Lucca Atom 75 Espresso Grinder Review

Behind the scenes of the site's projects and equipment reviews.
User avatar
Team HB

#1: Post by another_jim »

The Lucca Atom 75 is the Eureka Atom 75 customized for Clive Coffee. The line of Eureka Atom grinders is a compact version of their on-demand cafe grinders, with the Atom 75 using a 75mm flat burr. The Lucca customization includes a broken in and cyrogenically hardened burrset, a sensor based grind adjustment system that is completely repeatable, and a wifi connected database for storing the grind settings and dosing of your different coffees and prep methods.

For the past few months, Dan and I have been looking at two review grinders, provided to us at no cost by Clive Coffee; and we will be posting our impressions here. I will be looking at how good this grinder tastes (spoiler: very good), its ergonomics as an on-demand grinder (spoiler: stellar), and as a single dosing grinder (spoiler: very bad).

Here's a casual cell phone video to give you a taste ...
This topics is for review material only; please post all comments in the comment thread. Thanks.
Jim Schulman

User avatar
another_jim (original poster)
Team HB

#2: Post by another_jim (original poster) »

Burrs and Taste

The Atom 75 uses one of the several 75mm burrs made by Eureka, and used in their 75mm grinders as well as in the Mythos line, which they manufacture. Clive coffee advertises this burr as already broken in and as cyrogenically treated, which makes it one of the premium choices normally used in the Mythos series.

In addition, the Lucca version of the grinder has an electronically measured and controlled grind setting. The new user runs the grinder in its calibration mode, tightening the grind until the burrs begin to chirp. The grinder shows this as the zero setting. This works very well. I removed the burrs several times, relaced and rezeroed them, and was able to return to my preferred settings, getting the same dose and timing. The flat panel display of the grind setting allows for very fine adjustments -- my fine espresso settings were around 40, and coarse settings were around 50.

So how do premium burrs and electronic adjustments work? Very nicely indeed. The blind comparisons done in single dose mode with five different light and medium roasted coffees were indistinguishable from the Niche Zero or other large conicals; and the "somewhat blind*" tests done in on demand mode slightly beat them.

What I cannot report is the famed flat burr effect of increased clarity and a smaller sweet for dialing in. Instead, this is one of the friendliest, sweetest, and biggest sweet spot burrs ever. That is especially true when using it in on demand mode. When the Mythos first came out, I spent an afternoon with it being seriously impressed in how fast it dialed in and how nicely it worked to fine tune the taste. Eureka has only improved on the burrs since then.

A close up look on the burr shows that there is a fairly large cut through on the outer edge. This may have something to do with the very conical taste these burrs give.

So, very fast dial in and a sweet, balanced taste yes; but the heavens open and angels sing shot clarity, no.

* Somewhat blind. In on demand mode, the hopper is on, and the grind is set on the Atom, and then I tried to get the same dose and grind on the Niche Zero. The tamping and distribution on the Atom in this mode is so effortless that getting an indistinguishable pour on the Niche was very hard. That made the shots only "somewhat blind," in that is was usually possible to guess which was which by the pour.
Jim Schulman

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

#3: Post by another_jim (original poster) »

The Lucca Atom as a Single Dosing Grinder

An on-demand grinder uses a hopper filled with beans to deliver a timed or weighed dose of grounds to a waiting portafilter or basket. It can be designed to "expect" a load of hoppered beans on the intake and a mass of ground coffee inside the grind chamber output. On the other hand, a good single dosing has to work with no extra -- the coffee in either the bean intake or the ground powder output. The Atom 75 is stellar in sucking in even single beans one at a time; but its performance degrades considerably on the output side when delivering single doses of ground coffee.

The secret of the great bean intake is an augur on the burr,

and a cover over most of the burr area to prevent popcorning. There is also a rubber seal between the upper place and the burr chamber

The superb intake engineering along with the large 75mm burr makes for very fast grinding. I use a 1.2 sec setting to get a 7.5 gram single, and simply hit that twice for a double. The pace is slightly slower when not using a hopper and just feeding in a single dose; but not by much.

The grind chamber exit is a different story. There is a long tunnel after the exit, leading down behind the control panel to the portafilter or basket. There is a grate at the exit. If the grind chamber is filled with ground coffee, the coffee squeezes through the grate like whipped cream through a pastry funnel, and there is no static, just a very neat pile in the basket.

If the grate is removed and the grind chamber is kept empty by using a bellows,

the grounds are staticky and come out in a spray. They stick to the the exit tunnel and spray all over the basket and counter, requiring RDT, WDT, and other contortions. Moreover, the grind chamber retains enough loose grinds to make the dosing slightly hit or miss as well.

This is one of the easiest and joyous grinders ever to use in on-demand mode, and it is a PITA to use as a single doser. So I recommend it wholeheartedly for on demand, and don't recommend it for single dosing.
Jim Schulman

User avatar

#4: Post by HB »

another_jim wrote:Here's a casual cell phone video to give you a taste ...
Jim has thrown down the gauntlet, challenging me to make a one-handed espresso prep video. :lol:

I accept the challenge, but first I'd like to provide some backstory for the Lucca Atom 75. It's a bit market-y, but this video from Clive Coffee explains the motivation and goals of the Lucca:
As part of the Newbie Introduction to Espresso - Grinders, I demonstrated a method of dialing in a grinder by touch; dialing in a grinder is also discussed in multiple threads:
And that's just a small sample! It's clear that Clive Coffee has accurately identified a common pain point for home baristas. :shock:

The popularity of dedicated single-dosing grinders (i.e., those without a hopper designed to grind enough coffee for just a single/double espresso) has helped reduce waste because the grind setting can be changed without "carryover" from the prior setting. But that really doesn't address one of the key problems, especially for less experienced baristas: What's the best initial grind setting?

I was a bit skeptical that a "smart" coffee grinder could make a decent guess. I've tried several coffees from light-medium to dark, very freshly roasted to 2 weeks out. The estimates from the TrueGrind / Lucca Atom 75 varied from spot-on to off by a few seconds of pour time. If you want to understand how it does it, check out the patent: Coffee grinder that automatically sets grind level. It boils down to an equation:
Patent US20210219782A1 wrote:34. The method ... includes calculating the burr gap setting (G) based on the following equation:

P Offset + W Bias + (W 58Basket × P 58Basket) + (W Capp × P Capp) + (W Latte ×P Latte) + (W DoR × P DoR) + (W Dose × P Dose) + (W Temp × P Temp)
As an aside, the above formula includes temperature, but the app doesn't have that as an input parameter. It does include roast level, roast date, coffee dose weight, target extraction weight/pour time, and beverage type.
another_jim wrote:This is one of the easiest and joyous grinders ever to use in on-demand mode, and it is a PITA to use as a single doser. So I recommend it wholeheartedly for on demand, and don't recommend it for single dosing.
I agree with Jim's assessment; the Lucca Atom 75 isn't a single dose grinder designed for frequently switching coffees. Trying to coerce it into that prep model would waste coffee since you'd have to add enough extra coffee to clear out the "old" grounds from the prior coffee, plus the lack of pressure from the bean column would reduce the accuracy of the timed dosing. On the other hand, as an on-demand grinder, it's ridiculously easy to dial in.

A usage reminder: If you haven't run the grinder in awhile, I recommend tapping the "quick purge" option:

The squiggle icon runs the grinder for 0.2 seconds or about 1.5 grams of coffee.

I've been loading the hopper with 2-3 shots worth of coffee and that's enough for accurate timed dosing. I typically make 3-4 espressos a day, varying in weight from 17 grams to 20 grams if the coffee is fading, so the net loss to purging is around 3% per day. Arguably that can add up if you're buying lots of coffee, but on the other hand, if the Lucca saves you from just one sink shot a week, you're ahead of the game. It will be interesting to see how well this theoretical savings plays out in real life; it's my guess that for an inexperienced barista, the savings in sink shots/aggravation will be non-trivial.

So, who should consider the Lucca Atom 75?

It's an easy answer: If you're the type of drinker who goes through one bag of coffee at a time, the Lucca Atom 75 will fit your preparation model very well and likely save you time/aggravation dialing in when you switch to the next coffee. I suspect it's not coincidence that Clive Coffee, designer of the Lucca Atom 75, is also owner of a personalized coffee subscription service, Mistobox (disclaimer: both are site sponsors).
Dan Kehn