Ascaso Steel Duo: An Espresso Machine That Breaks The Mold
Anyone serious about espresso-based drinks knows the importance of being able to steam milk and pull a shot simultaneously. The common way to tackle this problem is with a dual boiler or heat exchanger espresso machine, but both have serious downsides. They’re big, expensive, take forever to heat up, and are challenging to use and maintain.
Luckily, there is another way! The Ascaso Steel Duo espresso machine sidesteps all those issues while allowing simultaneous steaming and brewing. Keep reading this Ascaso Duo review to learn how – and much more.
Summary Box: The Ascaso Steel Duo
- Prosumer espresso machine with dual thermoblocks
- Improved volumetric controls and programmable pre-infusion
- Exceptional stainless steel build quality
This machine rocks! The fast heat-up time combined with the temperature accuracy make the workflow with this a breeze.– Lucas Felman, Customer
The Full Ascaso Steel Duo Review
Ascaso was founded in Barcelona, Spain, and has over 60 years of acclaimed coffee machine manufacture. But it has only recently gained widespread recognition in North America (1). The brand is known for making professional-grade machines that are easy to use and sport a cool vintage industrial look.
Brewing Capability – 4/5
The Ascaso Steel Duo programmable espresso machine allows you to pull a shot of espresso and steam milk at the same time, but it is neither a dual boiler nor a heat exchanger espresso machine.
What’s its secret? It uses dual thermoblock boilers – one thermoblock dedicated to brew water and one steam thermoblock.
Thermoblock Pros and Cons
Thermoblocks are uncommon in higher-end prosumer espresso machines, but they offer some significant advantages. A thermoblock heater is less expensive, more compact, and uses less energy. It heats up much faster. Every shot uses fresh water pulled straight from the reservoir and heated to temperature – meaning fresher taste and less risk of limescale build-up.
The downsides? For one, boilers generally have better temperature stability. They are also better for steaming milk with more steam power, which we’ll discuss in the Milk Frothing section below. You’ll also need a NEMA 5-20 amp plug and circuit to power this model, but an adaptor is included.
Temperature Control Is Crucial
The stainless steel thermoblock circuits in the Ascaso Steel Duo espresso machine have independent PID temperature control, which means enhanced stability versus lower-cost thermoblock designs. In our tests, the brew temperature fluctuated less than 1 degree Fahrenheit during extraction. As any espresso expert will tell you, temperature accuracy and precision are key factors in achieving the best espresso (2).
Many of the soluble compounds that we enjoy tasting in espresso will extract at the right concentration within a small temperature range.
Brew and steam temperatures can be adjusted independently in one-degree increments using the digital PID display on the front of the machine.
My favorite pro-level feature on this impressive machine is the programmable pre-infusion. It virtually guarantees consistently good-quality espresso, even if you haven’t mastered perfect puck prep (3). The Ascaso Steel Duo PID includes a commercial-standard 58 mm diameter portafilter, making buying accessories like a tamper, leveler, or puck screen easy The adjustable over-pressure valve makes it easy to tweak brew pressure, which you can monitor with the analog pressure gauge.
User Friendliness – 4/5
Ease of use is where this coffee machine shines, especially compared to a traditional dual boiler. Turn it on, and it is ready to brew in under 5 minutes – rather than the 30-plus minutes it takes to achieve temperature stability with a boiler.
This programmable espresso machine has enhanced volumetric controls. The volumetric programmable settings allow you to pre-program a designated volume for a single shot or double shot – plus a low-pressure pre-infusion stage. Pulling a delicious espresso shot is as easy as flicking a switch.
You can pull an espresso shot manually if you prefer to be more hands-on. The PID temperature control display doubles as a shot timer, and you can hone your skills by monitoring the pressure gauge. Prefer to be less hands-on? This model is compatible with Easy Serve Espresso pods.
Milk Frothing – 3/5
The milk frothing on the Ascaso Steel Duo PID is perfectly adequate for most users, but I won’t claim that it can match the steam power or quality of a boiler. The steam will be slightly wetter, and achieving the milk texture you want takes a bit longer. However, with practice, I prepared beautiful silky microfoam for latte art with dairy and oat milk.
An advantage of the thermoblock is that it guarantees continuous unlimited steam at constant pressure using minimal energy consumption. This comes in handy when brewing lattes for a crowd.
The Steel Duo features electronic steam control and a double-wall no-burn steam wand design. As long as you keep your hands away from the tip, you don’t risk a scalding.
Build Quality – 4/5
The build quality of Ascaso espresso machines is top-notch. Each one is hand built in Barcelona, Spain, using high-quality materials.
The Ascaso Steel Duo PID body is a durable stainless steel casing, as you might guess from its name. It’s available in either black or white powder-coated carbon steel or classic polished stainless steel. I don’t usually put a lot of weight on aesthetics, but I’d be remiss not to mention the beauty of the Steel Duo.
It has a sleek, modern design, almost Scandinavian in style. And the portafilter has a beautiful red walnut wood handle at no extra cost.
Thanks to the thermoblock design, this programmable espresso machine is compact, measuring 10.5” wide by 12.5” deep by 15” tall. Unlike a typical dual boiler, you won’t have to dedicate an entire kitchen corner to house it.
Ascaso is confident enough in the build to offer a generous warranty. The machine and workmanship are guaranteed for one year, and the boilers are under warranty for five years for domestic use.
Cleaning and Maintenance – 4/5
The cleaning and maintenance needs of the Ascaso Steel Duo espresso machine are much simpler than a traditional semi-professional coffee machine.
With no boilers, you don’t need to worry nearly as much about the limescale build-up. In traditional espresso makers, hot water sits in the boiler, providing ample opportunity for scale deposits. With the thermoblock, there is never any stagnant water in the machine. Of course, we still recommend using filtered water, if only for the cleaner-tasting coffee.
Another big difference between the Steel Duo and a standard dual boiler is that it has a programmable automatic cleaning mode. More often seen on super-automatic espresso machines, automated cleaning is a huge timesaver.
All you need to do regularly is top up the 60-ounce water reservoir and empty the drip tray. Because this machine uses a vibratory pump, it’s incompatible with direct plumbing.
Things We Liked:
- Can brew and steam simultaneously
- Programmable shot volumes and pre-infusion
- Excellent temperature stability with PID
- Durable stainless steel build
Things We Didn’t Like:
- Low steam pressure
- Steam from a thermoblock is wetter than a boiler
- Water reservoir is relatively small
Don’t Buy The Ascaso Steel Duo If…
- You don’t make a lot of milky drinks: If you’re more likely to enjoy an espresso or Americano than a latte or cappuccino, don’t waste money on a machine that can brew and steam at the same time. Many of the best home espresso machines we recommend will meet your needs at a much lower price. There is also a version of the Steel Duo with a single thermoblock, the Ascaso Steel Uno.
- You want something with more programmability: If you like the fast heat-up time of the Steel Duo but want more programming options, consider the Decent DE1. It’s one of few machines on the market that can match the heat-up speed of the Steel Duo, but it runs with complex software that lets you get as nerdy – or as hands-off – as you want.
- You prefer a boiler to a thermoblock: If you prefer the dryer and more power steam you can only achieve with a steam boiler, you’ll be happy to hear there are a few on the market nearly as compact and affordable as the Steel Duo. Our favorite is the dual-boiler Lelit Elizabeth.
The Ascaso Steel Duo is a unique programmable espresso machine that uses two thermoblocks rather than dual boilers. While this limits it relative to a commercial machine, it has significant advantages for the average home user. It’s smaller, cheaper, faster to heat up, and easier to maintain than a more traditional design. And, most importantly, it still makes an incredible espresso shot or milky drinks. If you want the quality of a professional home espresso machine without the headaches, this is a fantastic option.
- Bryman, H. (2020, November 23). Ascaso Partners with Espresso Parts to Launch Ascaso-USA. Retrieved from https://dailycoffeenews.com/2020/11/23/ascaso-partners-with-espresso-parts-to-launch-ascaso-usa/
- Stanley, Z. (2022, June 20). How does temperature stability affect espresso extraction? Retrieved from https://perfectdailygrind.com/2022/06/how-does-temperature-stability-affect-espresso/
- Aloe, R.M. (2021, September 14). Pre-Infusion for Espresso. Retrieved from https://towardsdatascience.com/pre-infusion-for-espresso-dab5185b8094