Acaia Lunar review: This $250 coffee scale isn’t for the faint of heart

The Acaia Lunar is one of the priciest, best-designed coffee scales available right now. The Lunar is an Acaia coffee scale, after all, so there’s no doubt about it: it’s going to pinch the trophy in the best coffee scales beauty pageant.

Unlike the Pearl S or the Orion, the Lunar is designed explicitly to work with the best espresso machines. Obviously there’s no stopping you using this for different brew methods — there’s even a pour-over mode — but the Lunar’s main focus is espresso. The tiny 6-inch size means it fits easily onto any drip tray, and even slots into place with the Orion.

But beauty doesn’t come cheap. It is an Acaia scale, after all. The Lunar will set you back $250, $30 pricier than the fantastic Pearl S. Could the Lunar be worth your dollars, though? Find out in this Acaia Lunar coffee scale review.

Acaia Lunar Coffee Scale review: Cheat sheet

• Who is it for? An espresso-focused coffee scale designed for a commercial environment, or home baristas who are really serious about brewing perfect espresso
• What does it cost? It’s an Acaia scale, so it’s not cheap — $250
• What does it do well? It’s not $250 for no reason: the accuracy is fantastic, the range of modes allows you to customize almost everything, and you get the usual library of Acaia specialty coffee apps
• What do we wish it did better? Sometimes the weight jumps around and, obviously, it’s really expensive

Acaia Lunar Coffee Scale review: Specs

Acaia Lunar Coffee Scale review: Price & availability

The Acaia Lunar is an expensive, premium coffee scale designed for commercial espresso use. It's $250 direct from Acaia.

Of course you don’t have to be a professional barista to buy it, but that’s who it’s aimed at. I was once a professional barista, but I worked in an environment too fast-paced to have time to use one — we had timers built into the espresso machines. The Lunar is best suited for an artisanal coffee shop that allows time for weighing, or a serious espresso home barista. I wouldn’t recommend it for a busy commercial cafe, however small artisan coffee shops and serious home baristas? Absolutely.

The Lunar is available in black, silver, cool white, beige white, and space gray. I tested the black version, which is incredibly beautiful. That’s where Acaia’s lineup really excels: its aesthetics.

Compared to other Acaia scales, the Lunar is the second-priciest. At the cheapest end of the spectrum, you’ll find the $150 Pearl, then the $220 Pearl S, the $250 Lunar, and the $270 Pyxis. For most at-home baristas, I’d recommend the Pearl S. However, if you want to save money but still get a premium product, you might be interested in the $110 Felicita Arc. The Felicita functions mostly the same as the Acaia: the only thing it’s missing is the live Brewmaster app.

Acaia Lunar Coffee Scale review: Design & functions

The Acaia Lunar coffee scale looks the part, that’s for sure. The compact 6 x 6 inch surface makes way for ultimate compatibility with espresso machine drip trays. It slotted perfectly into my De’Longhi La Specialista Opera machine during testing.

While designed for espresso machines, the Lunar isn’t just restricted to espresso. You can use this with some of the best coffee makers. There’s a pour-over mode as well as a range of espresso-forward functions. You can choose from weighing, dual display (manual timer), auto-timer, auto-tare, auto-tare and pre-infusion auto-timer, and pour-over. I mostly used pre-infusion auto-tare with my espresso machine.

I was disappointed to find that Brewguide, my favorite aspect of the Acaia Pearl S ($220), isn’t available on the Lunar scale. I understand why — the Lunar is designed for commercial use, by fully-trained specialty baristas, whereas the Pearl S is intended for home users — but I still would’ve liked to see a Lunar version of Brewguide. Even an app that links to the Lunar via Bluetooth and walks you through ideal espresso ratios would be great.

While there’s no Brewguide app, there is Brewmaster. Brewmaster is a little like Brewguide in that it helps you master coffee. It doesn’t teach you per se, unlike Brewguide, but you can log brews and track flow rate in-app, which will be handy for baristas.

The Lunar has really got me tracking my espresso pulls on graphs. As someone who loathed math at school, this is the first graph I’ve actually enjoyed analyzing. Not only can you track live flow-rates, you can also evaluate the espresso in the Brewmaster app. In spite of the mediocre beans I used, I thoroughly enjoyed tracking my brew on the Brewmaster app.

Acaia Lunar Coffee Scale review: Performance

For $250, you’d expect a precise, highly accurate, and well-designed coffee scale. Check, check, check. However, incredibly precise accuracy is the Lunar’s magnum opus and its Achilles Heel.

The Lunar is so accurate that its precision encroaches on usability. Sure, I want to weigh my espresso to 0.1 accuracy. However, this accuracy means that the weight jumps around and is really hard to pinpoint a specific weight. For example, when I was weighing my portafilter prior to dosing 18g of coffee, the weight jumped from 379.7g to 379.4g, which meant I had to wait this out in order to tare. Then, when I put the portafilter back on the Lunar to double-check the recorded weight, it showed -0.2g.

I repeated this process six times and never did the portafilter settle on a specific weight. This is a notable con for a professional-grade scale. As a result, the Lunar expects its user to invest in secondary equipment to make the most of it. Users would need a high-quality doser like the Acaia Orion doser or a grinder like the Eureka Mignon Specialita ($699) that can dose a preset amount of coffee straight into portafilters — because you can’t weigh with a portafilter on the Lunar. You can turn the heat-proof pad upside-down to weigh the portafilter more accurately, but Acaia has advised me that the Lunar is too small to confidently weigh portafilters.

However, this was only an issue for portafilters. When I placed my espresso mug on the Lunar, it immediately weighed as 193.7g. I was able to tare and go about my normal espresso process in seconds.

In terms of accuracy, the Lunar comes with a 100g calibration weight. I used this weight to calibrate the scale upon receipt.

Here’s a table of my weighing tests. All measurements are in grams, as grams is the standard coffee unit.

As you can see, the Lunar was mostly the same as the Acaia Pearl S. The Lunar weighs accurately and quickly. However, there were a few instances that were different, namely the first weight and the fifth weight.

Acaia Lunar Coffee Scale review: Storage & maintenance

As with other Acaia scales, users in the U.S. automatically receive a 2-year warranty with their new Lunar, which will give peace of mind.

Storage is simple: simply slot the Lunar in your kitchen drawer or wherever it fits within your coffee station. Given its compact size, it’s easy to find space to hide the Lunar away, not that you’d want to as it’s so beautiful.

The battery lasts up to 40 hours and is rechargeable by USB-C, so no need to worry about it running out of battery. Acaia warns against cleaning with chemicals, but as this scale is water-resistant, you’ll be able to wipe it clean with no stress.

Acaia Lunar Coffee Scale review: How does it compare?

If you’re desperate for an Acaia scale, I’d recommend the Pearl S. You can still use Brewmaster with the Pearl S, and although the Pearl S is much bigger than the Lunar, it still slots nicely onto an espresso machine drip tray. The Pearl S is just so much more affable and appealing.

If you want to save $100 but still want an effective espresso-focused scale, the IPX5-rated Felicita Arc ($110) could be a fantastic option. The Felicita Arc has most of the same modes as the Lunar, and a companion app, but there’s certainly less versatility with this app.

For those trying to save serious bucks, the Timemore Black Mirror Basic 2 is a fantastic scale under $60 with a live flow-rate monitor. Again, this has no app at all, but it’s a good entry-level scale with premium features.

However, if you’re a home barista determined to purchase an Acaia scale, I’d definitely check out the Pearl S instead of the Lunar.

Acaia Lunar Coffee Scale review: Verdict

When a coffee scale is priced at $250, there’s very little room for downsides. You expect a premium-priced product to perform well enough to justify its cost.

Yes, the Lunar looks gorgeous, and yes, it does function well. However, a commercial-tier espresso scale that can’t weigh portafilters is a missed trick. Every other scale I’ve used to weigh portafilters just work. Even Acaia’s own Pearl S can do it.

The Brewmaster app is a great little piece of software that makes every espresso pull feel alive, but you can use this with the Pearl S, too. The bottom line is this: the Lunar is good, but the Pearl S is better.