red 5.5% * Ziggurat Dark Sour 9%