The Decent Espresso DE1 model is an espresso machine like none other. The small form factor belies the remarkable capabilities of this machine. Significant technological innovations include rapid temperature adjustment, brew pressure control, flow rate specification, real-time sensor feedback, and upgradeable software interface.

Decent Espresso markets a wide range of other espresso gear, with three espresso machine models currently in the lineup: DE1+, DE1PRO, and DE1XL (DE1CAFE model is planned for next year). The DE1PRO features heavier-duty components than the DE1+, but is otherwise very similar. Both espresso machines are geared towards home baristas. The DE1XL and the planned DE1CAFE are designed for commercial use.

This is a review of the DE1+, but I will refer to both the DE1+ and DE1PRO models simply as "DE1".


Decent Espresso DE1+ image and evaluation model courtesy Decent Espresso

Executive summary

Simply stated, the Decent Espresso DE1 is an espresso machine for the 21st century. After 6 months with the DE1, I'm hooked. The DE1 pulls great shots of espresso, offers unparalleled extraction control and feedback, and makes other espresso machines feel, well, primitive by comparison. Moreover, it's put a lot of the excitement and fun back into espresso for me. Highly recommended.

Features

Let's take a look at the most interesting features of the DE1:

• Small form factor: The DE1 is roughly one half the size and one third the weight of my 1-group Spaziale Vivaldi S1, making it ideal for small kitchens. It comes in a wheeled suitcase, and is highly portable. The machine can be drained and packed for transport in under five minutes.
• User interface: The DE1 is controlled entirely by Android tablet. There are no buttons or dials, other than an on-off switch at the rear of the machine. The tablet communicates with the machine via Bluetooth, and controls it with a software app. Advantages of this should be immediately apparent:
  • software updates can be "pushed" immediately via the Web
  • multiple interfaces can be selected, ranging from simple 3-button GUIs to advanced extraction profile editors
  • enterprising members of the community can contribute to the app software
• Temperature control: The DE1 heats water on the fly for brewing, milk steaming, and hot water dispensing, using thermocoil technology. A mixing manifold combines room temperature water with heated water to provide the desired temperature. There are several advantages to this approach: excellent temperature stability, temperature monitoring at the puck as well as the "boiler", near-instantaneous brew temperature changes, even automatic temperature compensation for cold coffee grinds at the beginning of the shot. From a cold start, the machine is ready to brew espresso in only four minutes.
• Sensor feedback:The DE1 provides temperature, pressure, flow rate and extraction weight in real time, throughout the extraction. This information is presented graphically as the shot progresses. Extraction data for every shot are stored on the tablet for later analysis.
• Extraction profiling: The DE1 allows you to specify temperature, pressure, and flow rate throughout the extraction. Different steps in the extraction may have different temperatures, pressures, and flow rates. These profile steps are specified using a profile editor. At present, no other home espresso machine offers this capability.

Decent Espresso hosts a private online community ("Decent Diaspora"), whose members include staff and DE1 owners. This community is comprised of exceptionally active and helpful individuals. It is a great asset to those starting out with the DE1, looking for solutions to problems, sharing discoveries, suggesting improvements, and distributing software.

The DE1's combination of extraction control and sensor feedback provides an unparalleled opportunity for learning about espresso. For the scientifically inclined, the DE1 is a precision tool for experimentation and testing theories about espresso.

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Bench threads are kept closed, so once the review is done, it's easy to read. There's a separate thread in the Bench forum (Comments on Decent Espresso DE1+ Review) for users to post questions and provide review feedback.

Performance

Espresso
Ah, but how does it taste? The DE1 produces espresso with excellent flavor and clarity, allowing you to fully experience what the coffee bean has to offer. Once dialed in, extractions are both consistent and forgiving. I have extracted a wide variety of coffees on the DE1, ranging from lighter roasts (Dragonfly Leam Hammer) to classic medium-dark Italianate blends, as well as SO Guatemalans and Ethiopians. All yielded enjoyable results.

They say a picture is worth a thousand words:


And a video should be worth a thousand pictures: The DE1 gives you the ability to tweak temperature, pressure and flow in ways that no other home espresso machine can match. This increases your options, so be prepared to grind through a lot of coffee! This is not necessarily a bad thing. Espresso lapsed into a humdrum routine for me years ago. The DE1 has put back much of the exploration and fun into making espresso. There are many things to try, and every one provides a rich learning experience.

For this review, I primarily compared DE1 extractions to those on a very different machine, the Spaziale Vivaldi S1. The S1 is a single group, fully plumbed, rotary pump, commercial espresso machine without preinfusion. It has a 53mm group head and non-precision baskets, in contrast to the standard 58mm group head and precision baskets of the DE1. DE1 and S1 extractions are notably different. DE1 shots feature cleaner taste, greater clarity, and improved flavor separation, whereas body/mouthfeel is noticeably enhanced on the Spaziale. With lighter roasts, where a long preinfusion is practically essential, the DE1 produced obviously superior extractions.

Despite extensive experimentation, I was unable to match S1 body/mouthfeel on the DE1. To be fair, I had a similar experience when I reviewed the Breville Dual Boiler BES920XL. ("BDB extractions showed slightly more sweetness, clarity, and separation of flavors than the S1 pours. The S1 extractions were thicker and richer with better mouthfeel.") This may be due to grouphead size and geometry, the higher water debit of the S1 rotary pump, non-precision 53mm S1 baskets, greater head space above the DE1 puck, or other factors. Similarly, I cannot match the sweetness, clarity, and flavor separation of the DE1 on the S1. One machine is not better than the other, but they are distinctly different.

In his landmark book Everything But Espresso, Scott Rao suggests that for brewed coffee, flavor clarity and body are inversely related. This observation could hold true for espresso as well. These two machines (DE1 and S1) may represent opposite ends of the extraction spectrum, with the S1 at the "press pot" end and the DE1 at the "Chemex" end.

Steaming milk
Like many espresso aficionados, I enjoy cappuccinos. The DE1 is a decent espresso machine for lower-volume milk drinks. Steaming 90-100ml milk for cappuccinos takes less than 20 seconds on the DE1, starting with whole milk from the refrigerator, and steaming by "touch" to microfoam. DE1 steam is exceptionally dry, and incorporates only half the water weight of the S1 for a given volume of milk. Although you cannot steam and pull a shot simultaneously, there is no wait time between brewing and steaming (you can begin steaming immediately after extraction).

"Big gulp" latte lovers may find that steaming large quantities of milk is slow. Milk steaming time is proportional to the quantity of milk, so 15s for 3oz scales up to 60s for 12oz. Fortunately, the DE1 allows automatically timed steaming, and the no-burn steam wand can be positioned in the milk pitcher for hands-free steaming. For example, you can set steaming time for 6oz to 30s, position the steam wand for hands-free steaming, and let 'er rip. At the end of steaming, short puffs of steam continue until you hit stop, ensuring that microfoam does not separate and milk does not get sucked back into the steam wand.

"Ghost" steaming on the DE1

Another fun feature: the DE1 plots temperature, pressure, and flow rate during steaming. This is a useful diagnostic: erratic oscillations in pressure or flow are indications that it's time to clean and/or descale the wand.

Unpacking

The DE1 ships in a wheeled suitcase:


The contents are secured with tailored foam inserts:


This suitcase makes the DE1 highly portable. It took me less than five minutes to drain the machine and return it to the suitcase for transport to a friend's house.

Classic DE1 observation positions

Time to transport the Spaziale Vivaldi S1: infinite (I wouldn't even consider it).

Setup

Setting up the DE1 is simple, and takes just a few minutes. Place the machine on the counter, screw in a handle, slide in the water reservoir, add the drip tray, and plug in the power cable. If you want to position the Android tablet on top of the machine, then attach the tablet stand and plug in the USB cable for charging. That's pretty much it.


unpacked ...


... and assembled

Once again I will point out the small size and light weight of the DE1. By comparison, my Spaziale Vivaldi S1 is 15H x 16.5W x 16.5D, and weighs 65 pounds.

Tale of the tape: DE1 is one-half the width and one-third the weight of my Spaziale Vivaldi S1

The DE1 features a ceramic water reservoir with a capacity of just under 2 liters. Kits are available for fully plumbing the machine. The drip tray is also made of ceramic. The app continuously displays water level, and an "out of water" graphic appears when the water level gets low. To refill the reservoir, remove the drip tray, push up a water lever in back of the machine, and slide out the reservoir a few inches.

Sidebar: espresso extraction

This is a review of the espresso extraction process, which provides useful background for extraction profiling.

Espresso is a coffee brewing method, in which finely ground coffee is extracted for a short period of time, with hot water under high pressure (traditionally 9 bar). The initial extraction phase is (misleadingly) called preinfusion. In this phase, water flows into the puck and saturates the grinds. The dry puck offers little resistance to flow, and pressure is close to zero. As the puck saturates, the coffee grounds swell, resistance increases, pressure builds, and flow slows. At this point, drops of espresso begin to appear at the bottom of the basket. The end of preinfusion is a fuzzy concept, but I prefer to define it as full puck saturation or "water in = water out": when flow into the basket is equal to flow out of the basket.

Some machines provide a "low pressure" preinfusion step (e.g., 3 bar), but this refers to pressure at the pump, not the puck. Pump pressure is only indirectly related to flow rate. The rotary pump on my Spaziale, for example, has a significantly higher water debit (flow rate) than a vibration pump, and saturates the puck faster, regardless of pump pressure. During preinfusion, puck pressure is close to zero, and so it makes more sense to specify preinfusion in terms of flow rate. For example, a puck should saturate twice as fast at 8ml/s as 4ml/s.

After preinfusion, standard non-profiling pump machines generate full brew pressure (~9 bar) until the shot ends. Flow rate often increases towards the end of the shot, as the puck erodes (coffee compounds wash out of the puck, into the cup). Profiling machines, however, allow you to adjust pump pressure as the shot progresses. A declining pressure profile helps to maintain a steady flow rate throughout the extraction, which may improve the shot. This was initially observed in spring lever machines, where unwinding the spring generates less pressure on the puck towards the end of the shot. Pump-driven pressure profiling machines (such as the Lelit Bianca) have recently become available for the home barista. These machines typically provide a "paddle" that allows the user to adjust brew pressure during the extraction.

Extraction profiling on the DE1

Extraction profiling on the DE1 is quite different from pressure profiling on a machine like the Lelit Bianca. The extraction profile must be specified before the shot. Once extraction begins, the user can only intervene to prematurely terminate the shot. Control over the extraction profile is highly accurate and reproducible. The user can specify temperature, pressure, and flow rate throughout the extraction. The shot may be terminated based on time or, with a Bluetooth scale, by weight ("gravimetric" extraction). No more guessing at brew ratios!

There are several methods for specifying an extraction profile on the DE1. First, you may select one of many preset profiles:


Second, you may specify (and save) your own simple pressure or flow profile. As the names imply, a pressure profile specifies the desired puck pressure, and a flow profile specifies the desired flow rate. Finally, you may dive into the advanced profile editor, mixing and matching pressure, flow, and brew temperature throughout the extraction.

Let's start with simple pressure profiling. There are three phases: preinfusion, hold, and decline. These correspond closely to the extraction phases outlined in the sidebar on espresso extraction. Preinfusion is specified by flow rate, and terminated by time or pressure. Hold specifies a constant pressure for a given time. Decline gradually reduces the pressure to a lower pressure over a period of time. For example, the user might specify preinfusion at 6ml/s to 6 bar pressure (or 20s), then rise and hold to 9 bar for 5s, followed by a decline to 4 bar over 35s.

With a Bluetooth scale (such as the Skale), you can terminate the shot at a desired extraction weight rather than a prespecified time. To achieve a 1:2 brew ratio with a 17g dose, you would specify an extraction weight of 34g. The shot will end when the scale registers 34g or the decline phase reaches 35s, whichever comes first.

The DE1 profile editor allows you to create and store extraction profiles by clicking and dragging slider bars for each of these phases. Brew temperature is easily specified as well.


Extraction data is displayed in real time during the shot. Here is an extraction plot from a shot that used the above profile:

real-time extraction data for a 17g dose of Temple Dharma

Note the flow rate (blue curve) of 6ml/s during preinfusion, which ends when the pressure (green curve) rapidly ramps up at 10s. After 5s the pressure declines towards 4 bar, and the shot ends ~30s later when the espresso weight in the cup (brown curve) hits 34g. Sweet!

Simple flow profiling is similar to pressure profiling, but instead of specifying pressure, you specify flow rate. For example, a flow rate of 1ml/s should extract 30ml over 30s. However, flow profiling is trickier to master than pressure profiling, and I recommend that DE1 users start with simple pressure profiles.

As for any espresso machine, brew pressure and flow rate depend on correct dose and grind. For example, too fine a grind can "choke" an extraction. If you specify 1ml/s and the grind is too fine, you cannot achieve that flow rate, and pressure spikes. The converse is also true: too coarse a grind (or too low a dose) may prevent the puck from building enough resistance to achieve 9 bar pressure, and the shot will be a gusher.

Finally, the DE1 provides an advanced profile editor. This editor allows you to specify any number of extraction steps. Each step has its own time, temperature, and pressure or flow rate:


You can use the advanced profile editor for all sorts of stupid DE1 tricks. For example, Scott Rao has detailed a blooming espresso profile: after preinfusion, let the puck "bloom" for 30s (like brewed coffee), and only then ramp up the pressure. Others have created brewed coffee profiles that intersperse "pour" steps with "wait" steps. Decent Espresso is currently developing a basket, designed to work with the Hario V60 coffee dripper. This will disperse hot water in a spray pattern appropriate for a V60 extraction.

Extraction profiling is one of the DE1's most powerful features. Simple pressure profiles alone provide an enormous amount of control over the extraction. No other home machine offers flow profiling, let alone a combination of pressure, flow, and temperature profiling.

DE1 as lab instrument

The DE1 not only provides unprecedented control over the extraction, it also generates real-time sensor feedback throughout the shot. Sensor data is collected from multiple temperature sensors, a pressure sensor, and a flow meter, and displayed graphically as the shot progresses. Data are also stored in "history" files on the tablet, and may be analyzed for experimental purposes.

DE1 water flow diagram, showing heaters, pumps, mixing manifolds, and sensors

For example, in Illy's classic book Espresso Coffee: The Science of Quality, Petracco suggested that increased brew pressure does not necessarily increase flow rate (Ch.7 Percolation). Over a decade ago, Andy Schecter built a custom pressure profiling machine, and examined the relationship between brew pressure and flow rate. He found that flow rate increased up to 7-8 bar and then began to decline (results here).

At John Buckman's suggestion, I repeated these experiments on the DE1. Here are my results:

Shot weight (and thus flow rate) for an extraction peaks at 8 bar

This exercise illustrates two things:
1. The DE1 can be used, right out of the box, as a lab instrument for quantitative espresso experimentation.
2. Andy Schecter is at least a decade ahead of the rest of us.

Conclusion

The Decent Espresso DE1 is a remarkably innovative espresso machine that combines many unique features: small form factor, excellent ergonomics, short warmup time, rapid temperature adjustment, pressure and flow profiling, real-time feedback, and more. But it's not for everyone.

Those who desire manual control over the shot (via a lever or paddle) will not be happy with the DE1. Although the DE1 provides extraordinary control over the extraction, it must be specified ahead of time. Like most pump machines, once the extraction begins, it will run to completion unless terminated early.

This is brand-new technology from a small company, and you must have an early-adopter mentality to fully appreciate it. The hardware has not changed much since version 1.0 began shipping in April 2018, but software updates are still fairly frequent. This is both good and bad: updates bring new, improved features, but you must adapt to these changes. Documentation is spotty, and your best resource is often the online Decent Diaspora community.

As noted, the DE1 does an excellent job of producing microfoam, but steaming performance is slow for large quantities of milk. The DE1 cannot simultaneously pull a shot and steam milk, which is a requirement in commercial settings (the DE1CAFE model should be able to do this). For big gulp latte fans, an espresso machine with a large steam boiler may be a better choice.

Most others will find the DE1 to be an exciting new development in home espresso. It offers unprecedented manipulation of extraction parameters, useful real-time feedback, a great online community for sharing recipes and solving problems, and an excellent tool for learning and exploring espresso. With the DE1's kitchen-friendly style and choice of simplified user interfaces, even your significant other can be happy with this espresso machine.


Disclaimer

I have no financial interest in Decent Espresso. However, in 2016 I wrote basket analysis software used by Decent Espresso, and the DE1+ v.1.0 used in this review was generously supplied by Decent Espresso.