Minimizing Waste and Static on Large Commercial Grinders

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michaelbenis

#1: Post by michaelbenis »

How much of this tons of waste is there on the Roburs, compared to the Kony or the big flat Mazzers (Major) or SJ?

Are you talking about what gets left between the burrs Nicholas?

Cheers

Mike


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LMWDP No. 237

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shadowfax

#2: Post by shadowfax »

Michael, the Robur E has a huge grind path due to the addition of the augur atop the burr set. If it spun at low RPMs, I imagine it might feed the burrs whole beans, but as it is it seems to cut them into smaller pieces before they load into the burrs. As near as I can tell, that adds to the Robur's already large path of smashed-up beans, although at least those particles between the augur and the burrs aren't fully ground. Add that problem to a covered chute that basically ensures that the grinding chamber and the chute are always full and a bit of a pain to clear out, and you have a difficult-to clean grind path that retains a lot of ground coffee when the hopper is charged and you've pulled a shot or two; 30-40g is probably a reasonable guess.

Then there's another problem that I've been thinking about lately, considering modding my own Robur to doserless. The chute is so large, and the grind chamber as well, that I don't know that the the path of the ground coffee into the funnel/hopper is even remotely a FIFO (First In First Out) queue. It looks like, under many circumstances, only a portion of the chute has moving coffee, meaning that, even though you might only have a small amount of stale coffee in the system, purging it by simply grinding more fresh coffee is potentially not going to work or require you to waste much more coffee than just the stale coffee that you're trying to get rid of. So, I've been thinking about shrinking my Robur's chute somehow to see if that will make it waste less coffee and create less static. My fear, of course, is that it will slow it down a lot and retain a lot more coffee.
Nicholas Lundgaard

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michaelbenis (original poster)

#3: Post by michaelbenis (original poster) »

Many thanks for that detailed reply. I've never seen a Robur.

Can you not uncover the chute, or is not a simple matter of removing a guard as on the SJ?

Plumbing pipe inserted in the grind chamber might reduce the inside diameter without introducing non-food grade materials. Or - if you find a glass jar the of the right diameter, you could cut off the bottom and leave the top as a small screw-on hopper lid. I'm just thinking aloud here. Absolutely no experience with either of these ideas.

Cheers

Mike
LMWDP No. 237

Theodore

#4: Post by Theodore »

shadowfax wrote:Michael, the Robur E has a huge grind path due to the addition of the augur atop the burr set. If it spun at low RPMs, I imagine it might feed the burrs whole beans, but as it is it seems to cut them into smaller pieces before they load into the burrs. As near as I can tell, that adds to the Robur's already large path of smashed-up beans, although at least those particles between the augur and the burrs aren't fully ground. Add that problem to a covered chute that basically ensures that the grinding chamber and the chute are always full and a bit of a pain to clear out, and you have a difficult-to clean grind path that retains a lot of ground coffee when the hopper is charged and you've pulled a shot or two; 30-40g is probably a reasonable guess.

Then there's another problem that I've been thinking about lately, considering modding my own Robur to doserless. The chute is so large, and the grind chamber as well, that I don't know that the the path of the ground coffee into the funnel/hopper is even remotely a FIFO (First In First Out) queue. It looks like, under many circumstances, only a portion of the chute has moving coffee, meaning that, even though you might only have a small amount of stale coffee in the system, purging it by simply grinding more fresh coffee is potentially not going to work or require you to waste much more coffee than just the stale coffee that you're trying to get rid of. So, I've been thinking about shrinking my Robur's chute somehow to see if that will make it waste less coffee and create less static. My fear, of course, is that it will slow it down a lot and retain a lot more coffee.
It is for having less stale coffee,that I have bought Nino,as they insist,that it has very small amount of remaining coffee.
Espresso uber alles.

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shadowfax

#5: Post by shadowfax »

michaelbenis wrote:Many thanks for that detailed reply. I've never seen a Robur.

Can you not uncover the chute, or is not a simple matter of removing a guard as on the SJ?

Plumbing pipe inserted in the grind chamber might reduce the inside diameter without introducing non-food grade materials. Or - if you find a glass jar the of the right diameter, you could cut off the bottom and leave the top as a small screw-on hopper lid. I'm just thinking aloud here. Absolutely no experience with either of these ideas.
The Robur looks just like a Super Jolly, except the hopper is a couple of inches taller, and the chute is much wider (as is, obviously, the grind chamber). The chute is also positioned somewhat to the right of the grind chamber, making the coffee exit tangentially rather than radially:


The Robur's huge grind chamber (via my Flickr) - Note where the chute is.


Detail of the exit chute (via my Flickr) - It actually widens somewhat toward the exit side (where it opens into the doser chamber).

Anyway, my "doserless" conversion would involve a Robur E funnel which has just become available at some expense ($230 IIRC), and then something to deal with the static on exit that doesn't involve rendering the chute inaccessible. This could be mounting a static screen on the lid (so it comes off when you take the lid off, for cleaning), or it might mean that I get an aluminum block milled precisely to block off about 80% of the exit chute (pictured above).
Nicholas Lundgaard

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networkcrasher

#6: Post by networkcrasher »

shadowfax wrote:This could be mounting a static screen on the lid (so it comes off when you take the lid off, for cleaning), or it might mean that I get an aluminum block milled precisely to block off about 80% of the exit chute (pictured above).
This is what I did, and it works just fine. Basically the arrangement is funnel, grid, sticky foam sheet (stuck to the funnel), then grinder body.

The other cool thing is if one drills a larger hole underneath the holes that the screws go through to attach the funnel to the grinder, you can just a) leave the screws loose, or b) tighten up the screws, then slightly loosen said screws and slide the funnel up and off the screw heads, making the throat easy to clean.

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dsc

#7: Post by dsc »

Hi guys,

something I already mentioned to Nicholas, but I might as well say it hear, you will probably have a lot of problems with static when using the removable grid. At least I did when I was still reluctant to use the permanent grid.

Regards,
dsc.

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shadowfax

#8: Post by shadowfax »

Indeed, a lot of my comments stem from a prior discussion with Tom. Tom's suggestion (and it definitely matches my experience) is that the static grid doesn't prevent static unless the chute is totally full. When it's filling up, the static is just as bad as with no screen.

That's led me to consider a door on the chute that keeps it closed until full, and then allows coffee to extrude out the bottom after it fills up (again, the door would have to come off with the lid or something so that you could sweep out per-shot or per-session or per-adjustment), or, as I suggested earlier, shrinking the chute by a great deal.
Nicholas Lundgaard

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michaelbenis (original poster)

#9: Post by michaelbenis (original poster) »

Ah! Many thanks for those photos, Nicholas. Makes what you were saying much clearer.

Considering the potential static/clumping problems and the clean sweep you're getting with your doser (seen on Flickr) vs. the comparatively massive amount of grinds retained in the chamber and chute, I'm curious why you want to go doserless.....

Cheers

Mike
LMWDP No. 237

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shadowfax

#10: Post by shadowfax »

Mike, good observations--the doser has a lot going for it--it lets you dose evenly into the portafilter, and it holds the coffee so that you can do partial dosing/mid-dose grooming, that type of thing. It's also reasonably easy to clean out.

On the other hand, the doser is noisy if you use it right, and it's kind of a pain to sweep out properly (thoroughly) in terms of cleaning off the tops of the vanes and the static grounds that pepper the side walls of the doser.

I'm a dosered advocate because in my mind the doser gives the best results with the least waste and mess; that said, I am very tempted by the prospect of a doserless system that has no static issues with an easy way to minimize waste (i.e. full chute access). In my mind, I'd be really happy if dosing could be as simple and quiet as pushing a button, popping the lid, and sweeping out the chute with one or two strokes. You know, minus the thwack thwack thwack, and then the chute sweep, and then the vane sweep, and more thwack thwack thwack....

In all honesty, Theodore is right--I should have gotten the Nino. :mrgreen:
Nicholas Lundgaard