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Grinding speed

edited January 1970 in Grinders
Hi everyone

I came across this interesting article the other day. Amongst other points, the author made some comment regarding commercial grinder speed (output) and how this affected the pour/taste; in his experience, a grinding rate exceeding 2 g/s resulted in a "thin"/weaker flavour in the cup.

I use a Robur at home, and although I haven't timed it, some net searching suggests 5 or 6 g/s. I enjoy the coffee I make at home, but it has me wondering ...

At work, I use a hand grinder (Portaspresso Rosco, 38 mm conical burrs vs 83 mm in Robur). Now, the grinding rate on the Rosco is far slower, but one thing has always struck me - the aroma while grinding is far stronger using the Rosco than what I experience from the Robur. Does this mean it tastes better? No idea, I have never properly trialled them side-by-side keeping other variables constant.

But I'd be interested to hear if anyone else has thoughts on this and whether our big grinders are spinning too fast? I see someone on the internet has tinkered to reduce the output speed of a Robur ....

Cheers, Dan


  • Hmm.. interesting. I reckon it’s a project however for a better palate than mine ;) My Robur is a joy and part of that joy is the grind speed and ease of sweeping the chute for single dose.
  • Not sure I completely agree with some of the comments, or observations expressed in the article. And who uses a 500w grinder in a busy bar......surely they would be using bigger boy's toys! In particular, the grind speed I've found no real differences across the entire spectrum from terribly slow to blindingly fast......and that's over 38 years of wrestling with grinders of all sorts. I can't honestly say that slower grinders taste better......all I can say is faster grinders tend to appeal to my preferences better and that's probably because they are conicals. Invariably, during the day I may revert back to a slower grinder as the other hoppers are occupied, besides the rolling of the eyes from waiting, waiting and waiting forever for the portafilter to fill with grounds, perhaps my impatience boils over and I cuss at that slow slug, it's never going to receive a fair opinion. Each model of grinder has it's own set of nuances - it's up to the operator to first understand and then exploit what works well and workaround what doesn't. Some grinders are more forgiving than others and yet I've even owned and used grinders from the same manufacturer that were utter dogs (or Lemons for want of a better term). 3x of them is a dog.....all built within a couple of months of each other. Some of the most amazing cups I've experienced have been off the Mazzer Kony E which is a smaller conical than it's big brothers the Kold and Robur. I've also enjoyed coffees from Compak E10 and F10's at work, along with a bank of EK43's, but give me the Kony any day as the preferred weapon of choice. The distinctions are clear between flat burr and conical across all the manufacturers. I've never managed to enjoy cups from Mythios (although not tried the version 2 yet) but I tend to put some of that down to the "memory effect" of what I like in a cup from conicals - it seems that every time I taste a cup from a flat burr, it's not quite hitting the spot for me. Psychosomatic ? who knows !.
  • That's great insight mycuppa ... thanks for sharing. You got me thinking about a Kony now  :P And Brett, I am always amazed at the effort some people put into testing things out, and I would very likely be in the same boat in actually being able to taste differences. Did you see that little chain mail mod the guy had on his chute exit - interesting.
  • Another fabulous post Jeff - thank you! Yep DrD, I sure did see the declumping device and it broke my brain. It flys in the face of everything I know about the less grinds held back, the better.
  • The post referenced is an advertisement for a Grinder specification that only their developed grinder meets. I would relax. Grinders, used in the home environment, especially big conicals like the Kony or Robur don't heat at all. It is true that if you run a busy café even these grinders can run hot and definitely the Robur has a fan in it. I have the Robur and it is nice having a conical that makes short work of any grind and can be adjusted from Turkish to filter with espresso as well. Conicals like this are also nice to use and easy to keep the setpoint for an espresso grind. Very few throwaways shots and low rpm of 420 for the Robur. Overkill maybe for home use but lovely...:)
  • Just KIS people - kiss it simple :) I really think some people take things too far sometimes. I would really love to run a blind test on that “burr speed detecting” guy ;) Just KIS and enjoy great coffee. That’s my 2c ! Paul
  • on 1570709695:
    Just KIS people - kiss it simple :) I really think some people take things too far sometimes. I would really love to run a blind test on that “burr speed detecting” guy ;) Just KIS and enjoy great coffee. That’s my 2c ! Paul
    Mind you Paul you don't like big commercial grinders (for home use). I forgive you...:) I will come to you for a new grinder when the 28kg Robur gets too heavy to lift. You could argue too that the Mazzer line of grinders until the recent S models were the most simple on the market, no circuit boards and software. Look at some of the espresso machines coming out too that must have half a mile of wiring inside and a number of different sensors and a chipset that is all throwaway once cooked. All in the name of chasing the perfect shot but at great expense sometimes. Cheers, Grant
  • I would say that whether your blades are sharp or not is going to have more of an impact on taste as will dose and grind settings. I don't mind flat burrs either in my experience they produce a more well rounded coffee with greater depth of flavour on the mid palate, but perhaps without the brightness and vibrancy of conical burrs. But again that might just be me - besides if it ain't broke don't fix it!
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