In recent years air-pump-driven espresso machines have emerged. These machines use compressed air to force the hot water through the coffee grounds. The hot water is typically added from a kettle or a thermo flask. The compressed air comes from either a hand-pump, N2 or CO2 cartridges or an electric compressor. One of the advantages of the air-pump-driven machines is that they are much smaller and lighter than electric machines. They are often handheld and portable. The first air-pump-driven machine was the AeroPress, which was invented by Alan Adler, an American inventor, and introduced in 2005. Handpresso Wild, invented by Nielsen Innovation SARL, a French innovation house, was introduced in 2007.
That said, it’s not as elegant to use as the OXO machines. (Nor is it as nice to look at. One tester described its tall, bulbous body and squat carafe as “UFO-like.”) Take its eight-button controls, for example, which you use to toggle among brew modes, scroll up and down within the menu, and engage a manual brewing feature. Programming it to start brewing at a certain time was about as intuitive as setting an alarm on a clock radio — easy enough, but more technical than sleek. OXO definitely feels like the future; Behmor is more, “If it ain’t broke, why fix it?”
The built-in burr grinder is high quality, and you can easily adjust the grind size and amount with a dial on the front of the machine. You can choose to use either a single- or double-wall filter basket, and the grinder will automatically adjust to give you the right about of coffee grounds for your brew. Reviewers love that it comes with the grinder and praise its quality.
The very first espresso machines worked on a steam-pressure basis, and they’re still in use today. With this type of machine, steam or steam pressure is used to force water through the coffee grounds and produce espresso. Some steam-driven machines can produce a measure of foam “crema.” But they can’t generate enough pressure or provide the precise temperature control necessary to produce true espresso: They simply make a very strong cup of coffee. However, they cost considerably less than pump-driven machines. Our verdict is that if you’re a true espresso lover and seeking to make a good shot at home, we recommend you steer clear of steam-driven machines. They’ll likely disappoint you.
All of the espresso machines we tested only included a single boiler for heating. This means that there's only one mechanism for heating both the water for brewing and the steamer wand. Because of this, it'll take the steamer wand a while to heat up after pulling the espresso shot, since the steamer wand operates at a much higher temperature than the brewing temperature of around 195°F. It is possible to buy a home machine with a double boiler (Breville makes one) but this raises the price significantly (we didn't test the Breville because it's over $1,000), and the minor wait time wasn't a major concern for us. We figured it wouldn't be for home brewers either.
Our brew-performance tests measure the brew temperature and contact time (how long water stays within a sweet spot of 195° to 205° F for brewing). We measure concentration using a refractometer, a device that measures the amount of coffee dissolved in each brew. Our convenience tests look at how easy it is to set timers, fill the reservoir, clean the machine, and more. And for the first time, we’re incorporating predicted reliability and owner satisfaction ratings into the new Overall Score for each model. We determine these ratings for each drip coffee maker brand using survey data collected from thousands of CR members.