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When is a Grinder not a Grinder but a Mill

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  • When is a Grinder not a Grinder but a Mill

    Jim Schulman does a good analysis of grinder mechanics.
    More than you ever wanted to know about burrs

    http://www.home-barista.com/espresso-grinders/grinder-burr-types-explained-flat-conical-drm-t1672.html

    Grinder mechanics as a design specification is actually a mill
    In the coffee industry grinders are called mills.

    The technical term term is called particle reduction
    This quote says it quite well

    Quote from homeroasters member Dan.
    But why the complex shapes and angles on the burrs? Thats easy too, once you know the physics. In particle reduction, the most you can reduce a particle size at any given step is about 1/5th the original size. The answer to getting something finer than 1/5th is to use a series of progressively finer burrs. Each step "cracks" the particle into smaller pieces. Jim shows this clearly in the photo he marks up showing three steps on the burrs. He gets the first step right: bean breaking, but the next two wrong: coarse grind, fine grind. Actually, they are: particle reduction step one, two, and three. Three steps seem to do the trick for coffee. Some materials only need one or two steps, some need five.

    So, to wrap this up. the first step takes a coffee bean, lets say it is 0.5" long, and reduces it about 1/5th to 0.1", step two reduces it again by 1/5th to 0.02", and the final step reduces it by 1/5th again to about 0.004". Opening the burr set then allows larger particle sizes to pass through.
    So should we start changing the names from Grinders to Mills

    :-?

    KK

  • #2
    Re: When is a Grinder not a Grinder but a Mill

    Originally posted by 4C6861616262584C68746A68070 link=1234666330/0#0 date=1234666330
    The technical term term is called particle reduction  
    The other day I was reading in "Espresso Coffee - the science of quality" (Illy, Viani), chapter 5, refers to it as "Communition" (in engineering language).
    Besides being the best book ever, its got a great chapter on communition of coffee beans, or grinding. I reckon its a good read for ya KK.

    Talks about grinding in terms of crushing and cutting, and what goes on with grinders for coffee. Hmm, without typing out the whole chapter, Id still call it a grinder. A mill still grinds - its a grinder haha.

    In short, read the book haha. (sorry mate, I found myself going from one point to the next, with the following point alluding to the last)

    Comment


    • #3
      Re: When is a Grinder not a Grinder but a Mill



      Originally posted by 6E72726D76170 link=1234666330/1#1 date=1234667848
      The other day I was reading in "Espresso Coffee - the science of quality" (Illy, Viani), chapter 5, refers to it as "Communition" (in engineering language).
      Besides being the best book ever, its got a great chapter on communition of coffee beans, or grinding. I reckon its a good read for ya KK.
      I will have to read this book Yeeza
      This is a definition of Mill from a dictionary

      1. A machine for grinding or comminuting any substance, as grain, by rubbing and crushing it between two hard, rough, or intented surfaces; as, a gristmill, a coffee mill; a bone mill.
      This a definition of Grinder

      1. One that grinds, especially:
      a. One who sharpens cutting edges.
      b. A mechanical device that grinds: a meat grinder.
      2. A molar.
      3. grinders Informal The teeth.
      KK

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      • #4
        Re: When is a Grinder not a Grinder but a Mill

        LOL...

        I spose when you get right down to it, a high quality coffee grinder(mill) is more simply described as a precision cutting tool as it neither grinds nor mills the bean, in the strictest sense of the etymology of the words used.

        Coffee grinder seems to roll off the tongue a bit easier though.... :P

        Mal.

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        • #5
          Re: When is a Grinder not a Grinder but a Mill

          Originally posted by 6944404C412D0 link=1234666330/3#3 date=1234777214
          LOL...

          I spose when you get right down to it, a high quality coffee grinder(mill) is more simply described as a precision cutting tool as it neither grinds nor mills the bean, in the strictest sense of the etymology of the words used.

          Coffee grinder seems to roll off the tongue a bit easier though.... :P

          Mal.
          Words, one can never find one the right one!

          A mill in my mind is like a flour mill. Grains crushed on a flat stone via the force of large rolling stones. Yet when I think about it so does a mortar and pestle. Should we call them a mill?

          A grinder to me is like a fast moving stone abrasing a surface. Like an angle grinder. But really it just doing the same as a manual file. But then a file is a metal cutting device that reduces the particle size depending on the teeth size, bit like a coffee grinder.

          A coffee grinder/mill seems to do both/neither? Grinder is just the venacular.

          Sounds like the vibrating pump = solenoid pump = reciprocating pump arguement.
          The pump vibrates! Ah but it uses an electronic solenoid to do it. Yes but it goes back and forth so it is a reciprocating pump. Well a car engine is also a reciprocating pump so it doesnt really describe it properly............

          As long as every one knows what is being described I guess it really doesnt matter, thats the point of language - to communicate.

          Then again this debate has made me look at the links/grinders (sorry.... mills.... errrr.. precision cutting devices) and have better understanding of how they work.
          Thanks.

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          • #6
            Re: When is a Grinder not a Grinder but a Mill

            I would think the term mill goes back to old flour and grain mills using stones to break the grain down. Some of the early Turkish and Greek coffee grinders actually have stones in them so to my way of thinking they are mills. Garanti still makes comercial ones today with electric motors. http://www.garantiroaster.com/3ing.html

            Grinders are a modern invention as far as I know involving hardened steel cutting faces when it comes to grains or coffee but there has been hand grinders for grinding metal using stone wheels for a few hundred years so go figure.

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            • #7
              Re: When is a Grinder not a Grinder but a Mill

              Ive seen one of those stone Turkish coffee grinders in the back room of a little cafe in Newtown.
              So old and so cool. 8-)

              Back to the words.

              Theres been some discussion above about the "action" of the device justifying the name.

              It doesnt have to be the case.

              A rose by any other name would smell as sweet.

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              • #8
                Re: When is a Grinder not a Grinder but a Mill

                Hi TG,

                most of the new turkish/greek ones actually use burrs like electric grinders you would need to get early 20th century or before to get stone in most cases. My Zass for example is referred to as a kneemuhl (bad spelling I think) or knee mill with toughened conical burrs.

                Whats in a name I guess

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                • #9
                  Re: When is a Grinder not a Grinder but a Mill

                  And then there is the Turning Mill used in metal/materials machining that sometimes uses cutting tools that are very similar in appearance to that of a decent coffee grinder.... :-?

                  Mal.

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                  • #10
                    Re: When is a Grinder not a Grinder but a Mill

                    Originally posted by 4641454A42485D4D4A43240 link=1234666330/5#5 date=1234930666
                    but there has been hand grinders for grinding metal using stone wheels for a few hundred years so go figure
                    I have one of these geared/stone, hand crank grinders that you mentioned
                    I use it regularly for delicate work
                    It has a hand clamp that attaches it to a workbench

                    I will take a photo and post it when I get a chance

                    KK

                    Comment


                    • #11
                      Re: When is a Grinder not a Grinder but a Mill

                      Originally posted by 6F686C636B617464636A0D0 link=1234666330/7#7 date=1234937748
                      Hi TG,

                      most of the new turkish/greek ones actually use burrs like electric grinders you would need to get early 20th century or before to get stone in most cases.  My Zass for example is referred to as a kneemuhl (bad spelling I think) or knee mill with toughened conical burrs.

                      Whats in a name I guess
                      My Macap grinds fine enough for Turkish.

                      Comment

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