Elektra Nino Grinds Through Rock--Request For Help From K10/M7KR Owners

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shadowfax

#1: Post by shadowfax »

Yes, my Nino has apparently pulverized a rock or other foreign object. I couldn't say how, I didn't even notice it happening. It didn't bind the machine, and apparently either didn't happen when grinding for a shot, or ground powder into a shot that was a similar color to the coffee beans.

This all started for me last week, with Intelligentsia's La Tortuga Honduras--my friend happened to be in LA recently and picked up a pound of that and Los Inmortales from Intelly Venice. We pulled shots of La Tortuga on his setup, and I had a baseline for what it was like--a pretty nice butterscotchy shot. Anyway, I took my part of that coffee home and had a tough time getting anything beyond "just drinkable" on my machine. I couldn't get the butterscotch at all, just kept getting this really messed up, funky to downright awful acidity to the shot.

After a half a pound of frustration, I started paying much closer attention. One of the first things I noticed was that my pucks looked rather... inconsistent. I checked the burrs, but I only looked at the top burr set. It looked to be in basically perfect shape, and at a glance the bottom/inner burr looked fine. Well, a whole run-around later that involved finishing the La Tortuga and the Los Inmortales as well, I came back to the grinder burrs again and actually pulled the bottom burrs... wow. They looked pretty rough!

Here's a sample of the "rough pucks" I was seeing that raised my eyebrows, and a comparison photo:


Sample from a still-damp spent Nino puck, looks kind of "rough" (Flickr link).


Old photo of spent dry Robur puck (left) and damp Vario puck (right), for comparison (Flickr link).

That second photo is from the Vario First Look thread, where I discovered that my Vario test unit had defective burrs/burr mounting, which produced the pucks on the right which were resulting in bad pours with a number of coffees. The Nino's puck is not quite that dirty, but it's definitely nowhere near the Robur's evenness. Sadly I don't have an old picture of a puck from a Nino in good order, but I am assuming that it ought to look something much more like the Robur's, overall.

Anyway, Here's my notched bottom burr:


The ugliest of the notches, lower right; you can also see the slot cut in the bottom burr to align it with the shaft. Does the K10 have this? (Flickr link)


Another angle of the bottom burr (Flickr link).

There are several really nasty notches here and there, and it's hard to assess it beyond that, but I get the impression that there may be more issues with the burrs than just the easily visible "wounds."

Anyway, 'absolute' confirmation of how much or a problem this turns out to be is still pending. I have experienced this problem on highly regarded but unfamiliar coffee, so tomorrow I'll be doing some side-by-side testing with the Baratza Vario (kinda sad I sold my Robur like a week ago, huh? :roll:) tomorrow using some black cat that should be right in its prime.

However, regardless of those results I need new burrs, and that's where this gets a little more complicated. As far as I can tell, no one in the US "actively" stocks Elektra Nino-branded burrs. Site sponsor Pasmarose does, but they are in Germany and I am not sure of shipping (still waiting to hear back from them)--I assume it will be pretty expensive on top of a set of burrs that are quite expensive themselves ($~175). I contacted 1st-line, the only US retailer that sells Ninos that I am aware of, and they don't currently have any spare burrs in stock.

Now, there are obviously a lot of other 68 mm conical burr grinders on the market--the Macap M7KR, Compak K10, Fiorenzato Doge, etc. The burr sets for these grinders look visually identical: same number of major and minor cutting edges, same overall look, and as far as I can tell, the same general measurements. However, there are some details to my Nino's burrs that may be unique, and I can't tell from the pictures I've seen of other 68 mm burrs to know if they match. I've sent an e-mail to Elektra asking about it, but I'm also making a call to all HBers with 68 mm conical grinders: If you have a set of calipers and a DIY attitude, I need to confirm some burr details that will require you to remove the mounting bolt from the bottom burr and the separate the top burr from the burr carrier. I'm particularly interested in the Compak K10 burrs, since I think I'll have the easiest time getting those.

Here's a rundown for my Nino: I am reading 68mm OD on the upper burr, 49mm OD on the bottom burr, height of each is 25 mm. There are 4 screw holes on the top burr, and it also has a 1.5mm x 1.5mm squared off indentation around the top where it mates to the carrier; the bottom burr has a 13mm hole for mounting, with the aligning slot being about 3mm wide. You can see the 3mm slot in the photos of the bottom burr above; here's what the indentation looks like on the top burr:


The indented cut along the top to fit in the top carrier (Flickr link).

Thanks in advance for anyone's willingness to have a look at their grinder and confirm any of these measurements/features. If you feel like taking pictures, especially if you find any differences, it may be good for posterity if you post them as well.
Nicholas Lundgaard

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andy_P

#2: Post by andy_P »

Sorry to hear about your grinder problems. I will check my Nino's spent pucks this evening but I do remember being surprised at the uneveness of the grinds compared to my Mazzer Mini-E when I first acquired the Nino - I just put this down to the conical / planar difference.

Could the variation you are noticing in grinds have anything to do with the upper burr carrier wiggle - I have wondered from time to time whether this might affect grind quality?

Good luck with finding replacement burrs.

Andy.

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dsc

#3: Post by dsc »

Hi Nicholas,

well I've already said this but 'shite this isn't good'. There, I've said it again.

Am I correct to think that the fine grinding happens near the flat section where the tiny ridges are on the outer edge of the burr? Isn't the rest there simply to make the beans smaller and smaller each turn until they are small enough to be turned to 'dust'? If that is indeed true that damage shouldn't really change anything, well at least shouldn't be the reason of getting bigger particles in the grind and inconsistency.

Please feel free to smack me across the head if the above is rubbish.

Regards,
dsc.

portamento

#4: Post by portamento »

Sorry to hear about that... very frustrating I'm sure. Especially since you are not sure exactly when and how it happened.

Have you tried returning to some baseline coffees that you are very familiar with, taste-wise? The single origin was new to you, and Black Cat has been going through frequent changes (recently adding in some of the Honduras).

It might be worthwhile to get everything assembled again and try calibrating just on taste.
Ryan

ira
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#5: Post by ira »

FWIW, your burrs don't look that much worse that the set of brand new Robur burrs I have sitting here.

Ira

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shadowfax (original poster)

#6: Post by shadowfax (original poster) »

Ira--nice one. I've followed up on that Robur issue with you privately just now, but at least I can say, I'm not sure that's evidence my burrs are OK.

Ryan--actually, my Black Cat was frozen for over a month, and is part of a kilo that I ordered in June--so I have a reasonable degree of familiarity with this specific coffee, although obviously I'm throwing the efficacy of freezing coffee to preserve it into the mix here. In any case, I do see your point, which can be thrown atop another point--that the ~2/3 lb. of Blac Cat I had this morning wasn't enough to get both grinders dialed in to my satisfaction. So, I'll get some local coffee that I know better (and can get 2-3 pounds of easily) later this week and use it.

Tom--I am convinced that pinning the ultimate determination of grind quality on the finest cutting surface is an oversimplification of the grinding process. I don't have data to back it up (just my own reasoning), but I'd be glad to send some grind samples to someone to analyze rocked burrs vs. new burrs. More SEM fun, John (Weiss)?

Andy--I can't categorically discount that the Nino isn't "supposed to" make pucks that look like what I've seen, but I can tell you the results of my experimentation this morning:

Using my Black Cat Classic, I dialed in the Vario first, which took a lot of coffee; about half of the coffee that I have. Anyway, I finally got some pretty good shots coming from it, and turned my attention to the Nino, only to find that the grind setting had changed pretty significantly: I had to move it about 1/6th of a full turn coarser than where it'd been on Friday to get 30 second shots. Of course, this is a different coffee than before, so that is potentially a moot point. What's not a moot point, however, is that the mulchy pucks are gone. It'd be a stretch to say they look less consistent than my Robur puck above--they looked better than the Vario pucks. :roll: (and I do mean the GOOD Vario pucks, not the ones from my first Vario posted above).

Anyway, dialed in thus far, I am in "decent" range on both grinders, depending on your definition. I'm not seeing gross cup defects in the cup like on the Nino last week, but I'm also not getting a complex or interesting cup (which Black cat was last time I pulled it). I feel like I need to do more tweaking to get good shots, though, like I've picked the wrong dose (17g). Unfortunately, I don't have enough coffee to do so at the moment, so it will have to wait for a different coffee that I'll get much more of.

For now, I've just had the waters muddied severely. I'm wondering, could the rock have unseated the bottom burr in some way? Did it just need to be reseated? That would explain a lot of what's happened today, but it also seems unbelievable to me after removing and installing the bottom burr--it's perfectly flush on the shaft. It doesn't rock back and forth or anything when the bolt isn't holding it down.

Great, non-reproducible problems. I love the observer effect...
Nicholas Lundgaard

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another_jim
Team HB

#7: Post by another_jim »

Have you done an eccentricity test with a marking pen yet? My guess is that this is the likeliest problem, since it would mean you are getting a much wider overall distribution of grinds.
Jim Schulman

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dsc

#8: Post by dsc »

Hi Nicholas,

yeah it's a pain in the ass when no one had a similar experiance, you're there pretty much on your own.

Was the 'rock' completely destroyed in the process? I'm asking because it might have done some damage to the bearing which would make the burr wobble or at least move slightly when stressed.

I guess the only advice I can give for now is trying to forget what happened and simply try to dial the grinder by taste only. Another thing would be trying out the grinder on your friend's machine and/or using a different grinder to compare against.

Stay strong man!!

Regards,
dsc.

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shadowfax (original poster)

#9: Post by shadowfax (original poster) »

Jim, I haven't done the eccentricity test yet, but I am going to get a washable marker this afternoon during my errands. As I said, I'm beginning to wonder if it was off-center as you had guessed and has come back now (seeing that my pucks are "cleaner" now). I can't answer whether it was off, but I'll go ahead and see how good it is with the current mounting tonight.

Tom--there's no visible wobble to the shaft, looking at it with the bottom burr on or off. It's a perfect rotation as it spins down from full speed. If I push on the shaft with my hand, I can't make it budge in any way, and it turns perfectly smooth with my hand. I can't see any evidence of damage to the shaft or anything below the burrs. That doesn't rule out eccentricity, though, so I still need to do Jim's ink test.
Nicholas Lundgaard

andy_P

#10: Post by andy_P »





Here are a few pics of pucks from my Nino. The last two are spent pucks, the first is a pre-pull puck. They look reasonably uniform, at least a lot better than your faulty Vario's puck but not as uniform as the Robur's.