Remember kids….

Keep an eye on your burrs. There is a great deal of chatter on the net about grinder maintenance but 95% of it is focused on espresso grinders. Granted – the effects of not looking after your espresso grinder are more obvious but I think people kind of forget their other coffee grinder and it needs a little love too.

Recently I picked up a Bunn G3A and it needed a little love. Bean hopper was pretty nasty, ground coffee exit and burr area all a bit nasty with old built up coffee. Stripped it down and put new burrs into it. Its interesting to see where the wear and tear had happened on the burrs – mostly on the large breaking teeth:

Old:

New:

So – what condition are your filter grinder’s burrs in? When did you last open the grinder up to have a look? I strongly suspect it is an area we all too easily overlook in our weird obsession with espresso. I thought a quick poll might be interesting:

{democracy:1}

Having changed them I am enjoying, and am about to enjoy again, a Chemex of El Bosque’s Bourbon from Guatemala. Lovely stuff – really pleasing body, but a very clean cup (though this may also be the brewing method – still getting to grips with it!) and maybe a little spice. I might have to have another!

[tags]grinders, bunn, burrs, burr, grinder burrs, espresso grinders, espresso, cleaning, guatemala, chemex[/tags]

8 Comments

  1. Call me a philistine, but I didn’t even know there were specific grinder types, but I suppose it makes sense.
    Are they just differently designed burrs or are they an entirely different beast?

  2. Most people use bag/bulk grinders for their filter coffee/clover/french press/anything but espresso.

    They usually have vertical burrsets (unlike the horizontal ones in espresso machines) and the burrs are often cut a little differently – and are a bit bigger allowing a high volume of coffee to be ground per minute. Mahlkohnig, Bunn and others do good grinders for this purpose.

  3. so what does the difference in burr design achieve then? is it just an increase in grams per second throughput or is it more subtle? something like producing uniformly sized grounds or making the grounds a different shape?
    I’ve been wondering about grinders for a couple of days actually and i was trying to work out if burr speed increases grind temperature then why don’t espresso grinders have larger and slower burrs, is it down to the torque on the motor or financial reasons or what?
    i tend to do this sort of thinking when i really ought to be thinking about more useful stuff

  4. There are different burr designs and speeds on the market. Conical burr grinders turn slower but are able to grind more coffee per minute due to the larger contact space. Motor torque does affect things and this is one of the reasons burr grinders are more expensive.

  5. Forgot to mention burr design in general – this is an area where there really isn’t enough information in the public domain. Most grinder manufacturers make their own custom spec burrs – certainly people like Mahlkonig. How the coffee is broken down into different sized pieces has an effect on the final grinds as well as heat generated.

  6. I suppose that’s what I was trying to get at, it seems that because coffee machines are so glamorous, and grinders are, at least to most people, just something that the supermarket has, or are a fancy electric drill attachment in essence, people don’t seem to pay much attention to them.
    I wonder if anyone has done any research into how the crack mechanics of the bean work in breaking it up (ie, when you compress it, as the first stage of the burr would) rather than just thinking of it as a mushy thing that needs to be chopped up. I know they do lots of research in the crisp world to achieve maximum crack propagation speed to give a really crunchy crisp, so maybe someone has done so on a bean.
    Also… (I really must learn to think in my head and not through my fingers) I wonder whether different grinders give different shape grounds (i.e. not different sizes, but actual different shapes, like flat ones and little cubes, or spheres). Would they sit differently and give different percolation rates? Hmm, another PhD thesis coming along…

  7. dang, james. you are doing a remakable job of finding ways to flaunt your new camera and its capabilities.

    how about a post on shower screen patterns?

    ;)

  8. Ha! I’ll have you know this was a legitimate post about how we clean our espresso grinders properly and obsessively and then forget our bag grinders and in no way a smug way to show the macro lens that I spend far too much time pressing up to things whilst chuckling to myself….. Honest.

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