What sort of mill?

 

The best advice I can give you is to keep your mill clean. Gunk can build up in the knurling on the rollers and decrease its ability to pull the grain through.

 

If it's a two roller, they work well. Three roller is nicer, but you get the same results from a two roll with two passes rather than one pass.

The European malts tend to be plumper and larger, so the mill gap needs to be opened up more than when milling North American malt. The malt from North America can be milled on the standard setting on my Grain Crusher mill. When I mill Wyermann or Crisp Maris Otter, the mill will stop passing grain after a while because the grains are too big, so I open the gap slightly more the first pass and pass the grain a second time with the standard gap or maybe even slightly smaller than standard gap. The is effectively what a three roller does with one pass. The first gap a lager than the the second gap.

P.S. Watch out for those nasty stones, especially in European malts, they can do damage to the mill. I go slow with those malts so if a hit a stone it doesn't do any damage. I have never seen them in any of Rahr's malts.

 

Having a grain mill is great for consistency and dialing in mash efficiency. I’m not a metric guy (they tried to hammer that into our heads in grade school, but it didn’t stick for me) so I set my mill at 32 thousandths of an inch with a feeler gauge. You might want to try .035” at first. I run mine with a 1/2” variable speed drill. At first I had it screwed into the top shelf of a 4’ gorilla shelf but didn’t take long to figure out it’s better to bolt it to the top shelf with a 5 gallon bucket below. One of the best brewing purchases I made! Hope this helps. Cheers

 

Honestly, I would assume that the marked settings are not very accurate and I would set the gap without paying any attention to them. When I set up my mill, I set the gap to the thickness of credit card, and over the next few brews I played with opening and closing that gap by a few thou until I arrived at a setting that gave me a level of efficiency I was happy with along with a sparge that never gets stuck.

 

The best way to determine the effectiveness of the crush is to brew with it. The finer the better if your system can handle it without stuck sparges. Just go for it and adjust on the next batch. It’s not rocket science, that’s too easy.

 

Start there, finer will give better efficiency, more coarse flows better. Just watch your grain type and how the mill handles it. There is more than one way to skin a cat and it may take a while to dial it in. But don’t worry, you soon will be an expert on your mill.

 

And don't get hung up on getting the best efficiency numbers. Early on I was able to get 93% efficiency, but my sparges were often slow and a stuck sparge wasn't uncommon. I now don't crush quite as fine and get a consistent 75% and no worries about my run off. Sure, I use a bit more grain, but I buy in bulk so I am only paying 70 cents a pound for base malt, I consider this a small price to pay for a brew day that is more fun and stress free. As a bonus, I find my beer also tastes better at 75% than it did at 93%.

 

You're going to definitely want finer than .050". I do recirc and have no problem with .035" setting. Different malts do better with finer or courser crush, but for general use, the .035" or so should give good results.
Get some feeler gauges. Those markings won't mean anything.

 

I recently got a new grain mill and set the gap to about .03". My brewhouse efficiency has jumped up about 8%. My best purchase in a while....

 

Good purchase on the grain mill. I use an electric drill at slow speed to drive mine.

I run a fairly fine crush, but I use a modified BIAB method and don't worry about stuck sparges. I have heard if you grind more finely, you might want to add rice hulls to help the sparge. I'm not sure how well this works, so maybe someone else can chime in.

 

I have done that, it usually not necessary unless you use adjuncts like rice, rye or oatmeal. But if your worried, 4 ounces per 8-10 pounds can work wonders.

 

I use a brew bag in my mash tun rather than rice hulls or whatever. I use a corona mill and basically turn my grain into flour. I set the mill gap 2 years ago and haven't looked at it since, the grain comes out the same and my efficiency hasn't change so I haven't worried about it. I sometimes look at a roller mill since they look cool, but really anything will do the job.

 

I have a three-roller MonsterMill, and I set it at .05 (1.2 mm). (I almost exclusively use European malts, and I actually could have used a coarser setting, but then the wheat malt kernels wouldn't be crushed efficiently.)

I'd go against the advice to mill as fine as you can. That will result in shredded husks, and that means more tannin extraction. It may also cause lautering problems if you fly sparge.

I batch sparge, and I get a mash efficiency of 82/83% when brewing beers with an OG in the 1.045-1.050 range, which I mostly do. Efficiency of course goes down when using more malt to brew stronger beers. (I could easily get 2-4% more if I wanted to maximize the yield, but I don't.)

As long as you set the gap close enough so that all the kernels get crushed, you don't need to mill finer. You might perhaps get one or two percent higher yield, but is that important?

Coarser particles means it'll take some more time to solubilize the starch, so that the enzymes can get to work converting it to sugars. Just take that into account, and your yield will suffer very little.

 

I literally powder my grain and I've got a bunch of medals from competitions so I suspect tannin extraction is not the issue people present it as.

Edit: However I doubt there is any real value to what I'm doing beyond the fact it works for me and I don't care enough to change it.