Introduction: Corona Mill Mods for All Grain Brewing

The Corona Mill is a cheap alternative to the more expensive roller mills used to crush grains for brewing. Roller mills start at $100 and quickly go up in price. A Corona Mill can be had for as little a $20. With three modifications---two minor, one a little more intense---it can be as effective or even more effective at crushing grains for home brewing. The lower cost will let you save money on other things like good brewing kettles, jet burners, and pumps.

Step 1: The Handle (Manual to Motorized)

This tip has been out there on the internet for a long time. The handle is held on by a thumb bolt. You can replace this thumb bolt with a 5/16" bolt and then use a 1/2" socket on a drill (or some other motor) to crank out your cracked grains.

Step 2: Another Minor Fix

This is another tip that's been out there a long time. See the exposed gap where the bolt is. Fill that with washers. Most tips around the internet say two. I say four because of the next mod.

Step 3: The Major Mod

I regret that I didn't think about making an instructable about this until after I'd finished it because it worked so well and it really wasn't that hard to do. The auger comes with a burr attached to it by a metal cap and a cotter pin. This makes for a very uneven burr. It's got a lot of wobble. I wanted to make it as even against the burr attached to the body as possible. The way I came up with is to cut threads on the post of the auger and use a nut and rubber o-ring to hold it on.

Luckily the post sticking out is 1/2". I used a 1/2"x13 die to cut the threads. It took a while. Not as long as you might expect though. I think all together I cut the threads in about 10 minutes.

The helped out quite a bit in leveling the burrs to each other. Because of the limited space I used a jam nut (they're thinner). If you could find a very thin lock nut (aka stop nut) then go for that. In this case the o-ring keeps pressure on the nut and keeps it in place. You could use glue or loctite to keep it in place if you wish. The o-ring also helped even out the unevenness. If you have access to a mill and lathe you could make one hell of a grinder out of a corona mill.

Step 4: Another Mod

Some people don't like the size of the hopper. You can use a 2 or 3 liter bottle to augment the size. I even heard of a guy using an empty 5 gallon water cooler bottle for this. I think he cut it down and screwed it to the existing hopper.

Get a corona mill. Well worth it for the money you save. And after these mods it'll produce a consistent grind that's easily adjusted based on the size of the grain. Having crushed 12lbs of grains I can assure you that you'll have very little powder from them (I had about 3/4c) and good sized hulls to keep you from getting stuck during sparging.

Comments

author
jimmiek made it!(author)2015-03-11

I like this idea, there's one LHBS down in Knoxville on Martin Mill Pike that is too cheap and inexperienced to go out and buy a $100 grain crusher, but once in a long while I have to buy from them instead of the one on Kingston Pike who crushes it for us. This would be just right for those odd times when I have to buy a few pounds of grain from El Cheapo!

Thanks for this instructable!

author
Dark+Solar made it!(author)2014-05-07

I'm a hair away from buying one but have been unable to locate a technical blow-apart and so still have reservations; the sardine key & wing nut combo outside of the bail--what do they do? Related to grind coarseness adjustment?

Also, working primarily with corn/sorghum malt; do you have a ball-park estimate for maximum burr-to-plate gap with available after step 3 mod?

author
dlewisa made it!(author)2014-05-08

Yes the wingnut is for adjusting coarseness.You don't get the best or most even grind with this thing. A roller mill would be the best bet, but for the price this thing is good enough. It's been so long since I made a batch of beer I couldn't tell you what the gap is. Sorry.

author
wmatos68 made it!(author)2014-09-19

what do you mean when saying "If you have access to a mill and lathe you could make one hell of a grinder out of a corona mill"? Is there a better way?

author
dlewisa made it!(author)2014-09-19

Geez, this is an old instructable and I haven't made an all-grain beer in a while. I can't remember what I meant. Probably it would be easier to cut the threads with the lathe. And I think the burr that you can remove wasn't very flat where the nut and rubber o-ring press against it so you could put it on a mill and level it out. It would give a more even gap for a consistent grind.

author
Kamsi made it!(author)2013-10-18

Hello All! Can anybody tell me where I can purchase the Corona Mill in Vancouver Canada. Many thanks for your help!

author
dlewisa made it!(author)2013-10-18

Amazon.ca or www.midwestsupplies.com. You can also search for a victoria mill. Same thing.

author
jessyratfink made it!(author)2012-05-23

Love the tip about making it motorized - very smart. :D

author
dlewisa made it!(author)2012-05-23

Nothing better than making life easier. . . . And making alcohol cheaper.

author
BigCommieNat made it!(author)2012-05-23

I've been putting off the purchase of a mill for years now - I think you've just sold me on finally making the plunge:)

One question- it looks like you've got this locked down to just grinding for brewing. is it possible/what would it take to adjust the grind down to make flour for baking?

author
dlewisa made it!(author)2012-05-23

It does retain its functionality as a flour mill. All you do is adjust the burrs closer together.

author
dreiseratops made it!(author)2012-05-23

I got one very similar looking to this. Mine has no top cover & the hopper is shorter but the grinding doesnt go much finer than meal before scraping the aluminum together & I hear thats not good to eat.
Cheap though. :)

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