I did a grind test just to demonstrate how the Super Jolly and Kony grind.

The Super Jolly grinds pretty fast. That speed discharges the grinds at a higher velocity than most home grinders. That added velocity helps prevents clumping.

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The Super Jolly ground 27 grams of coffee with an appropriate espresso grind setting. Of the 27 grams ground 25 were discharged in the hopper and 2 grams remained in the discharge chute.

The Kony grinds slower than the Super Jolly and does produce slightly more clumps because of that. However those clumps breakup easily when the doser is worked. The Kony suffers from popcorning. For those that are not familiar with the term, popcorning is when the coffee beans pop up in the entry to the grind chamber as the hopper empties, essentially popping up like popcorn. You can hear the popping about half way through the video:

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Unfortunately, for the Kony, popcorning changes the grind. If you keep your beans in a separate container and only dose what is needed per shot, the grind's uniformity will suffer. The Kony likes to have a partially full hopper so there's pressure to keep the feed of beans steady. Without it, the grind changes as the bean supply is depleted.

The Kony ground 34 grams of coffee with an appropriate espresso grind setting. Of the 34 grams ground 31 were discharged in the hopper and 3 grams remained in the discharge chute.

Why the odd weights you ask, that is simply what I had in the grinder throat when I ran the video.

gscace wrote: I presume that there are other reasons as to why speed is kept low with conicals besides heat. I'm guessing that low speed increases cutter life.

-Greg

Maybe the slower rotational speed increases uniformity in both partial size and practical shape? That is something we may be able to answer thanks to John's resources.

Ken Fox wrote:I want to make one point that I think is pretty obvious but should be directly addressed. Heat from grinder burrs is possibly an important issue in a HIGH VOLUME SETTING but probably not to us HOME users. If your normal practice is to grind coffee for 1 or 2 shots at a time, separated by a period of non-use, it is debatable or maybe JUST PLAIN SILLY to claim that there is any benefit from a conical grinder, in a home setting, in this regard.

300 or 400 rpm (with less resultant heat production) may be important, but in a home setting I think this is in serious risk of setting off my BS meter.

There may (or may not) be inherent benefits from conical burrs and their grind products vs. planar burrs. If these benefits or differences are "real," I am highly doubtful that they come from reduced heat generation of any grinder in a low volume home setting.

ken

In a home setting I would agree, heat transfer to the coffee while grinding is not an issue. I still plan on trying to plot a temperature or two with the Fluke, even if it is for no reason than my own curiosity.

I wonder if ceramic burrs would provide better heat control in a commercial environment, I know LM uses them in the Swift. Besides out-boarding the motor and going to a belt drive to prevent motor heat transfer, I do not think there is much more that can be done. Grinding by itself will produce heat from friction. Teflon or other non stick, friction reducing coating would probably not survive long on a cutting burr. I wonder what carbide burrs would be like.

cannonfodder wrote:Maybe the slower rotational speed increases uniformity in both partial size and practical shape? That is something we may be able to answer thanks to John's resources.

I had a conversation about the mechanics of conical vs. planar grinders yesterday with Rick "Javaman" Knowlan of Vancouver, with whom I spent an enjoyable day, first on a cafe crawl and later with dinner at his house including his charming wife, Mary. Rick was originally educated as an engineer, although he works now in strategic planning.

From our conversation it appears highly doubtful that these different grinder types were originally developed for reasons of perceived grind quality differences, rather before the development of electrical motors, it would have been difficult to produce enough torque by hand to operate a planar grinder. Subsequent development of these grinder types, until perhaps very recently, was done for reasons other than grind quality issues, although this may play a part in the last few years.

Online coffee has greatly accelerated the pace of development and comparison of coffee equipment, but at the same time can serve as a mechanism for the propagation of unfounded rumors and impressions that will not stand up to scientific examination. I for one hope that there is more to the conical vs. planar grinder discussion than a whole bunch of otherwise fully respectable people being too easily convinced of the wisdom of their own observations, which coincidentally mirror the published observations of others but that have also not been subject to real scrutiny.

Getting back to our Vancouver cafe crawl, Rick and I visited 4 of the better Vancouver cafes which included Re-entry, a new cafe anxious to please but still working out some of the early kinks of a 6-month old establishment, the new Artigiano in West Vancouver, worthy of a visit if for no other reason than to view the surrounding high end shopping center, Brazza in North Vancouver, and of course, the Elysian Room. The "best" by far was (no surprise here) Alistair Durie's Elysian Room on 5th and Burrard, with Brazza putting in a very respectable 2nd place showing. For atmosphere and espresso quality, the Elysian room is the standout choice in Vancouver and has been on my prior visits as well.

While at the Elysian Room, Rick and I had an extended conversation with Alistair which included the topic of grinder types. His opinion, which I hope I am not misquoting, was that one can't talk generically about "conicals" and "planar grinders" but rather about SPECIFIC grinders. He gave me the distinct impression that in his cafe there is a preference for the Anfim planar grinder over their Robur.

This TGP piece is very useful and provides a lot of good descriptive information. I fear that in the final analysis it is going to be necessary for some sort of blind tasting comparison to be done to settle, once and hopefully for all, whether conical grinders truly make "better" espresso than do planar grinders.

ken

Ken Fox wrote: This TGP piece is very useful and provides a lot of good descriptive information. I fear that in the final analysis it is going to be necessary for some sort of blind tasting comparison to be done to settle, once and hopefully for all, whether conical grinders truly make "better" espresso than do planar grinders.

ken

That is also in the works. Jim Schulman, our resident cupping expert, is the last stop for all the grinders. He is planning on a blind side by side cupping. We are also planning something similar with espresso shots although a side by side is not really possible unless you have two identical machines (which Jim also has in his espresso mad scientist lab). I was planning on a more informal, have the wife grind some samples into a container and I then prepare the shot and sample it to see if I can pick out which grinder it came from.

I went into the test a skeptic, is all the hype justified and how do we prove/disprove the common dogma on the web. My perceptual testing, yes there is most definitely a difference. I won't say one is better than the other, but simply that they are different. Each type producing a cup that accentuates different flavors but the test is still in its infancy. I am very interested in seeing if there is a difference between the Kony and Robur.

Hopefully when this project is all over, we will have some real, measurable data to help shed some light on the subject.

I think conclusions get stronger if we all do taste tests of various sorts. Rigor is a good thing, but it can only be had by narrowing down to very tight set of conditions. If everyone does some sort of test (I like the blind basket thing -- and would love to see everyone make a pair of shots in succession rather than just one, whenever they feel like an espresso, sip on them both, see if they like one more, and keep a log), we'll get a feel for how well anything that turns up in cupping or measured particle distributions holds up in general use.

Ken Fox wrote:before the development of electrical motors, it would have been difficult to produce enough torque by hand to operate a planar grinder.

I have been under the impression that you actually need less torque to turn planar burrs due to their smaller cutting area (compared to conical burrs of equal size)? But one would need either larger burrs or higher rpm to achieve the same output volume from planar burrs?

cannonfodder wrote:Hopefully when this project is all over, we will have some real, measurable data to help shed some light on the subject.

Yes, indeed. I look forward to this.

Br,
Teme

Ken Fox wrote: long story

Interesting post and I agree with you that the difference in taste might be coupled more to a specific grinder then that it is coupled to flat burr or conical. However true scientific research and research where all parameters are fixed except for the burrs itself is, at least for now, not attainable given money, time, available machines (although SuperJolly and Kony come close) etc.

In that respect I truly believe that the way testing is done on HB and some other sites is already on quite a high level, especially since most are volunteers and enthusiasts without real labs donating spare time etc.

At the end of the day I think this test will learn me, coupled with the other grinder tests already done, a lot to help me decide which grinder is most suitable to my taste of coffee. Nevertheless it would be nice if a more definite conclusion about flat vs conical burrs could be reached!

The blind testing by Jim is an excellent way to end this test. Maybe he could even throw in his Versalab grinder as well to make the comparison complete. Oh wait, thats not true, I also would have liked the new Elektra and the Compak K-10 to be included.

Well, we can't have everything so maybe that will be dealt with in a later test....

AndyS wrote:The difference is, labs probably arrange things so that they can open the cabinet doors.

Put the kit in front of the open door, I haven't quite figured out why I have doors, now... My two group wouldn't let me open the cabinets above (behind?) it, so I just opened them and put the machine in there as a doorstop! I remember wanting a Robur, too. Right up until I unboxed one for the AZ Barista Jam. I had just ridden one of my Majors over to the Coffee Vein in the front seat of my bittly lil red truck (Mazda B2K). I fell in love with my Majors right then.

cannonfodder wrote:My perceptual testing, yes there is most definitely a difference. I won't say one is better than the other, but simply that they are different. Each type producing a cup that accentuates different flavors but the test is still in its infancy. I am very interested in seeing if there is a difference between the Kony and Robur.

Hopefully when this project is all over, we will have some real, measurable data to help shed some light on the subject.

This would seem to sum up the evidence to date in favour of conical burrs over flat burrs.

Looking forward to the "evidence" at the end of all of this. These kinds of things always get you "thinking" you need something new which you were perfectly happy without before you got online.