Adjusting a Corona Grain Mill

After reviewing the threads here on grain mills, I broke down and bought a Corona for about $50.00. I assembled it but haven't used it yet. I have a question with respect to adjusting the plates or disks or whatever you call them. Palmer's book states that the plats should be .035 to .042 inches.That's fine but a Corona Grain Mill is not a precision piece of machinery. If I use a feeler gage and adjust the 2 side nuts to .045 the middle seems to have a lot more space between the Plates. How do other brewers adjust the plates to get a good grind. Do You use a feeler gage and if so here do you measure, on the sides or in the middle" Do you just play it by ear? Do you use different settings for different grains?

I don't use a gauge...I went through a few pounds when I got mine and marked, using a Sharpie, one setting for barley and one for wheat. I have to tweak these depending on the exact grain and probably the moisture content, but they're fairly close.

To get to them in the first place I just kept grinding finer and finer until I felt like the husks were too shredded and backed up a bit from there. I wind up with a mixture of flour, grits, cracked grains, and husks. Definitely not consistent like a proper mill, but it is effective.

Thanks Baron.

I'm going to try it your way.

davidkrau said:

Thanks Baron.

I'm going to try it your way.

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Let me know how it works out. After a few mashes you'll definitely begin to get an idea of what constitutes too fine of a grind, and what is too coarse.

I placed a washer on the wing nut side of the two clamping wing nuts. After tightning the wing nuts I used the centre adjustment to gradually fine tune my grind to what I figured was good by sight. Took a pound or less of grain but I get as good a crush as my LHBS gave me.

boo boo said:

I placed a washer on the wing nut side of the two clamping wing nuts. After tightning the wing nuts I used the centre adjustment to gradually fine tune my grind to what I figured was good by sight. Took a pound or less of grain but I get as good a crush as my LHBS gave me.

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I've had one of these mills new in the box for about five years now. I guess it is about time I started using it, so I just got it out and had a look. So if I'm reading you correctly, you put washers under both of the smaller wing nuts? Not between the two metal pieces they are clamping together? It seems like if you tighten the two wing nuts all the way down, that the crush would pretty much produce flour or grits. Any help would be appreciated...

Doesn't have anything to do with the grind, but on mine I took off the handle, and cut the head off a bolt. Then I threaded the bolt into the hole on the shaft instead of the handle. This let me clamp my drill on to it instead of cranking by hand. I'm lazy.

Lounge Lizzard, A thousand aploigies. You are right, the washers go between the two sections so the two peices are spaced out more than they were, then the single adjustment screw can be used to fine tune it.
Alemonkey, I grind by hand as I only do 5 gallon batches and <10 Lbs of grain isn't that much by hand.

Incidentally, the mill I received from Northern Tool came with two nylon spacers to insert on the bolts that hold the two grinding plates together...other mills I've seen didn't come with these and people usually insert metal washers there.

well, we had a corona for our first several batches, and eventually i got the best results by having a fairly loose setting and running the grist through twice. it looked pretty good that way. and then we got a three roller mill from crankenstein.

no comparison. the beer is definately better, the efficiency went up ten points. consider a better grinder.

MorBro said:

no comparison. the beer is definately better, the efficiency went up ten points. consider a better grinder.

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Just curious how the beer got better...

the beer got better. How?

maybe it was just luck.

maybe it was just experiance.

maybe it was a better crush resulting in less tannin extraction.

who knows?

what i do know is you can have my corona mill for ten bucks, plus shipping.

Tannin extraction is a function of pH and temperature, not grain crush. However, if I hadn't bought a Corona for $14 + shipping I'd probably jump on your offer!

MorBro said:

the beer got better. How?

maybe it was just luck.

maybe it was just experiance.

maybe it was a better crush resulting in less tannin extraction.

who knows?

what i do know is you can have my corona mill for ten bucks, plus shipping.

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ten bucks, huh? i sent you a PM.

Lou said:

ten bucks, huh? i sent you a PM.

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Get in line, pal.

I posted this in another thread, but here's a cheap one:
http://cgi.ebay.com/Heavy-Duty-Cast...454294488QQcategoryZ32882QQrdZ1QQcmdZViewItem

BTW, I tried setting my Corona for a very fine grind on my last batch. Somehow I gained about 10 points of efficiency. I have mixed feelings about that, because if I'm getting good efficiency I have less incentive to buy the Crankandstein I've been eyeing.

a finer crush will get you a better efficiency at the cost of making more flour. That may cause sparging problems and also a finer crush means more broken husk to deal with.

I knew a finer crush would get me more efficiency, but I was surprised that it helped that much.

It is likely that you have already noticed that the hopper included with your grain mill isn't worth a sh**. If you haven't figured it out yet, you'll need to fabricate a larger hopper to hold your grain bill. Why not do it all at once? see the hack job below.
And don't forget the threaded rod, and power drill. Nothing like power tools to make life easier!