Some machines use a single boiler kept at steaming temperature, but water for brewing is passed through a heat exchanger, taking some heat from the steam without rising to the same temperature. Although the water for brewing remains at a lower range than that required for steaming milk, it is still too hot for proper coffee extraction without first cooling; thus this type of machine requires a cooling flush of 4–6 seconds prior to the first espresso pull. Once the machine is dialed into the proper temperature, as many shots can be pulled as required without refreshing. However, if the user leaves the machine idle again for some period, the flushing process will need to be repeated. The HX variety is found in many mid-range machines and many users install thermometers to assist them is dialing in correct temperatures. There is some controversy as to the temperature stability of the brewing water, since it is indirectly converted from steaming temperature to brewing temperature, rather than kept at a brewing temperature.
Manual or semi-automatic machines offer more control of shot quality. Because when to cut the shot (brew time) is a critical variable, which is often adjusted shot-by-shot, semi-automatic machines are often preferred over automatics, though some machines are automatic. Manual machines are more popular in Europe, where it is more common to drink straight espresso.
Tamp: To ensure the espresso is evenly packed, your machine comes with a tamp, which you’ll press into the basket against the grounds. This step is important: When you pull a shot, the water will go to the place of least resistance, avoiding densely packed areas. This denser espresso won’t be properly saturated, making it under-extracted and sour, while the looser espresso will be over-extracted and bitter.
If all you’re looking for is a gorgeous cup of coffee and no fuss, we strongly recommend the Bonavita BV1900TS. It’s the smallest machine among our top picks and, at $190, the cheapest. Even better, it ranked in the top three out of 10 during our taste tests. It’s also the simplest and most straightforward: one button you click to start brewing, and that’s it. You can’t program brew times; you can’t play around with water temperature; and it even lacks some convenient touches like a brew basket that attaches to the machine (when you’re done brewing, you have to place the brew basket on a plate or in the sink before it makes a total mess). But it’s by far the fastest machine out of our top picks, brewing up a full eight-cup pot in under six minutes. It’s a straightforward, high-end coffee maker that leaves little to complain about.
Some machines come with all the accessories you need to make espresso, but others don't. Check to see if your machine includes any accessories before you buy them. You will need a grinder to have freshly ground espresso, a milk frother or a milk frothing pitcher if you like foamy milk for cappuccinos or lattes, and a tamper to press down the coffee grounds before you make espresso. We explain why you need each one and recommend which ones to buy below:
With the Nespresso, you have a few options when it comes to brews: a single espresso, double espresso (2.7 ounces), a gran lungo (5 ounces), a regular 7.7-ounce coffee, or an alto coffee which is 14 ounces of caffeinated bliss. Nespresso models come with a complimentary gift, which means this machine comes with a 12 pack of various Nespresso capsules of all different flavors. And since this is a bundle deal, it also comes with the Aeroccino 3 milk frother.
The Bonavita Coffee Brewer performs stellar when it comes to coffee drip brewing, easily outpacing more expensive coffee makers. It'll take about six minutes to create 44 ounces of coffee. Brisk brewing has caught the attention of the Specialty Coffee Association of America, since it's threshold for recognition is a brewing time of fewer than eight minutes.
Espresso shots need to be pulled between 186 and 194 degrees F. If the water is too cold when it hits the espresso, the shot tastes sour. Too hot, and it tastes burnt. It’s trickier to hit this window if you also want your machine to steam milk, since steam requires a higher temperature — at least 212 degrees. But we struggled to get several of our machines just to pull decent espresso, never mind the milk. Sour shots were a clear sign that the water wasn’t hot enough; scorched shots indicated that the water climbed over 200 degrees.
For example, if your coffee tastes a bit salty or sour, the grounds are under-extracted, which can be remedied by a finer grind. But what if only some of your grounds are too coarse, and others are too fine – and maybe some are just right? Having uniform grind size throughout your brew basket makes it easier to isolate and adjust this variable in order to get the level of extraction you want. The only way to achieve that is with a burr grinder. Miller — as well as a handful of our other experts — recommends the Barazata Encore Coffee Grinder ($129).
A cafetiere (Coffee Plunger, French press in US English) requires coffee of a coarser grind than does a drip brew coffee filter, as finer grounds will seep through the press filter and into the coffee. Coffee is brewed by placing the coffee and water together, stirring it and leaving to brew for a few minutes, then pressing the plunger to trap the coffee grounds at the bottom of the beaker.
On August 27, 1930, Inez H. Pierce of Chicago, Illinois filed patent for the first vacuum coffee maker that truly automated the vacuum brewing process, while eliminating the need for a stove top burner or liquid fuels. An electrically heated stove was incorporated into the design of the vacuum brewer. Water was heated in a recessed well, which reduced wait times and forced the hottest water into the reaction chamber. Once the process was complete, a thermostat using bi-metallic expansion principles shut off heat to the unit at the appropriate time. Pierce's invention was the first truly "automatic" vacuum coffee brewer, and was later incorporated in the Farberware Coffee Robot.
Once you start brewing, it makes a really, really good pot of coffee. Our taste test revealed the OXO On 12-Cup coffee was “dark and strong” and appealed to the more traditionalist coffee palates. The great flavor comes from the brewing process. The OXO machines have wide shower heads with multiple ports through which water streams, dispersing it evenly throughout the brew basket. Lots of other coffee makers spout water through just one hole, or through shower heads with a smaller radius, which can increase the chances of uneven extraction.
CR’s take: Though this Bialetti lacks typical drip-machine features such as programming and brew-strength control, it more than compensates with a Very Good rating in our brew performance test and a crisp 8-minute brew time. If you’re the type who sometimes prefers a morning shot of espresso to a cup of joe, this twofer—drip machine beside espresso maker—may be for you. It features a built-in milk frother, a permanent coffee filter, and auto-shutoff. CR does not yet have enough survey data on Bialetti machines to rate them on reliability and satisfaction, but when we do, we’ll add that info to our ratings.