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Thread: electric grinder with speed control

  1. #1
    Senior Member summercrema's Avatar
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    electric grinder with speed control

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Can anyone recommend few electric grinders with speed control function? Thanks

  2. #2
    Senior Member Yelta's Avatar
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    Have never seen one, doesn't mean they don't exist.

    Varying the speed of an electric motor under load doesn't seem like a good idea to me, Dimal is the electronics guru, perhaps he would care to comment.

  3. #3
    Senior Member level3ninja's Avatar
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    It can be done with a Variable Speed Drive (VSD). Whether a grinder motor will be agreeable to that I don't know. Also you would have hook up just the motor to it, couldn't just plug the whole thing into a VSD if there were electronics controlling it etc. If it was just an on/off switch it should be ok too plug the whole thing in. I have a strong suspicion that the whole bean path including the burrs may have thresholds of speed they work within, and that they will be quite close to the full speed rpm. Especially flat burrs. I am inclined to think that each grinder will operate best how it is designed and if you want a slower grind, get a slower grinder.
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  4. #4
    Senior Member magnafunk's Avatar
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    I believe the kafatek monolith flat has variable speed control

  5. #5
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    Lyn Weber EG-1 also has speed control
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  6. #6
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    It unfortunately fails the electricity requirement but the HG-1 also has speed control....
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  7. #7
    Senior Member Barry O'Speedwagon's Avatar
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    Black & Decker Power Drill + Porlex Mini combo.

    I'm not sure that there too many 'off the shelf' variable speed electric grinders.
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  8. #8
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    Quote Originally Posted by Melbroaster View Post
    It unfortunately fails the electricity requirement but the HG-1 also has speed control....
    Range of speed control is also somewhat limited!

  9. #9
    Mal Dimal's Avatar
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    Quote Originally Posted by summercrema View Post
    Can anyone recommend few electric grinders with speed control function? Thanks
    G'day mate...

    Why do you want speed control in the first place?

    Mal.
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  10. #10
    Mal Dimal's Avatar
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    A.C. VFD's are normally most effective with motors that are designed to be operated with them.
    Using an "off the shelf" VFD to drive a typical split-phase motor as used in most commercial type grinders, will have a very limited speed range and duty cycle. Motor overheating will be a genuine concern...

    Purpose built V/S grinders, as per the units referred to above, won't suffer these sorts of limitations...

    Mal.
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  11. #11
    Senior Member LeroyC's Avatar
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    Quote Originally Posted by K_Bean_Coffee View Post
    OP - it's about slower grind to reduce heat build up.
    Latest research indicates that's not actually true.

  12. #12
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    I'm led to believe that speed differences change grind particle frequency distribution and therefore extraction characteristics. It's arcane though. I haven't personally felt the need to alter grind speed on my grinder.

  13. #13
    Senior Member summercrema's Avatar
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    Quote Originally Posted by Dimal View Post
    G'day mate...

    Why do you want speed control in the first place?

    Mal.
    I got both Mini mazzer and a Manual ROK grinder, during week days I use the Mini, it is only weekend I use the ROK I must say both are doing a good job and really the ROK can bring out a deeper aroma from the beans I think the slow rotating speed might have something to do with it.

  14. #14
    Senior Member LeroyC's Avatar
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    Quote Originally Posted by summercrema View Post
    I got both Mini mazzer and a Manual ROK grinder, during week days I use the Mini, it is only weekend I use the ROK I must say both are doing a good job and really the ROK can bring out a deeper aroma from the beans I think the slow rotating speed might have something to do with it.
    No I'd say it's probably more to do with the burr shape as you've got planar versus conical there. Both are good in their own way, but my experience is that they affect flavour differently.
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  15. #15
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    Quote Originally Posted by summercrema View Post
    I got both Mini mazzer and a Manual ROK grinder, during week days I use the Mini, it is only weekend I use the ROK I must say both are doing a good job and really the ROK can bring out a deeper aroma from the beans I think the slow rotating speed might have something to do with it.
    The deeper aroma from Rok is 99.9% because the Mazzer Mini is contaminated with older stale ground coffee, not due to the rpm. When was the last time the Mazzer Mini stripped off for cleaning? Mazzer Mini will also happily contain up to 10g or more ground coffee in the burr housing if you use the grinder as intended without any modification. That's another reason why the coffee can be inferior compared to the Rok.
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  16. #16
    Senior Member LeroyC's Avatar
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    Good point. The virtually zero retention of the ROK could be making a difference for sure.

  17. #17
    Senior Member summercrema's Avatar
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    it is true I hardly clean the grinder, a cleanup is long overdue I better do that first.



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