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Thread: How to know when to replace burrs ?

  1. #1
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    How to know when to replace burrs ?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Ive had my rocky for a few years now, and I bought it second hand from someone else who probably had it for a couple of years before that. Problem is that I seem to be getting quite a bit of clumping when grinding at the level I need for a reasonable ristretto style pour... which leads to channelling and mouse tailing with many shots. I can take some photos of the resulting grinds to show the extent of the clumping, but just wondering if anyone has any tricks for getting rids of clumps without replacing burrs, or knows roughly when they should need to be replaced ?

    Cheers,
    Matt

  2. #2
    Mal Dimal's Avatar
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    Re: How to know when to replace burrs ?

    Gday AG,

    Dont know that "clumping" on its own is the progenitor for assuming that burrs may be excessively worn. I think its more to do with the proportion of "dust" to "cuttings" that is a better indicator. Ideally your grinder should produce no (or very tiny amounts of) dust. If you grind a small amount of fresh coffee onto a white paper towel and then spread it out over the surface of the towel, you should be able to see that the vast majority of the ground coffee is made up of small cuttings, rather than ground-up dusty fines. If the opposite is true, then maybe the burrs are on the wrong side of worn and need replacing.

    You can also tell by rubbing the freshly ground coffee between thumb and forefingers, it should have a sharp, edgy and gritty feel to it and when you brush it off your hands, there shouldnt be any fine dust remaining in the valleys of your fingerprints. All that being said though, you can buy a set of new burrs from CoffeeParts, one of our esteemed site sponsors for quite an innocuous amount of money and it may be worth doing. All the best,

    Mal.

  3. #3
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    Re: How to know when to replace burrs ?

    At my work we have a Mazzer Mini E and we recently got a Rocky (new) for decaf beans. The Rocky shows a lot more clumping than the Mazzer... I dont think its the beans but I havent done a comparison with the same beans from both grinders (might try it though now that I think about it).

    I read on-line somewhere that some people use a thin wire to mix and de-clump the coffee in the PF. You might try this to reduce channeling, etc.?

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    Re: How to know when to replace burrs ?

    Hi Matt,

    Ive heard various kilogram ranges, from 50 to 250. Jim Schulman is an advocate of replacing burrs as often as possible. Whatever the case, youll have to replace the burrs sooner or later, so you might as well pick up a spare set, put them in and if you feel there is no noticeable difference, you can switch back to the old ones. I think that the Rocky burrs are identical to the MD40 burrs if you want to buy from coffeeparts. Of course, a quick email to Pedro to confirm that might avoid some embarassment!

    Im actually currently debating whether to replace mine or sit out my burrs for a little bit longer and upgrade to something stepless like an iberital, compak or a mazzer.

    As for clumping, I dont really think that its that huge a problem. Frankly, on our Silvias the OPV is likely to be the biggest cause of clumping. I think that what dishchucker was referring to is the WDT, which always seemed a bit time consuming to me, but its worth trying at least once. Not that Ive bothered. Hmm ... mise well do it now, eh?

    If all else fails, remember that looking for the clumping point can always help you to dial in a new blend ;P

    Cheers,

    Luca

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    Re: How to know when to replace burrs ?

    thanks for the replies guys...

    I guess I should have been a bit more specific. I run a whole bunch of different beans through my grinder based on what Ive been roasting that week, or who has been kind enough to drop some beans my way... So i often find it difficult to get the grind just right for a particular blend for the shots Im after... Lately especially Ive found a lot of clumping with a few different beans, and Im not sure what to put it down to... and if its symptomatic of problems with the grinder which are in turn affecting my shots.

    It could also be the fact that Ive been watching far too many shots being pulled on Synessos recently...which is tainting my judgement of what constitutes a good shot.

    I may just pick up a spare set of burrs (and a naked pf while Im at it) and see if it helps.

    Cheers guys,
    Matt

    ps. yeh Luca Ive heard of the WDT method, and agree that Im not even half as obsessive compulsive as Id need to be to bother :)


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    Re: How to know when to replace burrs ?

    Sounds like youve been warming the lounge at Epic, A.G.!

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    Re: How to know when to replace burrs ?

    Quote Originally Posted by abstractgourmet link=1160979128/0#0 date=1160979128
    Problem is that I seem to be getting quite a bit of clumping when grinding at the level I need for a reasonable ristretto style pour... which leads to channelling and mouse tailing with many shots. I can take some photos of the resulting grinds to show the extent of the clumping, but just wondering if anyone has any tricks for getting rids of clumps without replacing burrs, or knows roughly when they should need to be replaced ?

    Cheers,
    Matt
    Hi Matt,

    In my experience, at this time of the year, clumping from the Rocky is a function of the increased relative humidity...a bit more moisture in the air will cause the ground coffee to bind.

    Are you working in an air conditioned environment?

    Cheers,

    Chris

  8. #8
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    Re: How to know when to replace burrs ?

    How old is the grinder, and on average, how much coffee do you grind per week.

    EG, average domestic use at say, 250 grams per week, for 4 years use, is roughly only 50 kilos use. In this scenario, the grinding plates are good for many years to come....

    It is rare for people in domestic use to need to change the grinding plates in their grinder except after many years use and in many cases the grinder by then has been relegated to other duties, given away, sold off, replaced etc etc etc.

    Balling up or clumping is a normal part of coffee grinding and is affected by many variables / or is indicative of certain conditions, including the fineness of the grind, the type of coffee, the style of roast, the type of grinder & as someone mentioned above the relative humidity of the season. *You dont see it with "doser" grinders because the action of the doser mechanism breaks of the balls or clumps, but it is easy to see in all manner of "doserless" or deli style grinders that just grind out through a tube at the front.

    As plates wear you find that you have to keep grinding on a finer setting which in itself is not a concern...realistically, it happens slowly over quite a long period. It becomes a concern when the amount of "fines" in the gind increases to a point that is not acceptable and with this increased amount of fines there is a lot of friction & heating generated during the grinding process....and ultimately this leads to poor extractions with very dark crema etc

    Again realistically, the situation is not helped by the inordinate amount of misinformation or scare mongering that finds its way cyclically regurgitated around the net about how often one SHOULD (in someones opinion) change the grinding plates, instead of simply advising that you change them when they tell you they are ready to be changed in the individual situation.

    Unfortunately without seeing what the grinder in question is actually doing with the coffee at hand, I (anyone) would have to be merlin the magician to advise any further but there should be enough information contained in this reply, for you to take an educated guess for your own situation.

    Oh one last thing. There are an awful lot of spare parts sold that never get used. Thats great for the supplier, but not so good for the consumer who doesnt get the benefit from hanging on to something "for a rainy day". *In addition, by the time the rainy day actually comes, you cant find that pesky spare part you were saving all this time! ;) and have to buy another.

    So if you are going to buy some grinding plates to see if there is any difference, just fit them and throw the others out... dont go putting the old ones back in if you cant see any difference.....otherwise you have wasted your money!

    Hope this helps.

    Regardz,
    FC.

  9. #9
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    Re: How to know when to replace burrs ?

    Thanks again guys for a wealth of information that has pretty much answered all my questions.

    I have the doser version of rocky... but I always take the top off so I can see the grind coming out of the shoot, which is where the clumping happens. I then have a little brush that I break up the bigger clumps with before dosing it into the portafilter. I think my main worry was that clumping in itself was a bad thing... which Im realising it isnt necessarily, or at least not a fault of the grinder specifically. I dont work in an air conditioned room, so humidity could well be a factor. Beans are always fresh though.

    Like most home users I dont go through a great deal of beans... a kilo or 2 max per week... so putting it in context, there is no way it should be a problem with the burrs wearing out yet... but I think like FC said, its hard not to get caught up in the upgradathon hype that is the world of online coffee.

    Testament to that is the fact that this morning I pulled a glorious double ristretto with no blonding or mouse tailing at all, just a slight change in dosing and a firmer tamp... So I guess we can consider this myth busted.

    Thanks to all for the informative replies though... and Grendel... Epic is rapidly killing all the fun of making coffee at home :|

    Cheers,
    Matt

  10. #10
    Sleep is overrated Thundergod's Avatar
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    Re: How to know when to replace burrs ?

    Epic is not having much affect on my having fun at home as Im on the other side of the continent.

    However, I am wondering how soon I can get to Perth. *:-/

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    Re: How to know when to replace burrs ?

    Quote Originally Posted by abstractgourmet link=1160979128/0#8 date=1161049743
    and Grendel... Epic is rapidly killing all the fun of making coffee at home :|

    Cheers,
    Matt

    Naaa - getting a taste of the target is what Epic is for. Plus I get to play with my own blends and roasts - variety!

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    Re: How to know when to replace burrs ?

    True... variety is great... but until I can afford a Robur and a Synesso, the quality and consistency of the pours Im getting at home is not going to come close to what those guys are pulling. Flavour profile just seems remarkably different to what I can get at home with the same beans...

    I guess it gives me an excuse to leave the house though :)

  13. #13
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    Re: How to know when to replace burrs ?

    Quote Originally Posted by grendel link=1160979128/0#10 date=1161055850

    Naaa - getting a taste of the target is what Epic is for.
    And an ideal location for a Perth chapter CoffeeSnobs meeting ;)

    Just got to convince Corey to allow us all through the doors (at the same time) ;D

    Does he do "Guests of the Landlord"? - An English pub used to lock us in after hours (the pain we had to suffer)!

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    Re: How to know when to replace burrs ?

    Quote Originally Posted by Thundergod link=1160979128/0#9 date=1161053612
    Epic is not having much affect on my having fun at home as Im on the other side of the continent.

    However, I am wondering how soon I can get to Perth. :-/
    Actually, I find Perth alot better than Sydney in many ways... slower pace, nicer weather. Perth is a beautiful place!!

    Yes, I live in Sydney... The City of Road Tolls and heavy taxes.....

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    Re: How to know when to replace burrs ?

    I keep having to go back up there just to make sure they are maintaining their standards - or at least that is my excuse.

  16. #16
    Sleep is overrated Thundergod's Avatar
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    Re: How to know when to replace burrs ?

    Quote Originally Posted by Thundergod link=1160979128/0#9 date=1161053612
    Epic is not having much affect on my having fun at home as Im on the other side of the continent.

    However, I am wondering how soon I can get to Perth. *:-/
    Good news!
    My ISP is running a competition and the prize is a trip to Perth. :)



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