I am trying to adjust the zero point of my K30 Vario because it doesn't grind fine enough. The manual includes these instructions:

9.3 Recalibration of the grind adjustment
Due to wear and tear fo the grinding discs or after exchanging them the Zero-grind-adjustment has to be recalibrated.
• Turn the grind adjustment to the finest setting "0".
• Close and remove the hopper.
• Remove the remaining beans from the filler shaft and vacuum out the grinder casing.
• Remove the silicone sealing ring from the filler shaft.
• Loosen - do not unscrew - the adjusting screws with the included Allen key (size 2.5, article No. 6568 - also available in service-kit).
• Insert the adjusting handle (service-pack) into the filler shaft. The adjusting handle must engage in the slot in the filler shaft's transverse biar.
• Start the grinder.
• Whilst the grinder is running, turn tihe adjusting handle clockwise until a slight ringing sound becomes audible. Now turn the adjusting handle back anti-clockwise until no further ringing sound can be heard.

Unfortunately there is no diagram identifying all the parts. I can get as far as removing the silicone gasket, then the instructions are a little confusing. There are no allen key screws, but there are two flat head screws. Have these been substituted since the manual was written?

I also have no idea what they mean by "the slot in the filler shaft's transverse biar". There is a little shaft sticking out into the throat, but there is no slot on it.

Service, Parts & Technical Support:
MAHLKÖNIG® USA, Inc.
5353 Scotts Valley Dr., Suite B
Scotts Valley, CA 95066
Toll Free: 866-EZ GRIND (394-7463)
Phone: 831-438-9800
Fax: 831-438-980

Chris, I've sent you an email with the K30 manuals.
The adjusting handle was obsoleted and discontinued (its not necessary).

Remove the restrictor screw from the side of the lid, and adjust to zero to remove the lid (it just lifts off)
When you have the top off, adjust the upper burr carrier finer by hand until burrs touch (not running).
Then make a small offset (loosen the adjustment slightly) and replace the lid.


Also - some of this stuff is easier to find at the Ditting website.

Thank you for the manuals, Jon. From what I can tell based on the service manual and trying it just now, the lid can only be removed with the grind adjustment at the coarsest setting. This makes it more difficult to zero the burrs, since it can't be done directly at the fine setting with the lid off.

For a straight burr replacement, the service manual says to find the zero point, back off a little, then back off another 90 degrees to compensate for the adjustment being at the coarse end. Then it says to do the actual fine zero calibration with the lid on as described in my first post. I can see this is done as I expected, but the overall process I described correct?

Bob_McBob wrote:Thank you for the manuals, Jon. From what I can tell based on the service manual and trying it just now, the lid can only be removed with the grind adjustment at the coarsest setting. This makes it more difficult to zero the burrs, since it can't be done directly at the fine setting with the lid off.

You do find the zero with the lidd off, then mark the 90 degree range on the carrier so you can move to the coarse setting to replace the lid.

Bob_McBob wrote:For a straight burr replacement, the service manual says to find the zero point, back off a little, then back off another 90 degrees to compensate for the adjustment being at the coarse end. Then it says to do the actual fine zero calibration with the lid on as described in my first post. I can see this is done as I expected, but the overall process I described correct?

The process you describe accurately reflects the manual instructions, but there is no point in actually doing it. They only give you a tiny range on the slots for those screws, and in the end it doesn't matter because you never need to adjust to the true zero point.

When I refurbished my old one, I just did the bit where you find zero and back off a bit and then mark the range and replace the lid. the fine adjustment you describe is to account for variance in the end position of the notches for the lid pegs and in use this will never be material to your results. There is plenty of adjustment range without having zero on the marker ring be absolute true zero.

EDIT - in my anal nature I decided instead to calibrate the adjustment setting so that the sweet spot for me was close to the middle of the adjustment range, to get the most useable range possible (even though I would only adjust a very small amount either direction from my sweet spot)

Mine isn't the Vario version but under the lid I think the mechanism is similar to the ES model. With the lid removed (one screw on ES) the upper burr carrier can be adjusted very easily by hand - counter clockwise (loosening the burr) increases grind size while tightening the burr clockwise decreases grind size.

I first set one of the shot timers to 10 seconds so the grinder would stay running while holding the button in with my finger. Next I removed the top cover. The upper burr is exposed and turns easily - I wanted a finer grind so I tightened the burr a couple cog notches and reinstalled the cover. I started at the largest setting and found "zero" adjusting slowly to where the burrs make the faintest chatter (the whir will take in a metallic sound - you can't miss it).

This point did not match a spot between one and zero on my adjustment slide so I took the cover off and adjusted a bit more - took a couple adjustments but now my burrs make the touching sound between 1/2 and 0 so I can grind finer than my machine can push water through.

Only tool needed was a screwdriver - and though it is not necessary to remove the upper burr this is a good time to check out the heart of this grinder - the shiny burrs are beautiful to behold.

I thought I would add an update to the adjustment process - I went to Lowes for some lumber and picked up a set of Kobalt brand Allen wrenches for $4. FYI, the portafilter holder adjusts with the #3 wrench.

To adjust without removing the top cover: Remove the hopper, empty the grinder, and set the adjustment to zero. Next visualize the two Allen screws inside the throat on the upper plate and loosen using the #2.5 Allen wrench. After loosening these screws in the throat of the grinder (where the hopper rests) fingertip pressure on the side of the two steel pins visible lower in the throat (found on either side of the throat on the lower layer of metal that is a lighter color) can turn the lower throat collar clockwise and counter clockwise.

Since you want to turn these while the grinder is running fingertips are not recommended. I used a pair of pliers with rubber coated handles. The handles fit in easily and rest on the side of the pins and allow for adjustment. With the grinder running slowly, turn the pliers clockwise till you hear a slight chatter and then lift the pliers and move the handles to the other side of the pins so you can back it off just enough to stop the chatter. the adjustment is zero now at the zero setting on the dial.

Re-tighten the two Allen screws in the throat and replace the hopper. No proprietary tools are needed and the top cover remains attached through the process.

Thank you everyone who replied with tips, especially Jon for the service manuals. I had the grinder open and tried to make an adjustment, but seemed to end up at the same zero point as the intial factory setting when trying to screw down the burrs until they touched and backing off a little. I found it pretty difficult to rotate the burr carrier. Are you supposed to unscrew the collar surrounding it (three screws)?

I am able to use the grinder with my Duetto and VST basket, but the typical setting is around 1-1.5 with an 18g dose, which doesn't leave a lot of wiggle room. I'm only running the pump at 8.5 bar right now, so it would be even closer if I increased the pressure. I am going to have another go at it on the weekend.

Side note: My K30 Vario, manufactured 10/10, has all the hex screws replaced with flat headed screws. This is one of the reasons why I was confused by the manual in the first place, since the grinder actually still comes with a set of hex keys, but I couldn't find the hex screws it was referring to all the time.