Ascaso Steel Duo vs Diletta Mio

In my review of the Diletta Mio, it didn’t take people long to start noticing the similarities between it and the very popular Ascaso Steel Duo PID. So now that I have both machines in the lab, I thought I would do a comprehensive comparison to help you decide which is going be best for you.

There is a large enough price gap between the Steel Duo and the Mio that it’s at least worth mentioning, and that’s sort of what makes this comparison interesting.

Build Quality / Design

Starting off with the build quality, when you compare machines at slightly different price points, you would expect to also get a slightly different quality of materials and finishing. And in this case, that is exactly what you get.

The Diletta Mio is somewhat reserved in terms of its external finishing. The designers were clearly trying to fit as much functional value into the machine as possible, while keeping the price point down. This ABSOLUTELY is not to say that the Diletta is poorly built, quite the opposite. The shell is all metal, it comes with a great portafilter, the buttons are high quality and very tactile, and there’s zero plastic to be found in the build. However, certain areas such as the drip tray are pretty bare bones.

In comparison, the Ascaso is a noticeable step up. It also comes with a great portafilter, but the handle is now made of wood, as is the variable steam knob. The grouphead is beautifully sculpted, and just looks high-end, the cup rail has nice details… and the whole working area is illuminated, which is a really nice touch.

Apart from the bump in build quality, and I do recognize that aesthetics are subjective, but I find it hard to imagine that many people would argue the fact that the Steel Duo is the better looking of the two machines. I do wish that I had the Mio in black as well to make this a bit more apples to apples comparison, but either way, the Steel Duo just has a certain special sauce.

Both the Mio and Steel Duo are offered in black, white or plain metal finishes at no extra cost.

User Experience

Moving on to the experience of using these machines day-to-day, the Diletta has followed in the footsteps of the Ascaso in many ways, and that’s a good thing.

Both machines have one of my favourite features, which is a side-access water tank. These are much easier to access and fill in a home setting where espresso setups are often under overhead cabinets.

Both machines are also capable of brewing and steaming simultaneously, but neither are technically “dual boilers”. They both use a separate thermocoil to handle the steaming side, while the brewing is handled by another thermocoil in the case of the Steel Duo, and a 400mL brass boiler in the case of the Mio.

These quasi-dual boiler configurations are something that I really hope starts to pick up steam in the home espresso market, because they make total sense. This configuration is much more energy efficient when compared to something like a true dual boiler, but still offers plenty of steaming performance and capacity for home use, which we’ll get into a little later on.

The other benefit of both machines is that if you’re not steaming, you can choose to simply not heat up the steaming circuit at all. On the Mio, this is as easy as flipping a switch on the side of the machine. While on the Steel Duo, you’ll need to go into the menu system which I think makes it a little less likely that people will take advantage of the feature, which is a shame.

On the topic of energy savings, both machines also offer the option to set a sleep timer where the machine will automatically go into a low power mode after the selected amount of time.

In terms of start-up speed, because the Steel Duo also uses a thermocoil for brewing, it will get itself warmed up about 3 minutes faster than the Diletta, which has to heat up the whole 400mL boiler. Once up to temperature, both machines are equipped with PID temperature control, and the displays convert into shot timers while the shot is running.

The last big difference is that the Ascaso has a great dedicated hot water spout which is very useful if you plan on drinking Americanos, or even if you just have someone else in the house who drinks tea or other warm beverages.

Espresso Quality

Moving on to espresso performance, these are both excellent steps up from more entry-level machines such as a Breville or Delonghi, assuming of course that you pair them with a good quality grinder.

Having PID controlled temperature, and commercial 58mm sized portafilters is a big advantage over other lower priced options, and it leads to both the Mio and Steel Duo being able to produce very consistent and excellent quality espresso.

Both machines also have easy access to adjust the OPV if you feel the urge to play around with brewing at higher or lower brewing pressures from the stock 9 bar.

With that being said, the Ascaso Steel Duo does have a couple advantages over the less expensive Mio. The biggest one being pre-infusion. The Steel Duo allows you to program in pre-infusions of up to 5 seconds, and then you can also program in a pause after the pre-infusion for even further saturation if you want.

The other advantage comes by way of programmability. On the Ascaso, you can run shots completely manually, or program in two set shot volumes which are then easily triggered by toggling up, or toggling down the brewing switch.

Shot control on the Diletta Mio is all manual with one button to start and stop the shots. So you’ll need to pay attention to stop the shot at your desired yield every time.

One small aspect of the Mio that I actually prefer is the temperature display. It is always giving you a live readout of the true boiler temperature, even small fluctuations of a couple degrees. Whereas the display on the Ascaso appears to only show the set temperature once the machine has fully warmed up.

Of course, all of these features are for nothing if you don’t put in good quality coffee. A cheap machine with great coffee with always outperform an expensive machine with stale grocery store beans. For that reason, I’ll be leaving some excellent coffee linked HERE. Before you splurge on a new machine, upgrade your beans!

Steaming Performance

Considering these two machines have very similar steaming configurations, it shouldn’t be too surprising to learn that the steaming performance is also quite competitive.

Both machines come with no-burn steam arms to avoid stuck on milk, and both also come with single hole steam tips. The Mio also comes with a second 2-hole tip, which is a nice touch in case you prefer one style over the other.

In terms of speed, the Steel Duo takes around 45 seconds to steam a drink, whereas the Mio takes slightly longer at 55 seconds when using the same single hole steam tip. If you install the 2-hole tip, it brings the Mio down to around 50 seconds. Regardless, it’s a pretty clear conclusion that the Mio is around 10 seconds slower overall. Not a big deal for home use, but definitely worth noting.

The updated Steel Duo also now gives you the option to control the steam temperature, although I’m not sure I’d ever change it from the maximum, and it also adds a nice to use variable wooden knob compared to the Mio’s simple push button.


So, with all that being said, which one of these machines should you be going for?

If you are on a strict budget, you should feel absolutely no hesitation going for the Diletta Mio. It takes HEAVY inspiration from the form factor, features, and function of the Steel Duo, and offers you 90% of the performance, but at a lower price point.

However, if you aren’t tight on cash and simply want the better machine, then the Ascaso Steel Duo PID does justify its higher price tag. The finishes are more premium, the looks are stunning, it includes pre-infusion adjustment, a hot water spout, and more steaming power and control.

I think that these two machines very nicely compliment one another with their respective feature-sets and price points. You really can’t go wrong with either.

Need more? Watch the video!

Products Mentioned

Ascaso Steel Duo PID Review
Diletta Mio Review