The term dual boiler is used narrowly for machines with two separate boilers, and more broadly for what are more properly called dual heater (DH) machines,[citation needed] featuring a boiler for brewing and a separate thermoblock (TB) for heating brew water to steaming temperature – opposite to HX machines, where the boiler is at steaming temperature and is cooled to brewing temperature.
Dual-boiler espresso systems are undoubtedly the gold standard for home or commercial equipment: They allow the machine to maintain the optimum temperature for simultaneously brewing espresso coffee (195–205 degrees Fahrenheit) as well as for creating steam (closer to 250 degrees Fahrenheit), which means no waiting around, watching your crema disappear while you wait to steam milk. The Breville also has programmable options for softly pre-infusing the coffee, and has a control valve that monitors extraction pressure—two things most home machines don't feature. If espresso is your go-to coffee every day, this is the machine for you.
Above all, good espresso requires precision. If you’re looking for phenomenal tasting notes, flavor balance, and texture, there is simply no room for error in the machine, the beans, the user, or even the weather. And even if you’re not holding out for the best coffee on the planet, the margin for error is still slim. To test the machines, we pulled shots following the Italian Espresso National Institute's measurement guidelines and paid attention to the following markers of success:
A grouphead (or group head) is the receiver for the removable portafilter (or group handle). A typical consumer espresso machine normally has only one grouphead, while popular professional machines, such as those used at commercial coffee shops, can contain anywhere from one to seven. During the process of extracting a shot of espresso, hot water is forced through the grouphead under pressure. The grouphead contains many holes (the shower) that attempt to distribute the pressurised water evenly over the surface of the grinds in the portafilter basket and thereby achieve an even cross sectional flow.[3]
"My absolute love of the Delonghi Maginfica ESAM3300 is hard to describe. It has been a faithful crema steeped friend and morning ritual for at least 8 years, and the current unit I bought as a replacement last week (another ESAM3300) is a testament to why I give this well built Italian Stallion "super automatic" espresso dream machine a SOLID 5 star rating.
The first machine for making espresso was built and patented by Angelo Moriondo of Turin, Italy, who demonstrated a working example at the Turin General Exposition of 1884. He was granted patent no. 33/256 dated 16 May 1884 (according to the "Bollettino delle privative industriali del Regno d'Italia", 2nd Series, Volume 15, Year 1884, pages 635 – 655). A certificate of industrial title was awarded to Mr. Moriondo Angelo, of Turin, for an invention called "New steam machinery for the economic and instantaneous confection of coffee beverage, method 'A. Moriondo', Plate CXL".

There were lots of innovations from France in the late 18th century. With help from Jean-Baptiste de Belloy, the Archbishop of Paris, the idea that coffee should not be boiled gained acceptance. The first modern method for making coffee using a coffee filter—drip brewing—is more than 125 years old, and its design had changed little. The biggin, originating in France ca. 1780, was a two-level pot holding coffee in a cloth sock in an upper compartment into which water was poured, to drain through holes in the bottom of the compartment into the coffee pot below. Coffee was then dispensed from a spout on the side of the pot. The quality of the brewed coffee depended on the size of the grounds - too coarse and the coffee was weak; too fine and the water would not drip the filter. A major problem with this approach was that the taste of the cloth filter - whether cotton, burlap or an old sock - transferred to the taste of the coffee. Around the same time, a French inventor developed the "pumping percolator", in which boiling water in a bottom chamber forces itself up a tube and then trickles (percolates) through the ground coffee back into the bottom chamber. Among other French innovations, Count Rumford, an eccentric American scientist residing in Paris, developed a French Drip Pot with an insulating water jacket to keep the coffee hot. Also, the first metal filter was developed and patented by French inventor.
The Moccamaster isn't for everyone. Handmade in the Netherlands, it costs around $300—and would never win an award for value. It lacks a programmable timer, and it was also bit more difficult to set up than the rest of the coffee makers—in fact most were ready to go right out of the box. But a quick look at the instruction diagram should clear up any confusion, and the end result is well worth the effort.
From there, it’s up to your personal preference. Arabica beans have a higher acidity, with notes of fruit and berries. Robusta beans are darker and richer, with more caffeine. Different levels of roasts — light, medium, dark — determine how much of the beans’ oils will break through the surface of the bean, which also affects acidity, flavor, and caffeine levels. “Get to know your local coffee expert,” recommends Awan. Nothing beats a conversation with a barista or local coffee roaster who can help you try different beans and roasts, and to experiment with those variables in real time. Finding your favorite is all part of the fun.
Throughout the latter part of the 20th century, a number of inventors patented various coffeemaker designs using an automated form of the drip brew method. Subsequent designs have featured changes in heating elements, spray head, and brew-basket design, as well as the addition of timers and clocks for automatic-start, water filtration, filter and carafe design, and even built-in coffee grinding mechanisms.
This Good Housekeeping Seal star features an all-black body, a 12-cup glass carafe, a reusable filter and a backlit LCD screen with digital touchpad controls. You can program the clock to automatically brew coffee in the morning. It'll make a hot pot very quickly, but drink up — the keep warm feature didn't keep the coffee as warm as other models in our tests.
Domestic electrification simplified the operation of percolators by providing for a self-contained, electrically powered heating element that removed the need to use a stovetop burner. A critical element in the success of the electric coffee maker was the creation of safe and secure fuses and heating elements. In an article in House Furnishing Review, May 1915, Lewis Stephenson of Landers, Frary and Clark described a modular safety plug being used in his company's Universal appliances, and the advent of numerous patents and innovations in temperature control and circuit breakers provided for the success of many new percolator and vacuum models. While early percolators had utilized all-glass construction (prized for maintaining purity of flavor), most percolators made from the 1930s were constructed of metal, especially aluminum and nickel-plated copper.
Some home pump espresso machines use a single chamber both to heat water to brewing temperature and to boil water for steaming milk. However, they can perform only one operation at a time, requiring a warm up period between the execution of espresso pull and the milk frothing process. Since the temperature for brewing is less than the temperature for creating steam the machine requires time to make the transition from one mode to the other. Moreover, after the brewing process, a single boiler will expel (usually minor) quantities of water through the steam wand that were left over from brewing, which can cause the steam heated milk to then have a slightly watered down taste. To avoid this, the leftover water needs to be collected from the steam wand before steaming of the milk should begin. SB/DUs are generally found within the lower tiers of enthusiast home models, with steam wands being a simple and valued addition.
“What I REALLY like about it is that it’s pretty much an all-in-one system without the thousand-dollar-plus all-in-one cost. I push one button and all the magic happens, and it’s quite entertaining to watch the espresso cascade through the milk and create separate layers. I also like that I can take the milk and store it in my fridge. I’ve done some temperature tests, and only noticed a five-degree increase after making a double latte, before I put it back in the fridge. This is nice, as you would think that to be so close to all that heat, it would be a much bigger temperature fluctuation.”
Although it's very easy to use — you just fill the portafilter with grounds, attach it to the machine, and press the button to start — The Gaggia Classic isn't as flexible or intuitive as the Breville Barista Express. The user manual is less detailed, too, so you have to have a basic idea of what you're doing or browse the internet for tips. The machine has a one-year warranty if you run into problems.
From there, it’s up to your personal preference. Arabica beans have a higher acidity, with notes of fruit and berries. Robusta beans are darker and richer, with more caffeine. Different levels of roasts — light, medium, dark — determine how much of the beans’ oils will break through the surface of the bean, which also affects acidity, flavor, and caffeine levels. “Get to know your local coffee expert,” recommends Awan. Nothing beats a conversation with a barista or local coffee roaster who can help you try different beans and roasts, and to experiment with those variables in real time. Finding your favorite is all part of the fun.
“My mom gave me a Gevalia 12-cup, programmable coffee maker a few years ago, and it’s gone with me through multiple Brooklyn apartments. It’s hard to find now, so if it ever breaks, she has a killer Cuisinart DCC-1200. I actually look forward to her coffee every time I’m home. It makes a mellow brew. If my Gevalia machine ever gives out on me, I’ll upgrade to that.” — Allie LaPorte, wine representative, Wilson Daniels
CR’s take: Our highest-rated drip brewer with an insulated, thermal carafe, the Ninja Bar Brewer CF085 has plenty to recommend it. CR’s testers find that it offers superb brew performance and is very easy to use. In our member surveys, Ninja drip coffee makers received an Excellent rating for owner satisfaction. (We don’t yet have enough data to judge reliability.) This model has a full suite of features, including an unusual over-ice brew mode for making iced coffee. Ninja claims its thermal carafe will keep coffee hot for 2 hours, and the machine comes with a milk frother and a standalone French-press brewer. These features come at a price, of course; the Ninja Bar Brewer is the second most expensive model on this list.
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