Elektra Nino Grinds Through Rock--Request For Help From K10/M7KR Owners - Page 2

Grinders are one of the keys to exceptional espresso. Discuss them here.
andy_P

#11: Post by andy_P »



Thought I'd post a close up of one, in case it helps. I can't tell the difference between this and the output from your Nino, to be honest.

User avatar
shadowfax (original poster)

#12: Post by shadowfax (original poster) »

Andy, thanks for the photos! It's good to have an additional point of reference. Indeed, your photos look pretty close to my original photo--hard to say. Certainly close to what I am seeing today. I'd imagine there's a good chance that the 'test' that worked well for the damaged Vario may not be applicable in this situation. I think your photos point to that. Now I'm curious to see a particle analysis of a Nino at espresso grind...

Anyway, I pulled the burr carrier this evening and did your eccentricity test, Jim. I think the Nino passed. I didn't get 100% transferral from top to bottom burr, but it wasn't a lop-sided transfer--just a couple patches where I must not have put enough ink on to transfer, maybe? That or one of the burrs isn't perfectly round. :lol:

I'm getting a large quantity of coffee to do some better testing tomorrow (and a fellow taster to help!), so I'll follow-up with that. Aside from that, I probably won't have any real answers till I get new burrs (if then). Thanks for the help so far, guys!
Nicholas Lundgaard

Cerini Coffee & Gifts: official US importer for Olympia Express
Sponsored by Cerini Coffee & Gifts
User avatar
gyro

#13: Post by gyro »

Grinder woes, I know what thats about!

From my experience with the defective burrs on the Robur, I say trust your instinct on it. If you think you have chewed a rock and its thrown things off, then my money is on that being the case.

I might offer a suggestion though before you spend the money on new burrs. Give it a chance to 'wear in' again for a while. If a new imperfection in the burrs is giving grief, let it be worn down through usage for a while and it will possibly settle back down to its previous performance. I think it could be akin to the initial break in whereby any excessively 'proud' surfaces are worked harder and brought into line through use. If its a relatively minor imperfection, then this should not take too long. Major ding and that could be another story completely. My first set of burrs were so beat up, despite being new, that it would have taken forever to get a decent grind out of them.

For what its worth, heres a photo of my second set of Robur burrs. A reasonable ding on them that after a little use (maybe 5 or 10lbs) wasn't really causing anything significant. I believe this was just a manufacturing fault or perhaps done on installation, who knows. I am pretty sure its not been from a rock.



Good luck, Chris

User avatar
another_jim
Team HB

#14: Post by another_jim »

shadowfax wrote: Anyway, I pulled the burr carrier this evening and did your eccentricity test, Jim. I think the Nino passed. I didn't get 100% transferral from top to bottom burr, but it wasn't a lop-sided transfer--just a couple patches where I must not have put enough ink on to transfer, maybe?
Yep, that's a pass. BTW, the test is by Michael Teahan of Espresso Parts Source, something he recommends before ordering new burrs (did I mention he's a class act). It means you need new burrs if the grinder woes don't go away.

I have to admit to eating crow here -- I never suspected a few burr imperfections, creating a low proportion of malformed grind particles, could screw up the puck geometry enough to affect the taste. I guess the best person to explain it would be a road bed engineer, since they know all about packing together irregular objects.
Jim Schulman

User avatar
shadowfax (original poster)

#15: Post by shadowfax (original poster) »

Well, many thanks to Mr. Teahan for that clever idea.

As far as "a few imperfections," how many is a few? There are only a few notches that I can see easily (and that stand out in the photos I've shown you), but the burr also seems littered with dulled or rough edges down many of the "medium-fine" cutting ridges: Looking at a picture doesn't do justice to rotating the burr in your hand with a flashlight pointed at it, and even doing that isn't likely to show all the flaws that might/might not be there. Some of it probably is expected, right? I mean, my understanding is that at least some of the seasoning process is dulling excessively sharp burrs. But how much dulling is good? I don't think my Robur burrs looked anything like this after months of usage. Heck, the top burr looks dramatically better than the bottom one (how does that work?).

My friend Paul and I are going to pull his Robur E's burrs tomorrow and put each set under the magnifying glass.

Finally, after my own jumping to conclusions and being tempered by all of your voices of reason, I am forced to admit--I still can't rule out every single possible cause. I've had (very mild) cold symptoms this week, I've been using coffee that was frozen for at least a couple weeks in sealed mason jars (is my freezer not up to snuff for storage? Are Jim and Ken pulling our legs on that freezing thing?), etc. A friend of mine asked me, Are you sure the rock happened a week ago? How do you know your grinder didn't come that way? All of my experience (and rationalization of it) so far points to a week ago, but I have no concrete evidence to say that Elektra didn't ship me a grinder with a damaged bottom burr, and that apparently this is minor damage that's been there all along, and my weeklong rut has to do with something I haven't even considered yet. I think that sounds like a load of BS, but I can't refute it with much more than scoffing--yet.

Obviously more experimenting needs to be done, and of course as Chris Tacy said, I really won't know if the burrs are the problem till the new ones come in and I get an epiphany. You don't have to eat the crow just yet, Jim... I'll keep it in the fridge for you. :P
Nicholas Lundgaard

User avatar
shadowfax (original poster)

#16: Post by shadowfax (original poster) »

Moderator note: Discussion of grinder burr manufacturing defects/quality control split to Poor Grinder Burr Manufacturer QC; continue reading...
Nicholas Lundgaard

User avatar
Sherman

#17: Post by Sherman »

Out of curiousity, what exactly is this "eccentricity test"? Based on context, I'm assuming that it has something to do with making a mark on the burr, then turning it, but that's about all I'm getting out of it. Care to provide more detail?

-s.
Your dog wants espresso.
LMWDP #288

Decent Espresso: espresso equipment for serious baristas
Sponsored by Decent Espresso
User avatar
shadowfax (original poster)

#18: Post by shadowfax (original poster) »

The eccentricity test is to make sure that the top/outer burr is aligned with the bottom/inner burr when mounted in the machine. If the bottom burr isn't centered perfectly in the center of the top one, then the grind quality would be significantly compromised.

So you make a ring of wet, washable ink on the top burr, and screw it down till it just begins to touch the bottom one. If they're aligned, it will make a proper ring of ink all the way around the bottom burr. If they're not, then you'll see that the impression of ink is only on one side.
Nicholas Lundgaard

User avatar
cannonfodder
Team HB

#19: Post by cannonfodder »

That will make one side of the burr set grind finer than the other and give you a very wide variance in partial size. You have a very expensive blade grinder. It will produce large chips and dust at the same time instead of a relatively uniform particle.
Dave Stephens

User avatar
dsc

#20: Post by dsc »

Hi guys,

what ink do you use? I tried this test a few times, even on my Major, but had problems with the ink drying out before I could screw the upper burr in. Would an uneven layer of ink cause bad results? I believe the burrs behave differently when moving (sort of levelling on their own) and when stationary, so that can affect the test.

Anyone tested grinders which 'failed' this test, yet still produced proper grind for espresso?

Regards,
dsc.