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Thread: Grind speed ?

  1. #1
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    Grind speed ?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Just a quick question. For those with grinder expertise....
    With the "common" 64mm dia flat burr grinders ,...Mazzer Mini E!, SJ, Macap M4, Compak K6, Quamar M80, etc etc,
    there have been several comments regarding the difference in time taken to grinde a typical 20gm dose.
    everything from ~~5 secs way up to 20+ secs.
    given that most of these grinders run at similar burr speeds ,..1400-1500 rpm, what is it that results in such big differences in grind time ?
    i suspect it is something in the burr tooth design/configuration, but cannot say for sure.
    Further, I don't see any obvious relationship between grind speed (time) and grind quality.... Has any been noticed ?

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    Senior Member Yelta's Avatar
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    Cant comment on the various grinders, however, regarding speed of grind, the faster the grind speed the more heat will be generated, not a desirable thing to do to fresh beans.

    I have a Mazzer Mini, takes approx 40 seconds to grind 18 grams for espresso (perhaps the burrs are a little worn) it generates very little heat, certainly not a speedster, never has been, from recollection even new it took approx 30 seconds to grind 30 grams.

    One of the reason high end hand grinders are revered is because they are low speed, they generate virtually no heat.

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    ..? 40 secs for 18 gms !!.... I don't want this to become some form of weird competition, but that is impressive !
    Just to be clear , is that a Mini (58 mm burr), or Mini E with 64 mm burrs ?
    Do you think the beans are actually spending any more time "in the burrs" than in a faster grinder, ..or just more time "waiting" to be ground ?

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    SJ is about 13 seconds for 18g

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    Senior Member Yelta's Avatar
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    Quote Originally Posted by blend52 View Post
    ..? 40 secs for 18 gms !!.... I don't want this to become some form of weird competition, but that is impressive !
    Just to be clear , is that a Mini (58 mm burr), or Mini E with 64 mm burrs ?
    Do you think the beans are actually spending any more time "in the burrs" than in a faster grinder, ..or just more time "waiting" to be ground ?
    Its a Mazzer Mini 58mm.

    Re question two, I suspect a little of both.

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    Quote Originally Posted by blend52 View Post
    Further, I don't see any obvious relationship between grind speed (time) and grind quality.... Has any been noticed ?
    Can't comment on the 64mm flat burr but I have a hand grinder and an electric grinder with near identical conical burr sets (I think only the keyway on the inner burr is different). Grind time for a double is 15-20s from the hand grinder vs ~4s from the electric so quite a big difference. If I single-dose both grinders then the shots from the hand grinder are noticeably better. But with a partially filled hopper the electric grinder may have a slight edge. Just because it doesn't require any re-distribution. But it'd be really really close... Too close to call.

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    The finer you grind the slower the grinder will do its job.
    The Mazzer SJ at work is in the low teens for a 19 gr dose. Which I have trouble with, feels like forever when there is a line. I think it runs at 1200 rpm from memory
    The Major E is set at about 7.5sec
    The Kony E I have is set at 5.5 sec for 20gr (at home)
    The Robur E is about 4 sec for 20 gr

  8. #8
    TC
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    It comes down to brand and how aggressive the (planar) burr cut is:

    • Mazzer mini 58mm- not aggressive slooooow
    • Mazzer mini-e 64mm- does it have teeth? See above
    • Macap M4 58mm- as per Mazzer mini
    • Macap M4D 58mm with teeth. Circa 10.5 sec double
    • Mazzer SJ-E 64mm with some teeth. Circa 13 sec double
    • ​Grinders with 83mm burrs- circa 4 sec double

  9. #9
    Sleep is overrated Thundergod's Avatar
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    I thought I'd wade in.

    My Macap M5 grinds 18g in about 30 seconds.

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    Coffee+carbon=heaven Mono's Avatar
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    Geez, could cook my toast & go to the drive way and collect the paper with some of those grind times and still get back with time to spare. Kack :-) :-)

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    Yes, some of those times are crazy, !.. Even my old Rocky managed less than 20 secs for 20gms.
    T'god,.. 30 secs for your M 5 ....There has to be a problem ?? Has it always been like that ?

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    I know this could well open up people talking bout crazy factory grinders with 200mm burrs or whatever, but an EK43 will eat through 250g in about 15 seconds - the same time as the SJ will grind a double. Yikes.

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    Quote Originally Posted by Bames View Post
    I know this could well open up people talking bout crazy factory grinders with 200mm burrs or whatever, but an EK43 will eat through 250g in about 15 seconds - the same time as the SJ will grind a double. Yikes.
    yes , I was hoping to keep it focused on the mid range 58-64mm flat burr size grinders, so as not to over complicate things, and identify the reasons why some are so much faster than others and, most importantly, if there is any relationship between grind speed and quality of the grind ( fines, clumping, static, etc)
    Also, it may be useful to know what is "normal" grind time for a good condition burr set in a specific m/ c , such that owners may be able to recognise worn burrs....if they do indeed cause longer grind times.
    Talk Coffee,s post has set some good base times for a few machines I believe.
    i raised the issue after a change up to a 64mm Fiorenzato which will serve up a fluffy, clump free 20 GM dose in 6-7 sec,s (single dosing beans), which was a huge change compared to the Mazzer and K3 I had used previously.

    As an example, I can now understand why I occasionally see comments from users who change their Mazzer Mini E burrs for the SJ set .

  14. #14
    TOK
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    Interesting thoughts, however...

    Grinding times are what they are, for different grinders, and for home use may I surmise speed is pretty much irrelevant. On the other hand it may be extremely important in a cafe situation. Remember, speed and a lot of grinding = deteriorated grinds from the production of heat by friction. Not that grinding for a few seconds in a single sitting in a home situation is going to be an issue....except if you think it is.... And therefore I cant really understand why people go looking to fit plates from other models to their grinders, on the basis they will grind more quickly. So what?

    I don't really think that having a "timing chart" is going to solve any issues in terms of whether plates are worn or not. I don't necessarily believe worn plates will grind at a significantly different speed to plates in good condition, such that you could point the finger straight at plate condition if grinding speed of any particular machine differed from whatever it *theoretically* was when an arbitrary set of plates were new. And what about differences between plates from different manufacturers or made form different compounds, that are said to be "equivalent" or able to be fitted.

    As plates wear, it becomes rather, a factor of the extreme non uniformity of the grinds, and the resulting heating/deterioration of the grinds due to both factors working together against quality... In badly worn plates this is significant, but at that stage the plates should have been changed out some time before and should never have been allowed to go there....

    If the coffee tastes good. Whats the problem. If it doesn't, plate condition is just one aspect of quite a few variables to think on.

    Anyway that's my take.
    Dimal likes this.

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    for home use may I surmise speed is pretty much irrelevant.
    Certainly not for me. !
    If there is one thing i dont want in my morning rituals its unnecessary noise. I realized early on that all grinders ( actually the beans) make a certain level of intrusive noise as they grind, and reducing the noise was much more tricky than simply reducing its duration.
    I am sure i would not be able to tolerate a 30+ second dose. I suspect others may of the same opinion.
    My dream would be a "instant " grind dose.
    So, why do Mazzer fit "Slow" burrs in the MiniE,.. if they have interchangeable "Fast" burrs available as fitted to the SJ ??
    It cannot be grind quality, as the SJ is generally considered a step up from the Mini, and reports from people who have swapped in the SJ burrs also suggest its a definite quality improvement as well as grind time reduction. ( I can see there may be a motor power question, but it doesnt seem to be a problem in practice)
    And why, apparently do Macap fit different geometry burrs ( faster) in the M4D as compared to the M4M ??
    There must be a good reason, but i struggle to understand.

    Remember, speed and a lot of grinding = deteriorated grinds from the production of heat by friction.
    So what are you implying here ?.. fast grinding generated more heat in the grinds ? ( even though the actual rpm of the burrs is the same)
    I would have thought that slow grind times allows the grinds more time being "worked" and hence gain heat..?
    ..but i have seen no data tho verify that either way.
    It is obvious that Grinder/Burr manufacturers have the ability to chose a burr design that can give a "fast" grind time...apparently without direct impact on grind quality,.... so why do they chose often to go with "slow" burr designs for some models ??
    I can see the advantage of a fast grind time , but fail to see any reason to deliberately extend the grind period ? ( other than possibly motor power, and that is trivial at these levels )



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