Mazzer Kony Espresso Grinder Review
by Randy Glass - Copyright 2008 - All rights reserved

The Mazzer Kony Review
by Randy Glass - 4/1/2008

     If you have spent any time asking questions or perusing the various Internet coffee forums, one bit of advice that turns up everywhere: "The grinder is more important than the espresso machine." Espresso is the highest form of the coffee beverage, extracting every last bit of what the bean has to offer to the palate. For the best to be offered, the coffee has to be precisely ground. The size of the particles have to be within a narrow band of particle sizes, ground with the very minimum amount of dust, and with little or no static cling, and done as gently as possible so that the beans are not overheated so the flavor stays in the coffee. Finally, virtually all grinders designed to be used for espresso feature stepless adjustments so that you never find yourself wanting for an in-between grind setting.

     You have probably read the review linked below this one on the Espresso! My Espresso website in the list of review links, and so you are aware that I acquired a Vibiemme Domobar Super espresso machine in mid-2007. For about the first nine months with the Vibiemme I had been using my Rancilio Rocky coffee grinder. To put things into perspective, at around $300 the majority of coffee drinkers would be shocked at the cost of that grinder. Rocky's replacement burr set costs more than most people would pay for a grinder. The Rocky is an excellent grinder, and one that served my needs for just over seven years. While most of its shortcomings were easily dealt with, when it comes to espresso, one of its problems is that its adjustment steps are about 0.0015" (0.03mm) each. That may not sound like much, but that equals about five seconds of extraction time.

Although Rocky is a substantial grinder in its own right, next to the Kony from Mazzer it is dwarfed in stature

     I had been considering upgrading to a higher quality grinder, dedicated to use for espresso for sometime, and through Jim at I was able to purchase a used Mazzer Kony grinder. Mazzer is one of the premier manufacturers of coffee grinders— indeed, they actually manufacture burrs used by other companies. Selling at discount for about $1300, this is not your average grinder. The replacement burrs alone are $165!

Why so Expensive Just to Grind Coffee?
     The Mazzer Kony is designed for serious commercial use and so many of its features are aimed at high production and ease of maintenance.
  • If the power switch is left at the first stop, an internal switch on the doser lever restarts the grinder every 12 doses which are dispensed. There is a flap over the exit chute from the grinding chamber that senses when the ground coffee in the doser reaches a certain height and turns off the grinder. There is a second momentary position of the switch that turns the grinder on and leaves it on even if the switch is released, at least until the doser is filled. Otherwise, just turn the switch to the full-off position to stop the grinder.
  • The doser has a small mechanical, digital counter to show how much coffee has been dispensed. The counter assumes that you have properly adjusted the doser so that one click equals one dose. For home use it is worthless, if that.
  • The doser vanes are easily adjustable so that each click of the lever will dispense between 5.5 and 8 grams of coffee. This is done by having the doser vanes telescope upwards so that by loosening the center nut on the doser vane they become taller.
  • The bean hopper, at nine inches tall and eight inches across, holds pounds of coffee— far larger than any home user would ever need.
  • At 44 pounds this thing weighs more than most espresso machines!
  • At just over two feet tall it will make the standard-sized home espresso machine look like a two-slice toaster.

If you are still following along, consider yourself a coffee enthusiast.

Why Would You??
     Why would anyone want such a grinder for home use? That's a good question! This thing is a monster, will not fit under any kitchen overhead cabinet, and resists being moved like a stubborn mule. You wouldn't take it on vacation, and the hopper holds more coffee than most households use in two weeks... or more. And it's expensive. So why do I own one? It possesses some features that make it stand out in the sea of espresso grinders:
  • The 350 watt motor is connected to the burrs by a gearbox that spins the burrs at a relatively slow 500 RPM. A slower grinding speeds means less heat and gentler handling of the beans during the grinding process.
  • 63mm conical burrs offer a much larger total grinding area than most flat burr grinders. The conical advantage also gives a more gradual decrease in particle size as the beans migrate downward through the burrs so that, at least theoretically, there is a more consistent particle size with less dust. If you check the Titan Grinder Project you will find graphs of particle size from data gathered using a laser diffraction particle size analyzer. Really.

Did I Order A Condominium or a Coffee Grinder?
     When it arrives you know you just received something substantial. The 12" x 18" x 24" box (three cubic feet!) is a real handful to get into the house. It doesn't take long to see that this grinder was designed for serious, heavy-duty use. Once on the counter (Phewww!) install the hopper, place the hoper and doser covers on, attach the built-in tamper if you desire, and slide the catch tray under the front of the machine and it is ready to go.

The Burrs
     With any coffee grinder it's the burrs that do the work. To do that work the best way possible you need precision burrs held in precise alignment. This alignment means that lots of metal is needed. The shaft that spins the lower burr must sit in precision bearings and there must be a thrust bearing that does not allow any movement in the vertical plane. The upper burr must be help in a parallel plane to the lower burr and it must be as nearly perfectly concentric as possible which is particularly important with a conical burr grinder. The entire body of the Kony is die-cast metal, and the top, chrome area is massively heavy and solid feeling. With the exception of a few parts (the bean hopper, clear doser window, power switch, doser handle, doser and hopper lids, and the power cord grommet) there is virtually no plastic in this thing anywhere. Even the grounds catching tray is stamped metal.

     When speaking of serious espresso grinding, a weakness of the Rancilio Rocky is the amount of play that can develop in the threads of the upper burr carrier. All threads have some space between them, even if it is microscopic, or else they would be virtually impossible to turn. Rocky depends directly upon those threads for burr adjustment s well as alignment. Many folks have resorted to putting teflon tape on the carrier threads to steady the carrier. One of the reasons I narrowed down my choice of grinders to the Mazzer line was the way the upper burr is mounted. Let's take a close look:

     Unscrewing the retaining bolt at the rear of the bean hopper (made to be removed without tools) allows you to lift off the entire hopper assembly. The hopper is equipped with a sliding gate so that it can be removed while still full. The lid is also a tight fit so it won't be easily knocked off. Note the tab at the rear of the hopper. The tab fits into a slot which activates an internal safety switch so that the grinder cannot be run without the hopper in place. That's a good thing, because with the hopper removed the burrs are exposed and capable of mulching a desk chair! Beneath the hopper, still mounted to the grider in this picture, is the grind adjustment ring, stamped with the grind setting numerals 0 through 9, with each intermediate section divided into ten segments.

     Unscrewing the grind adjustment ring (reverse threads) allows it to be removed from the grinder without tools of any sort other than your hands.

     With the adjustment ring removed the upper burr carrier is revealed. This is now free to be removed by simply lifting it off the grinder. There are three "fingers" (two seen in the image above) that protrude from the outer edge of the upper burr carrier. These fit into the cutouts in the grinder's top. Lift off the upper burr carrier...

     ...and you see the springs that support the carrier and keep it in place. The springs are compressed as the adjustment ring is rotrated towards a finer grind. In this way, regardless of any play in the threads of the adjustment ring, the upper burr is held firmly in place by the strong springs' compression force. The upper burr cannot move during the grinding process. If the threads do suffer some wear, the necessary grind setting will change only slightly, but it does not affect the grind process itself, nor will the upper burr be thrown out of its accurate alignment.

     Beyond the infinite adjustability that such a mounting system offers, without using any tools you can access the grinding chamber and both burrs, and then reassemble the grinder, all in less than 90 seconds, without rushing. The repeatability of the grind setting even after disassembly is extremely accurate as well. While this is a time saver and thus a money saver in actual commercial use, it is a real joy in the home— no tools, no dropped screws, and no wasted coffee searching for the grind after reassembling.

     After unplugging the grinder, I removed the bottom to reveal a serious mass of electrical parts. Two large starting capacitors, a huge power switch, wire connectors, a relay, and up inside beyond all that is a massive motor designed for decades of heavy duty use. On top of the motor, unseen here, is the gearcase which steps down the motor's RPMs to be kind to the coffee. Expect this grinder to give a lifetime's use in the home environment. (NOTE: in the above photo I have temporarily removed the doser.)

MODS – Have tools, Will Modify
     Once I decided that the grinder was going to be a keeper (which didn't take long), I began the modification process. One of the first things I did was to remove the entire flapper switch assembly that regulated when the grinder turned off. Since I will never, ever grind until the doser is full there was no need to keep it. Removing it makes the doser easier to clean out and it also gives full access to the exit chute from the grinding chamber.

     I did not mount the built-in tamper to the front of the doser and I removed the stiff metal clip from the underside of the grinder that was meant keep the grinds tray in place. The clip was so stiff, and holding the tray in place with such authority that the tray was scratching my counter top when I slid the tray in and out of place.

     Finally, I removed the doser forks which makes it much easier to dose evenly into the portafilter. The bottom needs to be removed for this procedure since the screws holding the forks merely go into loose nuts inside and not into a threaded boss. If you do manage to get the screws out, the nuts drop hither and yon into the grinder where they could create an electrical short hazard.

     Not to worry. All the above modifications can be easily reversed, and the grinder will be reverted back to its stock configuration if I ever decide to sell you my Kony... and then you woke up.

Putting It To Work
     It didn't take me long to get it dialed in. I noticed right away that I no longer had to use the WDT to break up the clumps and evenly distribute the ground coffee in the basket. The Kony created a fluffier grind that distributed much better on its own. When a clump or two did appear, they seem to be less structurally sound, and they broke up upon tapping the portafilter downward on the counter top and if not, during the standard tamping process. I rarely see any sprites or channeling, and I never use the WDT any longer... and I don't miss it.

     One thing I did notice right off was that the espresso tasted different, at least to me. While it worked quite well in milk-based drinks, as straight shots, the grinder seemingly changed the taste profile. It became more intense, seemingly accenting the varietal notes, roast flavors, and other tastes while muting the smooth and mellow flavors I savor more. This mirrors the results that some of the testers experienced in the Titan Grinder Project at

     I have since begun changing my blend and roast to match this new setup. I am now roasting lighter for espresso than I have in the past. For quite some time (years?) I had been roasting about fifteen seconds into active second. To adjust the flavor profile, my last roast was taken about ten clicks into second, and I will continue to experiment to find a roast I like, but can definitely see where I might be roasting even lighter than that. I can only conclude that the grind produced by the conical burrs brings out flavors not previously revealed using Rocky.

     I have also begun modifying my blend. I was using a Brazil base of about 33%, added another South American (Peruvian, Costa Rican, Panamanian, etc.), and topped it off with about 20 to 25% Asian or African (often a Kenyan or Tanzanian peaberry). To try to mellow out the taste of my espresso with the Kony, for this last roast I used all South American beans and the straight espresso was much improved. Based on the lighter roast and the taste of this last batch of coffee, I can probably roast even a bit lighter (maybe the first click or two of second) and add about 10-15% African. If that doesn't work, I will post-roast the African a bit darker and try that, or maybe try something else.

     I can only comment on the two espresso grinders mentioned above as they are the only two I have used extensively. I have no idea whether other conical burr grinders have the same effect on the taste of espresso.

     I will say that I am quite glad that I home roast and can easily modify my blends to match my taste, and in this case, to match my equipment as well! This is part of the joy and one of the two greatest benefits of home blending and home roasting (the other, of course, is guaranteed freshness). What would I have done, as an "average" home-espresso enthusiast if I bought green espresso blends or if I bought nothing but pre-roasted coffee for espresso? I very well might have sent the Kony back or sold it. That might be even more true if I predominantly drank straight espresso.

     So, does the Mazzer actually reveal tastes that “lesser” grinders miss? Do other grinders leave tastes in the coffee which end up in the knock box? I can't really tell you what is actually going on other than what my taste buds have seemingly revealed.

     If you are looking for more, the Mazzer Robur may be what you want. At 62 pounds, massive 71mm conical burrs, and a 900 watt motor, that workhorse may well set you back about $2400. Looking for less? The Mazzer line has lots to choose from, including some flat burr offerings which are relatively affordable, and they share the same upper burr mount design which makes the Mazzers a top pick in my opinion.