Grain mill roller diameter effect

[kincade]

I've been reading today and wondering what effect grain mill roller diameter has on the crush. I know the primary effect is speed of crush, but what is the secondary effect on the quality of the crush?

For instance:

New Rebel Brewer mill (drool) has 1 5/16"" x 5" stainless rollers
Barley Crusher has 1.25" x 5" rollers
Monster Mill mm-2 has 1.5" by 6" rollers
Monster Mill mm-2-2.0 (drool) has 2" by 6" rollers

So, is there an appreciable difference between each? Or does it merely translate to the speed one is able to crush the grain?

 

[Wonka]

Excellent question. I've been wondering as well. Rebel Mill is on my short list.

 

[kincade]

I sent Fred at MM the same question and this was his response. Very interesting and makes perfect sense:

The larger rollers will feed down to a smaller gap than a smaller roller, and can produce more squish than shred, and can improve crush quality somewhat. You will find that the larger the diameter of the roller, the less aggressive the knurl needs to be to feed grain. So infinite diameter smooth rollers are the ultimate. Larger rollers also have more surface speed at a given rpms, for more throughput.

 

[kincade]

Spoke to Rebel Brewer today and they told me the diameter is actually 1 5/16" rather than 1" that they list in the original specs vendor thread. Corrected the original post.

 

[Bobby_M]

I honestly don't know why anyone would make a mill with smaller than 1.5" diameter rollers. The many problems people are having with the BC feeding is due to a slightly worn knurl. The larger the roller diameter, the more shallow the entry angle is for the grain. It gradually gets grabbed, then squeezed (that's what she said). Small diameters, if the grain ever catches, has to be ripped through by getting caught between two sharp knurls.

If I ever buy another mill it will be the MM2-2.0

 

[kincade]

I honestly don't know why anyone would make a mill with smaller than 1.5" diameter rollers. The many problems people are having with the BC feeding is due to a slightly worn knurl. The larger the roller diameter, the more shallow the entry angle is for the grain. It gradually gets grabbed, then squeezed (that's what she said). Small diameters, if the grain ever catches, has to be ripped through by getting caught between two sharp knurls.

If I ever buy another mill it will be the MM2-2.0

I agree 100% with what you are saying... I am wondering at what point is 'big enough'. Rebel Brewer did mention that their knurl is fairly aggressive (presumably to combat the smaller diameter).

Another factor to toss in here is this: From what research I've done the 303 stainless Rebel uses is equivalent in hardness to the 1144 steel that Monster uses, both of which are harder than the 1018 steel that Barley Crusher uses. So both should wear quite a bit longer than the BC.

 

[Bobby_M]

I would say that if cost is a concern, the MM2 with 1/2" drive upgrade would put you close to the rebel price.

 

[kincade]

I would say that if cost is a concern, the MM2 with 1/2" drive upgrade would put you close to the rebel price.

Yep, they are very close, within about $10 of each other after shipping. One has a larger roller, the other has stainless. It's nice having all these options from which to make a purchase!

 

[samc]

For me as an unhappy BC owner, the Rebel mill is tempting but has no long term track record. MM is a known machine. I wait !

 

[BBL_Brewer]

While we're talking options, what is everyone's take on hardened vs not. I'm in the market for a new mill myself. I seriously considered the rebel mill, but then I started comparing to crankenstien/monster and have pretty much decided that monster sounds like the better mill. Still not sure whether I want the MM2-2.0 or the MM3-2.0. I'm leaning towards the MM2-2.0 because of the larger gap adjustment range, but I don't know whether to upgrade to hardened or not.

Sorry for the hijack OP, I just didn't want to start a new thread.

 

[passedpawn]

For me as an unhappy BC owner, the Rebel mill is tempting but has no long term track record. MM is a known machine. I wait !

My brother in Cali bought a BC. I got to use it last week. It got the job done, but I was surprised how small it was compared to my old JSP malt mill. The hopper was nice, though.

 

[microbusbrewery]

While we're talking options, what is everyone's take on hardened vs not. I'm in the market for a new mill myself. I seriously considered the rebel mill, but then I started comparing to crankenstien/monster and have pretty much decided that monster sounds like the better mill. Still not sure whether I want the MM2-2.0 or the MM3-2.0. I'm leaning towards the MM2-2.0 because of the larger gap adjustment range, but I don't know whether to upgrade to hardened or not.

Sorry for the hijack OP, I just didn't want to start a new thread.

I got the Crank and Stein 2D recently and it's pretty sweet. Seems really well made.

Re hardened rollers, if it's in the budget no harm in getting it. That said, I doubt it's really necessary on a homebrew scale. I think it's more practical for a homebrew shop where it is being used throughout the day, every day .

 

[FredTheNuke]

I'm lost on the "problems" with the BC. I have put hundreds of pounds through mine with no issues at all - all left at factory adjustments. I blow it clean with compressed air every once in awhile and crush on. I hit my Beersmith 2 O.G. with BrewHouse Eff in the high 70's... Are we splitting hairs here or are other BC owners having issues I'm not yet aware of?

 

[MNDan]

My BC stopped pulling grain through due to worn rollers - I've got a MM2-2.0 now. Oh, baby!

In the BC's defense, it worked fine for 7 years or so and I brew around 160 gallons a year. Not bad, but I think my Monster is gonna last way longer - the rollers look much nicer & just the size of the rollers alone should help.