The dreaded grain mill issues thread

[rtstrider]

Hey all! I have a Northern Brewer Hullwrecker. I've had this since December 2020 and have brewed quite a bit with this. At first it worked great! Then about 9 months in or so it quit grabbing the grains. I found the "How to clean the grain mill" post in these forums and that fixed the issue. Welp I ran into the same issue again yesterday, took apart the grain mill, cleaned everything including the rollers with a wire brush, relubed everything with canola oil (that's all I had that was food grade oil), tried running grains through the mill again and nothing. I figured what the heck and tried running a handful of jasmine rice, for testing/cleaning, and that worked flawlessly. I do run a very tightly gapped mill in the .024 range but that's worked previously without any issues. The reasoning for the tighter gap is I've noticed quite a jump in efficiency. All my brews are dialed in to the new efficiency which is what I was getting with BIAB previously. I have a 3 tiered setup and fly sparge now. My question here is should I try widening the gap or should I start saving for a better grain mill? If a better grain mill is the better option then I have a few that I've been eyeballing

Mighty Mill 3 roller
https://www.morebeer.com/products/mighty-mill-3-roller-grain.html
The reason I like this is the rollers are geared so both rollers are constantly turning without the need for gravity/grains. Now I'm not too sure if these are built to last or the build quality of the steel rollers so that's a big question mark

Monster Mill 3 roller
https://www.morebeer.com/products/monster-mill-mm3-3roller-grain.html
This is the other option I've been eyeballing. I've read quite a few good reviews on this brand including on this forum. They definitely do seem to hold up over time. The downside is the bearings which may need to be replaced over time. This is why the geared mill is looking more attractive

 

[eric19312]

I've got the MM3 you linked. Used it to replace my old barley crusher. It works well but after a couple years I find it did start to sometimes fail to grab grains and I poke it with my old plastic spoon I used with my barley crusher. Should probably take it apart and clean the rollers but haven't had issue I wasn't able to resolve within 30 seconds of fussing with it. The gears do seem like a good idea but after about 6 years with a barley crusher and 3 years with this unit I've not seen any indication on either unit of bearings needing to be replaced. I do go through a lot of grain - typical brew day is 35+ pounds and I tend to brew every 3-4 weeks.

 

[rtstrider]

I've got the MM3 you linked. Used it to replace my old barley crusher. It works well but after a couple years I find it did start to sometimes fail to grab grains and I poke it with my old plastic spoon I used with my barley crusher. Should probably take it apart and clean the rollers but haven't had issue I wasn't able to resolve within 30 seconds of fussing with it. The gears do seem like a good idea but after about 6 years with a barley crusher and 3 years with this unit I've not seen any indication on either unit of bearings needing to be replaced. I do go through a lot of grain - typical brew day is 35+ pounds and I tend to brew every 3-4 weeks.

I brew 5.5 gallon batches at least every other week going through about 30lbs or so of grain a month. The main reason for liking the geared rollers is it seems like there would be much less futzing around with the rollers. Oh yeah they would still need to be cleaned, but, in my head it at least makes sense that this would help. I'm not a machinist, mechanic, or engineer though so I could be way wrong lol

 

[MaxStout]

Is the knurling on the rollers starting to wear? Perhaps that's why it doesn't grab kernels like it should. Look at it with a magnifying glass and see if the knurled points have become rounded off.

If you switch to a MM, the sleeve bearings shouldn't be a problem as long as you don't apply any side-loading to the shafts (i.e., pulley/belt). Using direct drive or a gearbox should be OK.

 

[rtstrider]

Is the knurling on the rollers starting to wear? Perhaps that's why it doesn't grab kernels like it should. Look at it with a magnifying glass and see if the knurled points have become rounded off.

If you switch to a MM, the sleeve bearings shouldn't be a problem as long as you don't apply any side-loading to the shafts (i.e., pulley/belt). Using direct drive or a gearbox should be OK.

I do use a corded hand drill if that makes a difference. I just cleaned the rollers again. I'll get some food grade mineral oil and try relubing with that. It'll be two weeks or so before the next brew day though so we will see. Next one is a light batch anyways since it's an American Lager. Only 6 lbs of grain to crush

 

[MaxStout]

Drill probably OK, not as much side force with that.

 

[Deadalus]

I recently started conditioning my grains. I don't know if it would help or hinder the grabbing issue. It does make the grain a little softer yet stickier with a lot less dust.

 

[rtstrider]

I recently started conditioning my grains. I don't know if it would help or hinder the grabbing issue. It does make the grain a little softer yet stickier with a lot less dust.

I've looked at conditioning grain but that's just not something I'd like to do if possible. It's just extra work on an already busy brew day lol

 

[Deadalus]

I've looked at conditioning grain but that's just not something I'd like to do if possible. It's just extra work on an already busy brew day lol

Well you are running a very tight gap already and if you aren't having issues with stuck sparges I'm not sure it would benefit you a whole lot. I don't find it adds much time at all however. I just spritz and stir the grain while weighing it out. I get it though. I have a pH meter but I haven't used it yet because I am often fussing with other things during the mash.

 

[Oleson M.D.]

Food grade WD-40.

 

[rtstrider]

Wanted to respond back. I'm not too sure this is a grain mill issue after all. It may be more of an "operator" issue lol Had my first stuck sparge yesterday. Pulled out the ol feeler gauge and the gap was TIGHT. Found this exBEERiment | Impact Grain Crush Size Has On An American Pale Ale and set the mill back to .030 and will use that for a few batches and see how it turns out. In the meantime I do have another question

Next batch is Cream of Three Crops. This uses Minute Rice and I always toss this in the mash untouched. Would there be any benefit/harm in running the minute rice through the grain mill with the base malt? Would it even be worth doing?

 

[passedpawn]

Wanted to respond back. I'm not too sure this is a grain mill issue after all. It may be more of an "operator" issue lol Had my first stuck sparge yesterday. Pulled out the ol feeler gauge and the gap was TIGHT. Found this exBEERiment | Impact Grain Crush Size Has On An American Pale Ale and set the mill back to .030 and will use that for a few batches and see how it turns out. In the meantime I do have another question

Next batch is Cream of Three Crops. This uses Minute Rice and I always toss this in the mash untouched. Would there be any benefit/harm in running the minute rice through the grain mill with the base malt? Would it even be worth doing?

I've done this exact thing - ran the rice through with the grain. I had no problem with that.

BTW, I have that might mill 3 geared. I love it. Such a great upgrade to my old non-geared JSP mill.

 

[day_trippr]

There is no gain in milling "minute rice". Probably no harm, either. I wouldn't bother.
Otoh, milling actual rice can damage a mill. Don't do that

Cheers!

 

[rtstrider]

And it's not grabbing grains again no matter what I do. I've tried cleaning up the Hull wrecker and all that jazz. I'm beginning to think there's something up with the rollers themselves

 

[rtstrider]

I took the mill apart again. I noticed these are sealed bearings. There was a good bit of grain dust caught between the roller and sides. I cleaned that out, did not re-oil as I think this may be the culprit, and put the mill back together. The rollers are spinning much more freely than they were before. Fingers crossed this is a permanent fix!

 

[rtstrider]

Northern Brewer stated since this happened a year after purchase (purchased December 2020) it is not covered under warranty. I've asked if they can point me in the direction of replacement rollers if needed. Hoping my cleaning is the permanent fix and if not maybe better rollers might be

 

[mashpaddled]

Do you have this problem if you widen the gap somewhat? I wonder if the gap is too tight for the rollers to force in the grain. Rice is smaller so it would make sense that you wouldn't have problems with rice if that's the case. If a tight crush is necessary, then you may need to crush first on a wider gap, adjust down and run it back through.

 

[rtstrider]

I've tried widening the gap with a feeler gauge and still no go. This was before the mill was cleaned. I need to try running a few batches through this to see if cleaning the "crud" is the ultimate fix

 

[Konadog]

Well, if you do end up looking for a new mill, I can recomend the Mighty Mill 3 roller. I've only had it 6 months (13 5 gallon brews) and love it. The only thing I wish it had was a hopper extension.

 

[rtstrider]

Well, if you do end up looking for a new mill, I can recomend the Mighty Mill 3 roller. I've only had it 6 months (13 5 gallon brews) and love it. The only thing I wish it had was a hopper extension.

I'll eventually bite on the monster mill 3 roller but it's going to be a few years. Saving up for an all in one unit first

 

[beren]

I wish I could justify the geared MM3

 

[rtstrider]

I wish I could justify the geared MM3

The only reason I'm leaning towards the Monster Mill 3 roller is this verbiage

https://www.morebeer.com/products/monster-mill-mm3-3roller-grain.html
"We use a superior grade of steel that is much harder than what is found on most comparable products and should last almost twice as long."

• Rollers last for 12,000 - 15,000 lbs of grain

This would equate to over 1000 batches easy in my case. The hullwrecker has only lasted for less than 30 or so 5 gallon batches. The jury is still out on it though. Really need to run a few more batches worth of grain through it now that it's clean before making any final judgement.

 

[jambop]

Having read through the thread I get the idea that maybe you have too tight a gap in any case but that may have nothing to do with your problem. As I understand it crushing the grains fine only really speeds the rate of conversion and does little, if anything for efficiency ... in fact could reduce efficiency due to less efficient sparging ?

 

[beren]

It could be a too tight gap but more likely the knurls get worn down and don't have sharp edges anymore, so it doesn't grab the grain unless the gap is quite large.

 

[seatazzz]

Late to the party, but have you tried reversing the rollers? I've read that this can extend the life of the mill.

 

[Zambezi Special]

Maybe widening the gap a bit and double milling?
My mill has a bit of a weird issue, sometimes it struggles to grab the grain, sometimes not. So I put a little bit of grain, push it a bit and when ut grabs, I put the rest. No idea if that would help you

 

[rtstrider]

It's the rollers. I'm just going to futz around with it until I have enough saved up for a 3 roller Monster Mill. End goal is to move to an all in one system and use a brew bag so thinking the 3 roller setup will help due to a double crush. Also want something that's going to last more than 20 5 gallon brew days lol

 

[IslandLizard]

It's the rollers.

That is roundout terrible and inexcusable customer "service!"
Have you seen any other reports on that mill being crappy?

If they were close by I would have given them the "piston treatment." My dad started that, way back...

I'd avoid Northern Brewer like the plague, customer beware!

 

[rtstrider]

That is roundout terrible and inexcusable customer "service!"
Have you seen any other reports on that mill being crappy?

If they were close by I would have given them the "piston treatment." My dad started that, way back...

I'd avoid Northern Brewer like the plague, customer beware!

To be fair they were looking for replacement rollers in the warehouse a few weeks ago but that's the last I'd heard from them. I can't fault a company for standing by their warranty terms and such either. This was warrantied for 1 year and well these issues happened after about a year a 3-4 months of ownership. Now with that said I would hope this thread stands out as a warning to others on this particular grain mill. I have had a previous issue with Northern Brewer and they did resolve it. I ordered crushed grain (prior to owning a grain mill) and they provided a gift card code to cover the price of the grains. I was able to find someone in town to crush the grains so that was a plus. I'd really prefer not to bash a company over a rebranded faulty product that failed right outside of warranty. I won't buy anything from Northern Brewer outside of yeast/hops/grains that I can't get from Morebeer going forward. Meaning...Nothing is changing in my purchasing habits lol

 

[rtstrider]

Northern Brewer said they had a returned grain mill that was in working order. They're shipping that out. Said I can use that as is or for parts. It's supposed to be here Tuesday. I won't be crushing grains again for 2 weeks or so though. Either way I'll keep this thread updated!

 

[IslandLizard]

Northern Brewer said they had a returned grain mill that was in working order. They're shipping that out. Said I can use that as is or for parts. It's supposed to be here Tuesday.

Lucky you!
That's finally some good news, and a very decent offer from them. Hopefully it wasn't returned for a similar issue.

You've not been milling (whole kernel) rice on your mill, have you?

 

[rtstrider]

I've run maybe 2lbs of it through for testing purposes over the whole time but that was way after these issues started. Anywho I'm hopeful this new replacement works and will hold up for many batches to come

 

[IslandLizard]

I've run maybe 2lbs of it through for testing purposes over the whole time but that was way after these issues started. Anywho I'm hopeful this new replacement works and will hold up for many batches to come

If the steel is too soft for the milling application, I wonder if you could harden it...

 

[rtstrider]

If the steel is too soft for the milling application, I wonder if you could harden it...

You know I wouldn't even know where to begin with that lol

 

[IslandLizard]

You know I wouldn't even know where to begin with that lol

There are machinists on the forum, maybe start a thread on that?

It's basically heating to certain temps, holding it there for some time, then cooling it down quickly, like dropping it into a vat with water or oil. It would help knowing the alloy used, but I reckon it's some mild steel, and was never hardened. Most of that stuff is made in China, with wildly varying or non-existent QC.

There are methods to test the hardness of the steel you have on hand.

Your existing rollers good be re-knurled, then hardened too, but unless you know someone who takes homebrew for doing it, the cost is likely more than a new Monster or Crankenstein mill.

 

[Saunassa]

My hull wrecker has worked well for me, roller spacing is 30-34 mils depending on which credit card I used to check. A gap less thenp 25 mils and the grains would sometimes 'ride' on the rollers.
I was given a MM3 w/2" rollers and hopper extension. This beast with a big drill is amazing but will not fit on shelf like the hull wrecker will.

 

[rtstrider]

There are machinists on the forum, maybe start a thread on that?

It's basically heating to certain temps, holding it there for some time, then cooling it down quickly, like dropping it into a vat with water or oil. It would help knowing the alloy used, but I reckon it's some mild steel, and was never hardened. Most of that stuff is made in China, with wildly varying or non-existent QC.

There are methods to test the hardness of the steel you have on hand.

Your existing rollers good be re-knurled, then hardened too, but unless you know someone who takes homebrew for doing it, the cost is likely more than a new Monster or Crankenstein mill.

Monster Mill 3 is the end goal. Right now my brew funds are being saved for an All in One setup. I like the Foundry but I'm really trying to hold out for the Brewzilla 4th gen when it's available. Once that's done and I get all the stuffs (brew bag, CASS chiller, various different add on's and nylon insulator sleeve, etc) I'll start saving for the grain mill...After that though it'll be time to convert the Pin Lock keg fittings to ball lock and then invest in real beer taps instead of the cobra taps lol. Still have a ways to go, but, it's awesome to see how much equipment has been gathered over 5 years of brewing too!

 

[IslandLizard]

Monster Mill 3 is the end goal.

Beware, from what I've read it's a real hassle to adjust the gap for different grain sizes on an MM3.
My MM2, like most 2 roller mills, is easy for that.

 

[Broken Crow]

If the steel is too soft for the milling application, I wonder if you could harden it...

Unfortunately no... I used to do heat treating; A shaft for such an application is first carbed & hardened, then drawn back down to a softness/hardness appropriate to the application, and then, (importantly straightened..[As the process will alway warp the part to some degree], only after this are your knurls, cutting edges or whatever, then machined into the shaft. Trying to do it all after machining wrecks edges. It also changes the size and fit ever-so-slightly, and it's a crap shoot from the get go if it's even an alloy suited to heat treating.
(sorry I can't give a more detailed explanation, I lost a lot of that to brain-injury)

 

[rallenhall]

I have an MM3, and have no interest in changing the gap that's set for my preferred barley malt crush. I kept my first mill, a two-roller Barley Crusher, primarily for its easy adjustability and use with specialty malts such as rye.