# Lighter roast beans won't grind fine?



## phollingswo (Nov 29, 2013)

Hey guys. I just finished a batch of CH8 from Crankhouse and loved it. Got in touch with Dave there for a recommendation for something new to try. He recommended the Kilimbi Natural beans so I got a bag of those.

When I first tried to grind without changing the settings the grinder wouldn't budge at all. (Iberital MC2). I gave the wheel about 5 full turns coarser but still the same issue. I kept turning a lot and got it to grind a bit before it just gets stuck. After backing off the grind A LOT, I can get it to grind, but the flow is way to quick and the shot is sour (of course).

Really struggling to get the grind fine enough without the grinder really struggling.

Is this an issue with the grinder not being powerful enough? Or is it a sign that the burrs need replacing? Or is this just a common issue with lightly roasted beans? Is the answer to get it as fine as I can without the grinder struggling and then just tamp hard?


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## MediumRoastSteam (Jul 7, 2015)

As far as I know, the MC2 is capable to choke your machine easily, so grind finer should not be s problem.

My advice to you would be to always keep the burrs spinning when you adjust to grind finer.

And that's its downfall: because of the screw worm type of adjustment, it will take some time to get it right. So, if you have a feeling for how much to adjust, I'd suggest you do so with the hoper empty, and always make sure you purge enough grinds before you pull a shot so all the grinds in the basket are of the latest adjustment.

Hope that helps.


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## Mrboots2u (May 10, 2013)

Keep adjustong finer


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## phollingswo (Nov 29, 2013)

Mrboots2u said:


> Keep adjustong finer


Sorry if I wasn't clear...but that is precisely the issue. If I make it finer, the grinder can't grind the beans. If I back it off a touch till I get it to grind, then the resulting grind is too coarse to get a decent extraction.

I wasn't leaving it running while adjusting the grind setting though, as @MediumRoastSteam suggested so I will try that when I get home.


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## Rob1 (Apr 9, 2015)

If you don't leave it running you trap bits of coffee between the burrs and the grinder will stall. Empty the hopper and you'll be able to adjust it finer no problem. All grinders need to be adjusted while running.


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## urbanbumpkin (Jan 30, 2013)

Rob1 said:


> If you don't leave it running you trap bits of coffee between the burrs and the grinder will stall. Empty the hopper and you'll be able to adjust it finer no problem. All grinders need to be adjusted while running.


What this guy said^^^^^


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## El carajillo (Mar 16, 2013)

Rob1 said:


> If you don't leave it running you trap bits of coffee between the burrs and the grinder will stall. Empty the hopper and you'll be able to adjust it finer no problem. All grinders need to be adjusted while running.


But do not go too fine!!!! The burr's on the Ib M 2 are conical, if they touch while running they WILL lock up and strip the drive gear or motor:eek:


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## Mrboots2u (May 10, 2013)

A properly functioning inbertal, in theory should have no problem grinding the crank house.

Whats is too quick to your right shot.

What dose and weight out of espresso is the grind setting making in w ha t time.

You are weighing in and out...


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## dsc (Jun 7, 2013)

El carajillo said:


> But do not go too fine!!!! The burr's on the Ib M 2 are conical, if they touch while running they WILL lock up and strip the drive gear or motor:eek:


Wouldn't recommend this either, but the burrs shouldn't lock even when touching. There's a smooth thin section on the bottom of the inner burr which should simply rub against the outer burr surface even if you get both parts too close.

T.


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## El carajillo (Mar 16, 2013)

dsc said:


> Wouldn't recommend this either, but the burrs shouldn't lock even when touching. There's a smooth thin section on the bottom of the inner burr which should simply rub against the outer burr surface even if you get both parts too close.
> 
> T.


Happy Donkey who sell these warn about this problem and if you do lock the burrs up it is not covered by warranty.

I have repaired 3 of these where the drive gear teeth have been stripped:confused:


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## dsc (Jun 7, 2013)

Ah right, might be specific to the MC2 then.

T.


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## phollingswo (Nov 29, 2013)

Update:

So with much help from @El_carajillo, I decided to do a bit of maintenance on the grinder this weekend.

We suspected that it might have been some stripped teeth on the cog inside, so I ordered a new one, took the whole grinder apart, and set about giving it a good clean and make sure everything was properly tightened.

I'm not really that experienced with taking this sort of thing apart, but once you get your head around how it all fits together, and so long as you take some pictures so you can see what order things go back together, it's fairly straight forwards. The hardest bit was getting the little nut holding the burrs together undone. You have to keep the lower burr in place while you undo the nut (which is reversed threaded). I found that using some electricians tape to keep it protected, and then holding it steady with an adjustable wrench, worked in the end.

There was a lot of coffee grounds that were clogged up around the burrs, so it clearly needed a good clean. I switched the motor cog over to the new one, although the old one didn't look like any teeth had been stripped.

I put it back together, but the same thing happened! It will grind a few beans at a time if you put them in slowly, but if you try to put in 20g of beans into the hopper, say, then it just get's jammed and then won't grind any more. However it looks as if it may be the grounds getting clogged up in the chute area, and where the sweeper blade things are, as it just seems to fill up there, rather than coming down the chute. So I'm not sure if there's like a really severe static issue or something else?

For now, I'm just grinding a handful at a time and will probably just use this batch for V60 or aeropress, and then go back to the CH8 which the MC2 had absolutely no issues with. Something about this particular batch it just can't handle.


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