KitchenAid Pro Line Burr Coffee Grinder - Inside look

It was past due time to clean my coffee grinder, so I took this as an opportunity to take some photos. Besides its more fun to see a dirty, crudded up grinder before its been cleaned than afterwards. Seeing close up pictures is a reminder of how dirty things can get, a reminder to clean up more often.

I have owned this Kitchen Aid grinder for years. The body and motor feel built, when grinding beans it is not loud and never seems to be strained, as if the motor is overrated for the job. Static has not been a problem, during the height of winter I do notice a slight tendency for ground coffee to stick to the underside of the ground opening, which later drops off creating a mess on the counter, but its not too bad. But overall there is no static or clumping issues as the machine is mostly metal and glass. It features 57mm flat burrs and 15 stepped settings. Seeing close up photos of the burrs made me question whether they are starting to get worn.

If I tried to summarize the consensus opinions on the internet, it's that this is a middle of the road grinder, capable of both french press and espresso but not ideal for either. I may be influenced too much, but I would generally agree with that comment. The baseline set point of the grinder can be manually adjusted to bias the grinder towards the upper end (press) or lower end (espresso) of the grind range. I never did adjust mine as I wanted to switch back and forth between the two, but as I write this I plan to reset for an espresso bias. I have been grinding on the lowest setting and feel I need to go a step or two smaller to improve my espresso.
 
Fits well on the counter top, with a narrow profile up front:



Front dial showing the stepped grind settings from 1 (press) through 8 (espresso), with click steps every 1/2 point between each number:


Side view. The toggle switch is the only power control:


Difficult to see, but underneath the 6 o'clock position of the bean hopper is the auger which draws the beans into the burrs


Hopper starting to fill with beans. Add a little more and there will be enough to brew a 6 cup (3 mug) drip pot. A ridge is created at the point where the glass hopper screws onto the input feed, this is where beans can get hung up. A shake or slap on the side of the hopper is usually enough to coax any that want to hang on:
 
Its very easy to loosen the thumb screws holding the burs together. Pulling of the floating front burr gives this view:


Closer look at front half of burr set that is removed:


Looking back down into the bean hopper from above, can see the opening where the drive shaft (auger) is inserted into the motor drive


Another look at the front end:


Front end comes apart without any tools. The floating burr on the right sits directly on top of the adjustment mechanism shown on the left:


Couple of old stuck beans in the front burr:


Underneath view where ground coffee exits:
 
To demonstrate the ouput, I ground some stale, over roasted decaf coffee that I could not drink. Even with a dime coin for size reference but I find these pictures hard to judge and keep in perspective.

Setting 8 - Finest.


Setting 4.5 - Medium


Setting 1 - Largest
 
Nice pictures David. How frequently do you clean your grinder?
I usually clean it ever month or so, at least a quick clean to get most of the grounds out. But this time at least 4 months had passed before opening.

Wow, size 1 is gigantic. What would you use that grind for?
Agree. I have never used that size which is why I thought it curious that it would have specifications to go so wide. My burrs may be getting worn down which is allowing bigger pieces through, but in any case those would be too large for about any brewing method.
 

gearchow

Moderator Emeritus
David, really awesome pictorial. Couldn't that largest grind be ok for a French Press? I haven't used one in years, but I (seem to) recall a larger grind was appropriate.

How sharp are the burrs?

-jim
 
That is the exact grinder I have been using for the last 3 years. I don't take it apart and clean kt as often as you do but have never had any issues with it. I don't do espresso, but it's perfect for my other various brewing meth
 
That looks like a really nice grinder. I love Kitchen Aid products, they just seem to build them to last. Thanks for the breakdown shots.
 
Regarding the coarsest setting #1, I have used it to make cold brew coffee. When making french press I use a few clicks finer. But take my french press brewing comments lightly, as the last couple of times I made a press pot they were average at best. I didn't get the brew temps, grind size, dwell time, etc dialed in properly before moving on to a different method.

Regarding burr sharpness, they the feel smooth to the touch on the topmost surface - the high flat spots on the outer side of the burr face. But the beans would surely be crushed as they passed through the groves below the face. I cannot remember or give any feedback on how they might have felt when brand new, about how sharp they may have felt.

There is a stepless mod, I have not looked into the details but it involves wrapping Teflon tape around one of the plastic gear wheels so that it no longer engages or catches against the other gears which would then give it the individual steps. Where the tape is needed to provide enough friction to hold the adjustment setting. The plastic gears can be removed altogether but then there is no mechanical force to keep the grind setting constant as the machine vibrates. I like the stepped settings, but would like more. It has 15 steps but IMO 30 or more would be better when playing around at the fine end of the grind scale.
 
It really is hard to judge scale even with the dime in the pic, but still that doesn't look fine enough for great espresso.
 
It really is hard to judge scale even with the dime in the pic, but still that doesn't look fine enough for great espresso.
Yes and no. I have gotten some good tasting shots with my lever and presso, but on the few occasions I tried one ground coarser than finest I could see it was not improving and heading in the wrong direction. My sense has been that the grind size was close but would benefit from one step finer (at least). I have been accepting the finest setting as is while playing around with other variables, but it is time to step the grind down a notch or two. So in that sense I believe you are correct.
 
I don't mind stepped, but I agree - 30 would be more like it. My Vario has 40, and I've learned to float between two or three of those notches to compensate for freshness and volume. I don't know what I'd do with only 15 (which is why I mentioned the mod).

There's an even more pertinent mod, if you're set on keeping that machine, where you can put some serious burrs in that bad boy (from the Mazzer, IIRC).
 
My immediate plan is reset the burr adjuster to get the finest ground possible. If that goes well but I can't seem to get proper fine tuning between the steps, try the step-less modification. When I first got this grinder I drank mostly drip and the occasional french press, but now half the time its espresso or a close approximation. To that end, I've ordered a nice hand grinder that will likely take over the espresso grinding task. But a burr upgrade on the Kitchen Aid could be useful for the long haul.
 
It took just a few minutes to reset the burr gap down to its minimum setting, I should have done that long ago. On the finest setting, I believe I now get about 1.5 to 2 clicks finer grinds than before. When testing with the Presso machine, the finest setting seemed too fine, and it was too difficult to pull the shot. Adjusting one click open was better and is likely be my new preferred setting for that brewer, while also using a couple less grams of coffee.

I have a bit more appreciation for the machine's design after looking inside. From the outside the black dial is easy to read and sized to fit one's hand. The steps have a positive engagement, where one can both hear and feel the steps. One could easily adjust the grinder blindfolded and not have any doubts about what was going on. On the inside, the adjuster uses a pair of spring load pins that engage into the gaps of the plastic dial. One can see how user ergonomics on the outside, influenced the size of the toothed dial and the fineness of adjustment steps inside. If I could request an enhancement, it would be for Kitchen Aid to have made the thread pitch on the adjuster bolt finer so that each click moved the burr less distance and used all 360 degrees of the adjustment dial face in order to double the number of steps across the same adjustment range.

Picture of the adjustment dial. As you would expect, each tooth is one step:


Closeup of adjustment wheel and spring loaded pin. One could easily imagine wrapping tape around the back side of the wheel to provide a flat surface in order to counter the tendency for the alignment pin to self-center back into a tooth opening.
 
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