Grain Mills + Stones/rocks In Grain?

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WitWonder

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I've managed to acquire a motor for my new Crankandstein 3D and the plan is to attach a shaft directly to the mill, rather than use pulley's etc. I've read a few comments on various threads that talk about the likely damage to the mill if rocks or stones or whatever is pulled through the mill. Given my motor has huge torque, whatever is put in the hopper will get sucked through the mill.

My question is how often have people seen rocks or anything else come through in their grain and where did you buy it from? I would have thought the grain is a food grade product and as such items like rocks (or anything else) would be a one in a million event and therefore pretty low risk.
 

domonsura

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I've seen sticks and bark in Weyermann malt (but funnily enough not in the Aussie malts), but never a stone - although I have heard of it and it is something to be aware / wary of.
Just make a point of ensuring that the drive to your mill can slip a little bit so if anything really crazy gets in there it won't blow your mill to bits..usually the belt slipping on pulleys would be enough to stop anything doing massive amounts of damage if you're quick about turning it off, but if you want to direct drive with a motor, put a keyway coupler and an aluminium key in there - if something then jams your mill, the key will shear, stopping the drive to the mill instead of dragging the offending object all the way through (hopefully).
My crank 3D is motor driven via a pulley and there's only just enough tension on the belt that the belt usually won't slip when milling - but if it gets too tough going, the belt slips. (I didn't plan it this way, I just didn't get around to putting a proper tensioner on it.)
I'm trying to get around to building a better mill stand with a new motor that is already geared down to 103rpm, so a direct drive will be an option, but in that case I will be using the keyway option.

Overall though, don't lose too much sleep over it - I think that possibly stones were a more common occurence in years gone by, but maybe not all that common these days.
 

paul

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The chance of a stone in is fairly small unless the header operator has got the comb way too low. When harvesting barley you only take the head off the top of the stem.
 

Steve

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Last year I had a run of stones in my Maris Otter (not just one bag). Big enough and hard enough to stop the rollers and gouge them :angry:
 

blackbock

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I've not had a stone yet, touch wood. But I would imagine it might be worthwhile dragging a strong magnet through the grist before crushing. Some small stones may stick to it.

In fact, you've just inspired me for my next project: affixing two rare earth magnets to my hopper!
 

Aaron

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I had al sorts of crap in some Powell's malt a couple of years ago and haven't been back since because of it. Never had anything nasty in any other brands.
 

jimi

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+ 1 for a stone
Didn't know what maltster it came from as I found only after combining all grain. It was small and didn't do much damaged, passed through & left a small dint in a roller or two.
 

white.grant

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I have seen bits of non grain material - bark and the like in my most recent mash (Weyermans Boho pils). I've also snapped the blades in a couple of coffee grinders on small stones in the coffee beans. So anything is possible.

cheers

Grant
 

bugwan

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....it might be worthwhile dragging a strong magnet through the grist before crushing. Some small stones may stick to it.
:blink:
Surely you'd only be finding iron ore by using a magnet!!
 

white.grant

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:blink:
Surely you'd only be finding iron ore by using a magnet!!

Bakeries use magnets to extract metal from the flour and the finished loaves - they're not looking for rocks , mainly its bits of the processing equipment that shred and break off into the product.

cheers

Grant
 

Tony

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I got a whole wheel off a John Deere harvester in a bag of ale malt once............ the mill ate it like it was soft butter

:p

Seriously though.......... i did get a stone once, cant remember the malt. It wasnt a big one and i recon the 2"ss rollers would have crunched it.

Found it while i was mixing a bit of water into the grain prior to milling so i never found out. It was about the size of 2 grains stuck together.

I would have thought the grain would be screened to remove anything bigger than the grain anyway.......... I doubt the big breweries would be happy with rocks in their big dollar mills.

cheers
 

WitWonder

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Yeah I reckon Tony. Like I said, I am pretty sure it's a food grade product and, as such, is subjected to the rigmoroles and exacting requirements of the food industry, just like other food stuffs. Although you do read about bits of metal and other debris entering things now and then...

I reckon I'll just set it up with a direct drive and if it happens it happens! Personally I think if it's the size of a bit of grain it won't do much harm to the rollers, but may do worse if ending up in my beer!


Cheers
 

scrogster

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Last year I had a run of stones in my Maris Otter (not just one bag). Big enough and hard enough to stop the rollers and gouge them :angry:
Strangely enough the only stone I ever had in some malt was also in Maris Otter. Only one tiny stone (small pea size), and I was cranking the mill by hand, so no damage done.
 

Frank

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I found a small stone the other day. Can't say where the stone came from but it was part of a combined malt that I recently purchased. It was a 3 shades of Stout ripoff, so my grain bill was the following, to add to my base malt:
Weyermann Pilsner2.0KgBairds Pale Chocolate0.6KgBairds Chocolate Malt0.3KgBairds Black Malt0.1KgI would put money on it coming from the Bairds Malt, because they were at the top of my bucket, but can not confirm.
As others have said, these grains have been screened, so the stone was just a bit larger than the malt.
My mill would have just crushed it with no damage.

Boston
 
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