Mx Cool Aries: Big Burrs, Bold Brews

The MX Cool Aries is a fascinating new single-dose grinder hailing from Taiwan.

With its big conical burrs, magnetic design, and big conical burrs, it’s hard not to draw comparisons to other new Taiwanese brands such as Femobook.

But does the Aries have what it takes to stand out in an increasingly crowded market? Let’s take a closer look.

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About the brand

MX Cool is a relative newcomer to the coffee grinder scene, born from a successful crowdfunding campaign in Taiwan. The brand also makes a nifty little scale called “Katze”.

Despite their recent entry, they’ve quickly gained attention for their innovative designs and focus on single-dosing grinders. The Aries marks their first foray into the global market, and it’s clear they’re aiming to make a statement.

Design/Overview

At the heart of the Aries are its massive 83mm conical burrs – a similar size to the largest commercially available burr set – the Mazzer Robur.

This unconventional choice yields excellent results in the cup. The titanium-coated burrs feature a unique 12-pointed design, differing from the 10-pointed Mazzer burrs.

Here the 83 mm Aries cone burr is placed next to a regular hand grinder cone burr. The difference in size is striking!

Interestingly, the Aries’ outer burr rotates while the inner burr remains stationary, a design choice shared by few grinders like the Baratza Sette. I’m a huge fan of this design.

Both in theory and practice it offers some advantages over a more standard design with a burr chamber where an impeller pushes the grounds into the chute.

By removing these unnecessary steps the grinder will produce less clumps and retention. And any regrinding and heating of the grounds is also reduced.

If you think about it, manual grinders also work the same way. And they also tend to be better tasting across the board compared to electrical ones. Besides operating at a lower RPM, the other side of the equation is that the coffee falls directly from the burrs and into the dosing cup. So already here the Aries has a big advantage.

Created for single dosing

The MX Cool Aries is a single dose grinder, which means that it’s designed to grind only the amount of beans you need for each brew. This is different from traditional grinders with a hopper, where you fill it up with beans and then grind as needed.

Single dosing has become increasingly popular in recent years, especially among coffee geeks who want to have more control over their brewing process.

With the Aries, you weigh out the exact amount of beans you want to use for your shot or brew, and then you pour them into the grinder. The rubber fins inside the mini-hopper help to guide the beans into the burrs.

Single dosing has a few benefits:

First of all, your coffee will be fresher. When you store beans in the hopper of a grinder, they will start to lose flavor and aroma over time, even if you’re using high quality beans. You’re always grinding beans that have been sitting there for a while.
With the Aries, you can keep your beans in an airtight container, and then only grind what you need, when you need it.
Secondly, single dosing allows you to easily switch between different coffees. If you want to brew a fruity light roast in the morning and a chocolatey medium roast in the afternoon, it’s easy to do so. No need to empty the hopper and purge your grinder of the previous coffee.

Single-dose grinders are also designed to have lower retention/exchange. This is done by minimizing deadspace, or perhaps using a smaller or removable chute. You can make small adjustments to your dose, grind size, and brewing variables without wasting a lot of coffee, when there’s less retention. Interestingly, the Aries doesn’t have a chute in the traditional sense, instead the ground coffee falls directly down into the blind shaker, similar to how a manual grinder works.

Build Quality

Let’s talk about the build quality of the Aries. When you’re dropping over a grand on a grinder, you expect it to be built like a tank. Unfortunately, the Aries is a bit of a mixed bag in this department. The body is plastic, but it feels solid enough and has unique curves that are nice to look at. The base, dosing cup, and adjustment mechanism are all metal, giving it a premium touch.

And then there’s the plastic hopper. It just feels a bit out of place on a grinder of this caliber. It’s not a problem per se, but the lid feels a bit lightweight and flimsy.

The hopper and body is made of plastic and feel like they belong on a sub $1000 grinder.

Under the hood, things are looking pretty good. The burr carrier, adjustment mechanism, and dosing cup are all solid and well-made. The burrs themselves are titanium-coated, which should help with durability in the long run.

One thing I really appreciate is how easy it is to take apart for cleaning. The inner burr pops out with a simple twist, no tools required. And here’s the kicker – your grind setting stays put even when you remove the burr. That’s a nice touch.

Overall, the build quality of the Aries is good, but not better compared to midrange grinders like the Timemore 078 and DF 64 Gen 2. The plastic body and hopper might not be everyone’s cup of tea, but the important bits – the burrs, adjustment mechanism, and dosing cup – are all solid. I do think for the price you’re paying, that premium materials are warranted.

Using the grinder

The grind adjustment is stepless, but the lock button gives you a sense of security about the adjustment. You won’t accidentally change it.

The variable RPM control is a nice touch, letting you switch between 90-150 RPM.

Now, let’s talk about the elephant in the room – the grounds container. MX Cool calls it a “blind shaker,” even though there’s no lid included, so you can’t really do any shaking with it.

The grounds bin attaches to the grinder with magnets. It’s a cool and innovative concept overall, but the execution could use some work.

The lip of the rod is too shallow, so it’s prone to tipping over ever so slightly, which can easily create a mess. Dosing directly into a portafilter can be a bit of a hassle, too, since the catch cup will leave a ring along the edge of the grounds in the portafilter when you lift it. I prefer my dosing funnels to rest on edge of the portafilter – that way you can WDT with the funnel in place. If you have an indentation in the grounds, then you need to redistribute them again before you tamp.

Retention is pretty minimal as long as you’re using RDT (Ross Droplet Technique) AND using the little knocker on the side. We’re talking 0.1-0.2g for filter and espresso. This is the advantage of the burr design of the Aries – there aren’t a lot of nooks and crannies where grounds can get stuck.

However, I would still recommend using RDT because static will happen otherwise.

Taste and Performance

This is where the Aries really shines, especially for espresso. Those big conical burrs produce shots with a unique fluffy mouthfeel that you don’t get with flat burr grinders. It’s big and bold, but the clarity is still there, with flavors that linger long after you’ve finished your sip. I often don’t find conicals to deliver shots that take you on a journey that’s pleasant from beginning to end, but that’s the case here.

Playing with the RPM settings is a trip, too. For filter, I found the lower end around 90 RPM to be the sweet spot for clarity and forgiveness. Essentially, this is the same speed a hand grinder would operate at.

With espresso, lower RPMs give you more defined acidity, while higher RPMs produce a rounder, sweeter cup with that velvety mouthfeel I mentioned earlier.

Pour Over Coffee Flavor

Despite the MX Cool Aries being primarily an espresso grinder, it still performs admirably for pour over coffee. In my experience, the Aries produces a well-rounded cup with a pleasant balance of flavors.

When using it for pour overs, I found that the grinder accentuates the sweetness and body of the coffee. The flavors come through cleanly, with a notable depth that is sometimes lacking in other grinders. This is partly due to the large conical burrs operating at a low RPM, which generates less heat and ensures a more uniform grind size.

However, if you’re a fan of lighter roasts, you might notice that the clarity and acidity are not as pronounced as they would be with a high-end flat burr grinder. The Aries tends to highlight the sweetness and round off the edges, giving a smooth and enjoyable cup but potentially missing some of the vibrant, bright notes that light roast aficionados crave.

Challenges with Light Roasts and Precision Baskets

In my testing, I’ve found that the MX Cool Aries faces some challenges when grinding for lighter roasted coffees, especially when using a 58mm portafilter with a precision basket. If you like your espresso light and bright, you might notice that even at the finest grind setting, the flow through the portafilter can be faster than expected.

Here’s why: the lighter the coffee, the finer you have to grind it. Similarly, the larger the diameter of the portafilter and the more holes you have in the basket, the finer the grind needs to be. Modern precision baskets tend to have holes that extend further to the sides, which compounds the need for a finer grind.

With the Aries, this can lead to a situation where, if you’re pushing the grinder with these lighter roasts, your espresso machine might struggle to reach the desired 9 bars of pressure. Instead, it might only hit 3 or 4 bars, resulting in a “turbo shot”.

This is definitely something to keep in mind if you’re planning to use the Aries exclusively for lighter espresso. While it excels in many areas, those who prefer lighter roasts and use precision baskets might need to tweak their approach or consider this limitation.

And I think the Aries grinder could actually be fixed in a future version because I find that I don’t really need to go coarser than, let’s say, setting 6 or 7, if I am doing a pour over or French press. So, actually, there’s about half of the grind adjustment dial that I don’t use. If they change the threading or calibration system, then you would probably be able to go even finer, and then you would have your coarser settings further towards the coarser side of the adjustment dial.

Additionally, the espresso grinding range is a bit limited. Espresso grinding starts around 2, and I often grind all the way towards 0. With such a small space and a stepless grinder, it can feel challenging to find your way back to old settings. Without click feedback to indicate specific increments, like 1.2 or 1.4, it’s hard to know the exact difference between settings. This makes the espresso grinding range feel limited and adds to the need for a potential calibration system update.

Cleaning and Maintenance

One of the coolest things about the Aries is how easy it is to clean. The inner burr pops out with a quick twist, and you’re done. No tools, no fuss. Even cooler? Your grind setting stays put when you remove the burr.

The only tricky part is getting into the upper burr chamber for a deep clean, but that’s not something you’ll need to do every day.

It only takes a couple of seconds to release the cone burr of the Aries, making cleaning super easy.

Room for Improvement

As much as I dig the Aries, there are a few things that could be better:

Dosing cup:

The blind shaker dosing cup needs a redesign to prevent spills and make portafilter dosing easier. The lips of the dosing cup extend too far down into the portafilter, creating a ridge around the edge of the coffee. This means you have redistribute the grounds, and then you’ll probably need another funnel. If you need another funnel then what’s the point of the blind shaker?

Now it’s become sort of “trendy” to distribute grounds via blind shaking, it would make sense to include a lid for the shaker, so people have the option.
The texture inside the catch cup can make it difficult for grounds to slide out easily, and fines can build up over time.
The shallow bottom of the bell/rod can cause it to tip over easily, potentially letting grounds fall out. Espresso grounds are messy so this isn’t cool!
An alternative standard dosing cup option would be nice. Not everyone is a fan of the blind shaker design.

The blind shaker dosing cup, while a good idea, can be frustrating at times.

Build quality & general user experience

The plastic hopper could be a bit more premium and match the price better.
Light roasts might make the grinder stall occasionally.
Can’t grind fine enough for certain scenarios – for example very light beans in a 58 mm precision basket. Finer grind adjustment steps would give even more control.

The Verdict

The MX Cool Aries is a bold first attempt from a young company that’s not afraid to shake things up. Those giant 83mm conical burrs with their wild 12-pointed design, the easy cleaning, and the impressive cup quality across brew methods make it a compelling option for adventurous coffee geeks.

Sure, it’s got some quirks and a few areas that could be polished, but when it comes to the cup, the Aries delivers. It’s forgiving, produces a unique fluffy mouthfeel, and leaves you with sweet, lingering flavors.

At $1,300 to $1,400, it’s not a budget option by any means, and it’s going head-to-head with some stiff competition from other semi-pro machines such as the Mazzer Philos, the Lagom P64, and DF83V. But if you’re willing to roll with its idiosyncrasies and put flavor first, the Aries might just be the unconventional single dose conical grinder, you’ve been looking for.

If you’re itching to try something different and expand your espresso horizons, give the MX Cool Aries a closer look. It might just be the wild card your coffee setup needs.