Burr alignment and symptoms?

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

Postby pcrussell50 » Mar 13, 2019, 2:54 pm

So in recent years, talk of burr alignment has been a thing. Enough so that for some grinders, it's even a selling point (Monolith).

Back in 2012-14,15 time frame, it seemed to burst into the HB scene with the HG-1, when people who were getting consistently ugly, spritzy pours began to suspect burr alignment. (I never had that problem with mine, but I only use it on a direct lever, or maybe I got lucky.)

So fast forward to today. For no reason other than time and interest, I've started thinking about it again. Not sure why. My pours look fabulous and my espresso tastes good. But... could it taste better? I don't really have any convenient way to tell. And I don't want to just buy a Monolith on a hunch.

So I'm looking for generalizations, if such exist. For example, is it safe to say that if you get good looking pours with no obvious and intransigent taste flaws, that further alignment is a case of diminishing returns? Or is that clearly NOT the case?

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Postby Jake_G » Mar 14, 2019, 8:14 pm


I just replied to Sam's post on EY and taste and think it hits on this question.

Why TDS/extraction yield measurements are not a good way to evaluate taste profile/quality?

Feel free to carry on this discussion right here, but I didn't feel like double-posting :D


- Jake


Postby nuketopia » Mar 15, 2019, 2:45 pm

Theoretically (since I cant prove this) the alignment of the burrs affects the distribution of particles in the grind. It makes sense, from a cause and effect standpoint, that particle size distributions that are more focused will produce more even extractions. More even extractions have been shown to produce higher extraction ratios, which is generally a good thing.

It has been shown the EY% and subjective quality of beverage varies among different grinders and it does correlate with the particle size distributions, with grinders producing distribution graphs with more modality generally doing better than those with lots of random particle sizes.

If you have tools available, like a refractometer and your workflow is repeatable and accurate, objective measures can be made.

I can say that my Monolith conical produces great tasting coffee and I've measured the TDS/EY% on many occasions and it is consistently capable. Denis (of Kafatek) does this along with a report with each grinder.

I do know that the large burr flat grinder I was using prior did have some alignment issues and it couldn't produce as high of EY and it had "repeatability" issues from cup to cup.

Since you're happy with what you got, there's no need to go mucking around with it. You may well indeed, have a well aligned burr set right from the box. If it ain't broke, don't fix it.

You can always test the theory when you open the grinder to clean it. All it takes is a whiteboard marker and a little time.


Postby blkswn » Mar 15, 2019, 7:55 pm

I'll chime in on my experiences just based purely on taste and preferences. Keep in mind I single-dose most of the time.

I have a ceado E5P(64mm flat burrs) and mahlkonig EK43(98mm flat burrs) that were both purchased stock. The stock E5P routinely gave me clumped grounds, spritzing and channeling so I naturally tended towards grinding on the EK43 whenever I could. After aligning the E5P burrs it made a noticeable improvement in taste and significant change to grind settings, but I still preferred the EK. I swapped the E5P burrs for SSP's and installed them as-is and it was matching close to the EK in taste. For a while I was using the SSP burrs over the EK for light roasted espresso, even when the EK was aligned via marker method and foil shims.

A month ago I sanded the EK chamber and had the burr carrier machined to 0.000mm runout at a local shop and now my burrs sit in perfect alignment. The EK espressos were great to begin with but when aligned like this, with the same roast dialed in, it was tasting, to my surprise, noticeably sweeter. Now I prefer the EK shots over the SSPs. The EK grinds don't give me issues with channeling or spritzing, but each alignment method noticeably improved taste. Going through the EK alignment process, I wasn't fixated on getting better tasting coffee but rather the idea of taking out one less variable in my brew process and if it improves flavor, then good. The E5P had good shots with the stock burr, but after aligning it I liked it a lot better.

In my mind, it's like comparing a double shot americano with 6 oz hot water vs 8 oz hot water. Slight variances, but the tastes are different. 8 oz might be good but 6 oz lets you realize the 8oz is a bit watery and slightly more lacking..(not saying 6 oz is better, just using analogies to make a point)