I'm thinking of improving the whole grinder concept, and so far I've come up with these "improvements" to help combat some of the problems people seem to be having.

- Hopperless grinder, with an automatic feeder that weighs the coffee beens and then doses set amount into the grinder, onto which a spring-loaded plate flips on to help feed the beans into the grinder.

- Automatic doser agitator, basically it waits for the grinder to finish it's job, then starts agitating the grinds to break any clumps, without dumping them out of the doser.

- "Perfect" distributor. This would be a little cavity between the doser and the PF where all the grinds are dumped after de-clumping, and then ejected into the PF. The chamber would be round and have the same dimensions as a filter basket, only slightly taller and maybe a tad smaller, with optional inserts to match smaller than 58mm PF's. This way all the grinds get distributed evenly into the filter.

What I'm still working on is the way everything interconnects and how to dump the grinds into the PF in an even manner...

Any other ideas? Comments?

Your "automated doser agitator" may cause uneven distribution of the grinds.

I have a hypothesis based pretty much on nothing about why constant thwacking of the doser lever while grinding usually yields better shots.

The Hypothesis: The coffee grinded and ejected from the burrs are not of identical or uniforms shape and density. By thwacking the doser lever continuously while grinding the grounds dumped into the filter basket are a more uniform mixture. The nature of this mixture is determined by the burrs, grinder rpm and other elements (eg. Popcorning if it is even important). This results in a more uniform mixture of all the different shapes and densities of the ground coffee in your filter basket.

If the above has any grounds in the truth or reality of pulling espresso then it would be a bad thing to agitate the grinds after completing the grinding process in any way allowing different shaped/density to separate from the "uniform" mixture created by the grinder. Agitation could result in separation.

Continuous lever thwackings only real benefit maybe to reduce clumping, but maybe it has another benefit.

narc wrote:Continuous lever thwackings only real benefit maybe to reduce clumping, but maybe it has another benefit.

Annoying the guests?

See the La Marzocco Swift for a new "type" of grinder... If only we could get it scaled down to single doses

Hi,

Having now used the M3 for several months, I'd suggest that its basic concept forms a good starting point. I'd add a feed augur of the sort that's on the new Roburs to avoid popcorning. Another problem the M3 has is noise: because the funnel is open and the whole structure is metal, it's quite noisy when grinding at five AM. Careful materials selection is a must, since it turns out that ground coffee is damned sticky stuff between static and oils.

But the size of the M3 is far more appropriate for a home setting than any other grinder of equivalent grind quality, and the ability to switch coffees and grinds with no waste or carry-over to speak of (about a third of a gram, the times I've measured it) are highly desirable for at least some of us in a home setting.

Best,
David

cafeIKE wrote:Annoying the guests?

See the La Marzocco Swift for a new "type" of grinder... If only we could get it scaled down to single doses

The only problem with that one is that it's bloody expensive, it does something completely unnecessary (tamping), and it's huge.

I was actually thinking of the M3 design. How does the burrs look on it?

Hi,

A couple of comments regarding your ideas:

- Hopperless grinder, with an automatic feeder that weighs the coffee beens and then doses set amount into the grinder, onto which a spring-loaded plate flips on to help feed the beans into the grinder.

How are you planning to weigh the beans? using a built in digital scale? maybe some other way (I'm pretty sure you can use some horizontal scanning to 'count' the beans/grinds and weigh it like that, but with various coffees it will probably fail). I think that the reason why all timer based grinders use volume based dosing is simply because it's too complicated and/or expensive to do it otherwise.

- Automatic doser agitator, basically it waits for the grinder to finish it's job, then starts agitating the grinds to break any clumps, without dumping them out of the doser.

As previously mentioned it probably won't work and will cause more bad than good. The reason for this is it will more the finer grinds to the bottom and the coarser ones will stay at the top. I'm pretty sure that grinders spill out a mixture of both constantly, so it doesn't separate before the shot.

- "Perfect" distributor. This would be a little cavity between the doser and the PF where all the grinds are dumped after de-clumping, and then ejected into the PF. The chamber would be round and have the same dimensions as a filter basket, only slightly taller and maybe a tad smaller, with optional inserts to match smaller than 58mm PF's. This way all the grinds get distributed evenly into the filter.

I thought about this a while ago when working on the Mazzer funnel conversion, but in the end I dropped it (I went with Brad's design). After a few months and working with Brad's funnels I'm happy it wasn't done like that as the coffee exists the funnel mostly at one point and the 'stream' of grounds is pretty narrow. This means you can move your PF around and fill the basket evenly. With a 'perfect' distributor it would have been dumped into one place and probably favour one side, creating an uneven distribution.

It would be a good idea to produce a grinder which has the outlet directly under the burrs, the same way it's done on the Versalab, but even then there's a problem with even distribution as the grounds are being pushed to the sides and you end up with a hole in the middle.

Regards,
dsc.

DavidMLewis wrote:Hi,

Having now used the M3 for several months, I'd suggest that its basic concept forms a good starting point. I'd add a feed augur of the sort that's on the new Roburs to avoid popcorning. Another problem the M3 has is noise: because the funnel is open and the whole structure is metal, it's quite noisy when grinding at five AM. Careful materials selection is a must, since it turns out that ground coffee is damned sticky stuff between static and oils.

But the size of the M3 is far more appropriate for a home setting than any other grinder of equivalent grind quality, and the ability to switch coffees and grinds with no waste or carry-over to speak of (about a third of a gram, the times I've measured it) are highly desirable for at least some of us in a home setting.

Best,
David

Yes, but as I have read, reliability, is not the best, especially for a customer living far away.It is not easy, to send it back from Greece for service a couple of days after the purchase.Is it?

The idea would be to use something like an digital scale to weigh the beans and them dump them into the grinder, probably by feeding them into a weighing chamber with a screw.

The agitator would work similarly to the twacking motion most pros use, only automated and cushioned to reduce wear. The small funnel idea is quite intriguing, maybe that coupled by another "agitator", this time something like a fast spinning feeder screw to improve flow and even out the flow, and an opening about 20 mm in diameter would give an improved distribution, providing that you move the portafilter around. This should not be a problem if the grinder is geared towards the anally retentive home barista.

I also have an idea of reducing the height of the doser, since it does not have to hold a lot of grinds, only break up clumps.

Overall these changes would benefit from being retro-fittable to most high end grinders like the Macap M4 or any mazzer, provided that they have enough room between the grinder exit and the doser exit, but it should not be a problem since the doser would be reduced to half it's height or more.

Theodore wrote:Yes, but as I have read, reliability, is not the best, especially for a customer living far away.It is not easy, to send it back from Greece for service a couple of days after the purchase.Is it?

From what I've seen the design isn't the worlds smartest. I've never seen one in person, but from what I can gather it's belt driven for some obscure reason (which means that the belt, at some point, has to be replaced, if it isn't made out of foreverlastium. It is also uncovered, which is a potential danger, belts can cut of fingers if the motor driving it is powerful enough) and I can't see why they didn't make a hopper for it, it must be a PITA to make sure the beans stay the small cavity above the burrs while grinding.

Still, I'm sure it's an excellent grinder, and these are just my observations, they might be just hot air.

Theodore wrote:Yes, but as I have read, reliability [of the M3] is not the best, especially for a customer living far away.It is not easy, to send it back from Greece for service a couple of days after the purchase.Is it?

That's why I said to use the ideas as a starting point. I was merely suggesting areas in which I find the concept might be improved. I would never recommend the M3 itself to anyone who wasn't both quite mechanically adept and patient, for instance an old Ferrari mechanic.

As to Stuggi's comments, there's actually nothing wrong with the belt that covering it and using a toothed one wouldn't cure. As it is it's well-enough shielded that getting fingers caught isn't an issue, but it is still exposed in an environment where eventual spills are likely. Not having a hopper, assuming the use of a Robur-like feed auger, is a good thing. It's what keeps bean bits from cooking between the burrs, and allows using the same grinder for different coffees throughout the day, which is highly desirable in a home setting if only to be able to have decaf at night.

Best,
David

Actually, de M3 has an agitator. Check the reviews and reports here.
And it is availiable with a hopper. A really smart design too.

The M3 maybe isn't such a good starting point tho'; It's very expensive. The cost isn't easy to bring down because the burr carrier is a solid piece of brass. Which is not cheap to manufacture. And certainly not to tight tolerances, which it is. And it has to be massive, to keep the burrs in place while grinding.
There are a few things that can be done I guess.
-Give the burr carrier two supports
-Two driving axle bearings.
-Flat burr set. The belt drive doesn't have to be that large, and the burr carrier can be smaller too.
-Cover the belt drive.
-Aluminum burr carrier. Cheaper than brass.

All this said and done, I still think there are significant improvements possible with standard grinders. Teflon coating on a straighter grind path would alleviate a lot of the current problems i think. Maybe an auger to prevent popcorning and a Versalab-type doser.

Stuggi wrote:I've never seen one in person, but from what I can gather it's belt driven for some obscure reason (which means that the belt, at some point, has to be replaced, if it isn't made out of foreverlastium. It is also uncovered, which is a potential danger, belts can cut of fingers if the motor driving it is powerful enough) and I can't see why they didn't make a hopper for it, it must be a PITA to make sure the beans stay the small cavity above the burrs while grinding.
they might be just hot air.

There are a lot of answers to those questions on the Versalab site. <http://www.versalab.com/server/coffee/grindernew.html> Shows your single dosing idea in practice (although, it's by volume, not weight) and allows for two apps, to use for two coffees, one dose at a time. The belt is so that it can easily accommodate a grind-through design, instead of the problems that burrs mounted on top of a motor with a side discharge can initiate. Cruise the site, follow the process, and a lot of the stuff that you're looking for is already there. If I could find someone interested in paying decent money for both of my Majors, I'd use the cash to buy me one o' these.

I'm very much a newbie, but from my understanding:

In theory, would it make sense to have a grinder that distributes grounds in repeated, impossibly thin, layers?

The idea here would be to create a "snowfall" action where grounds are dropped in consistent, thin layers from a high location, perhaps through a long vertical tube. It would be similar to the idea that if you want to salt food more evenly, you sprinkle it from high above, instead of close to the food, forming localized clumps. I sort of see this idea in the Marzocco Swift.

Rather than re-inventing the wheel...

It's worthwhile to check out what's been done in the past with coffee (from the Alinox through the Swift to the Serch-modified Anfim to the prototypes of the new LM grinder) -- but more importantly to look at what's been done in other industries, in particular in pharmaceuticals.

More than that, however, you probably should start with defining goals and objectives - 'cause right now it looks like you're focusing purely on "a better version" style approaches. For example... if a critical goal is to create very consistent grind size (and I'm NOT saying that would be a good thing) you would probably look at either two-stage grinding (like the Alinox) or vertical burr sets. Both of these have trade-offs, however, that might compromise your other goals (easy maintenance, easy adjustment across wide ranges, little to no trapped grounds for example).