November 17, 2015

The Acaia Lunar: Trendy Toy or Serviceable Scales?


The Acaia Lunar has been the darling of coffee feeds, blogs, and the third wave at large since its release. But is it all hype, or does it actually have use for baristas and coffee professionals?

Having used Acaia’s first set of scales, the Pearl, for group handles and as a platform for filter brews, I was excited to – pardon the pun – weigh up how well the Lunar operates in service. That last part is all that really matters to me. Unless it can provide a clear benefit to a barista, it has no place in a café.

SEE ALSO: Pressure Profiling: The Key to Perfect Extraction

On paper, it looks stunning: it’s highly water resistant, capable of having espresso run all over it if the barista gets distracted, has an update rate apparently second to none, and even auto-tares (determines the weight of a container).

Yet having used other scales before, only for them to fail or refresh at a painfully slow rate, I was apprehensive. Could the Lunar really be as good as it sounds?

Please note: this review is based on my experiences of the Acaia Lunar’s practicality at work as a barista. It’s focussed on the Lunar’s use at the front end of third wave coffee service and, as of such, is not a comprehensive review of all the product’s uses.

Testing Conditions

I tested the Lunar in the same café where I work. It’s a mid-volume cafe (around 6kg/day of coffee) that rotates through up to six different coffees on an Mahlkönig EK43 and a Mazzer Robur-E. For anyone who hasn’t worked in a café before, that means we dial in (determine the ideal grind size, weight of ground coffee used, and the liquid out) all of those coffees to find the best flavour.  Weighing in and out is something we consider a minimum standard since we want the hard work of producers and roasters to come through.

We also use a two group Slayer Espresso machine.The thing about this machine is that you can’t pre-programme it. It gives us a lot of freedom, but we have to pay close attention to what we’re doing. Press a button and then waiting for the shot to end after a certain amount of time (like you do with volumetric machines) would end in a lot of mess.
So for us, scales are a must. We’ve been through just about every model on the market and have yet to find one that satisfies us – making this the perfect environment in which to test the Acaia Lunar.

acaia scale brew

Inconspicuous, functional, durable, and intuitive: the Acaia Lunar.

slayer coffee machine

Our beloved two group Slayer. Despite all the wonderful things it can do, it doesn’t have a digital display or gravimetric scales (not a common feature on any machine).

The Acaia Lunar’s Features

1. Calibration

Being the coffee nerd that I am, I was more excited than most to find that the Lunar comes with a true weight designed to calibrate the scale for use. Though many would argue that this isn’t necessary, for me it was an indication that Acaia is serious about what they’re doing. You can recalibrate every day if you want, depending on how serious YOU are.

2. Water Resistance

We’ve killed many scales over the last few years through water/heat exposure. Often, you can bring them back to life by drying them on top of your espresso machine’s tray… but it’s not a certainty.

The image below illustrates the Lunar’s resistance. It’s important to note that you need to allow the unit to cool and dry after this kind of exposure, but in the interest of testing its durability, I felt compelled to risk all.

Also, I really wanted to take this photo.

Acaia water resistance
acaia heat resistance

True weight for calibration and some serious water/heat resistance #baristaporn.

The Acaia Lunar in Action: Modes

Having confirmed that the Lunar is idiot (that’s me) proof, it was time to test its abilities.

The Lunar has various modes that allow for different levels of automation. We considered using the auto-tare/timer start mode, which would allow for a cup to be placed on the scales, the scales to measure the weight of the cup and treat it as zero, and then the timer to start. However, the timer stops at 15 seconds and then resets. As we run a long preinfusion of 30 seconds on the Slayer, it made this impossible. Had our preinfusion been shorter, however, this would have been a fun mode to use.

Instead, we made use of the droplet mode and the triangle and square mode. We need scales to monitor two variables: time and yield. Previously, we’d been using another set of scales in conjunction with a digital timer. It was… painful. Both of these modes, however, offered a way around this problem.

Droplet mode:

In this mode (indicated by a droplet icon on the right of the LED display), you place a cup on the scales and tare manually. Then when liquid hits the cup, the timer – and obviously the scale – will initiate.

So how did it do?

Once our pre-infusion cycle yields 6 grams in the cup (this usually occurs at around 30 seconds but will vary with different coffees) we ramp up to 9bar pressure and extract until it’s yielded our target. If all this is like reading a foreign language, to put it more simply, every coffee is different and each roaster has their own style. As of such, some coffees taste better as shorter extractions (less volume in the cup) and others as longer extractions (more volume in the cup). This means that there’s some variety in the yield and time for each coffee.

droplet method continued

Droplet mode in action.

The Lunar was remarkably responsive and the droplet mode allowed us to accurately monitor one variable: yield. However, it only allowed us to track half the the extraction time. Why does this matter? Will the world end if we don’t track the time completely? Yes, yes it will, don’t ever question me.

Just kidding!

Seriously though, the key to good coffee is consistency. We record all this information so that, if we set the parameters for a new coffee and there’s a different barista on the next day, they will know that it tasted best when extracted over x amount of time and yielding x amount of liquid. Without that information, re-creating that perfect coffee becomes just a matter of luck.

Triangle and Square:
On paper, this is exactly what we wanted. You put the cup on the scale, the scale tares and, as long as you kick in the pre-infusion cycle at the same point, you’ll be able to monitor the entire extraction for time and yield.

triangle and square method

The triangle and square mode. On paper, it’s perfect.

The problem is that you need to be 100% focussed on the Acaia Lunar so that you know when to start the pre-infusion cycle.

I’m certain there are cafes for which this mode will work perfectly – but as a small cafe with minimal staff, it proved less than ideal. As much as we may want it to be all about the coffee, we can’t forget service. Even if we’re focussed on pulling a bangin’ EK43 Slayer shot that has the potential to change someone’s life (hey, it could happen), the moment a customer enters our doors we have to look up, smile, and welcome them.

The Acaia Lunar in Action: Manual Use

So although the Acaia Lunar has 3 modes measuring time and yield to some degree, none of them suited our particular café and setup. This doesn’t mean they’re impractical; plenty of cafés may find these modes work well for them.

However, does it mean that if – like us – you work in a small café and use a long preinfusion, the Acaia Lunar is useless?

Actually, no.

We’ve been running the Lunar as a manual scale, starting the time as we initiate the extraction and cutting it off as we reach our target yield. You can see that the extraction has been pre-infusing for almost 30 seconds. Slayer recommends you aim for around 7 grams out in the cup before you ramp pressure up using the paddle. We’re following their lead and, in conjunction with the Lunar, we’re able to pull as much out of the coffee as possible – and, more importantly, repeat that with ease.

Of course, if the modes were better suited to our café and setup, we would be using them. They’re convenient and highly accurate. Yet even manually, these scales improve our extraction.

manually using acaia

Using the Acaia Lunar manually may, depending on your café and setup, be the best option.

The Verdict

Working in the specialty coffee industry is full of challenges. One of these is that sometimes we use equipment in ways it was never intended to be used: the EK43 is a bag grinder; Hario brew scales were never designed to weigh shots in/out; and filter roasts, by definition, aren’t intended for espresso.

Yet all of these things happen. (You know it’s true.)

So I see the Lunar as a product driven by a change in the third wave coffee industry. It fills a market niche perfectly: it’s fast, accurate, adaptable to different service conditions, and highly durable. I’ve dropped it multiple times and had near to boiling espresso run over it when I’ve got distracted – and still it kicks on.

Is it worth the price tag? If the “Sold Out” status of the Lunar is any indication of its popularity, the market seems to think so.

In conclusion: the Acaia Lunar is a high-quality product that fills a strong need. Far from being superfluous, it has the power to improve both your extraction and consistency. As new as it is, it’s become a tool I’d rather not do without.

Final Notes:

  • Though easily adapted for pouring filters, it’s smaller size compared to the pearl means batch brewing with something like the Chemex isn’t going to work.
  • This review should not be considered a full assessment of the Lunar’s abilities. We also used it to brew on location in Brazil, where its portability and micro USB charging made it ideal for filters on the go. Several operators have also been syncing it with phones and espresso machines.
acaia scale filter brew

The Acaia Lunar: reliable and versatile.

Have you tried the Acaia Lunar yet? Let us know how you find it in the comments, on Facebook, or on Instagram.

Edited by T. Newton.

Perfect Daily Grind.