Are rollers better than burrs?

#1: Post by **DamianWarS** » April 26th, 2020, 11:52 am

industrial mills are roller based and they apparently are far superior to burrs so why is this the first I've heard of them? do they make bar top/cafe roller mills? The direction of uber even grind size and higher extractions in specialty makes me wonder why roller mills haven't been adapted into this space.

#2: Post by **jja619** » April 26th, 2020, 12:35 pm

I haven't researched it much, but I think they don't come in bar top sizes. Not sure what limitations there are to scaling them down.

#3: Post by **wachuko** » April 26th, 2020, 12:42 pm

Interesting...

From here: https://www.mpechicago.com/coffee-grind ... hnologies/

#4: Post by **ira** » April 26th, 2020, 12:50 pm

They are certainly not currently made in bar top sizes and I think there's a limit to how small a diameter the rollers need to be and the fact that you need at least 2 sets of rollers, possibly three for what we' be interested in. I did talk with someone about this at an SCA show one year and as I recall and it's fuzzy at best, it's probably $10,000 to $20,000 for a small roller grinder that would not likely be small enough to be useful. I think roller grinders are transitioned to when you need their throughput, not so much for uniformity.

Ira

April 26th, 2020, 1:14 pm

I think this was discussed back in 2013 here at HB - Roller Mill Grinder

#6: Post by **another_jim** » April 26th, 2020, 5:09 pm

In some deep recess in some lost storage closet I have a hand crank roller mill designed for grain grinding (survivalists are very picky about the uniformity of their ground grain). It requires two passes with a gap adjustment between passes. My experimenter's sitzfleisch was not equal to the task of testing it properly; but the dozen or so shots and brews I did try gave no great reason for hope.

#7: Post by **yakster** » April 26th, 2020, 5:18 pm

You might be able to rent a roller mill at a home-brew shop for testing.

April 27th, 2020, 5:05 am

ira wrote:They are certainly not currently made in bar top sizes and I think there's a limit to how small a diameter the rollers need to be and the fact that you need at least 2 sets of rollers, possibly three for what we' be interested in. I did talk with someone about this at an SCA show one year and as I recall and it's fuzzy at best, it's probably $10,000 to $20,000 for a small roller grinder that would not likely be small enough to be useful. I think roller grinders are transitioned to when you need their throughput, not so much for uniformity.

Ira

Makes you wonder why no one's trying to adapted them to bar size. With all the kickstarter gimmicks of coffee you would think rollers would enter this space.

I gather the larger the roller the more surface area comes in contact with the bean, the crushing power would be increase and for longer periods where it would possibly have diminishing returns the smaller the roller is. There may be a point where a very small roller would just make a mess and a very large roller would accomplish greater consistency. Perhaps a blond roast would be less effective and it may just flatten but not crush being more effective when the beans are brittle (more roasted). So they might be more suited to darker roasts... but I'm just guessing.

This might be consistent with industrial rollers as they are meant to produce large amounts of coffee for and I would think the demand would be higher with grocery store brands or pod coffee which generally are darker but not really for speciality where you get smaller batches. Does a cafe even have the sort of demand to justify a large industrial size roller mill or an order from one?

3 rollers seems to be common in the big ones, maybe a bar top machine with 10 small rollers could accomplish similar results?

#9: Post by **bakafish** » April 27th, 2020, 5:11 am

Maybe this is the smallest roller mill.
http://www.inoue-seisakujo.jp/products/05se/05se.html
JPY 2,200,000. More than US$ 20,500.

#10: Post by **bettysnephew** » April 27th, 2020, 10:55 am

The reality of roller mills for actual home use is likely a fantasy, particularly for single dosing. I was in industrial maintenance in the packaged food industry (flake breakfast cereal) for some years. The diameter of the rolls needed to break particles the size of coffee beans would make for for quite a large and very heavy high inertia machine which would require a lot of power to put in motion and sustain speed. Large diameter rolls would be required to keep the beans from skipping away from the gap or just sliding around above the gap and not breaking. Oh and by the way this is an extremely noisy operation. The multi roll machines for commercial use reflect this, the first roller would have a fairly wide gap to be able to split the bean and each successive roller has a narrower gap to reach the desired fineness of the finished product. Also there is the long term issue regarding maintenance of the rollers as they need to be ground to resurface the faces as the breaking process really takes a toll on the surface finish. The surface has to be rough enough to have a bite to pull the product through the gap but smooth enough to be consistent in the gap that the finished product is of a specific granular size. There are a few coatings that can be applied to the rolls that make the surface last somewhat longer but then you get into issues of metallic flaking into the product when the coating begins to fail. I do not see even the wildest and well heeled HB finding this to be a practical endeavor. If a person had enough wealth to consider this route it would probably be more cost efficient to have small quantities custom milled and packaged in small packages for day to day use.