Pierce's design was later improved by U.S. appliance engineers Ivar Jepson, Ludvik Koci, and Eric Bylund of Sunbeam in the late 1930s. They altered the heating chamber and eliminated the recessed well which was hard to clean. They also made several improvements to the filtering mechanism. Their improved design of plated metals, styled by industrial designer Alfonso Iannelli, became the famous Sunbeam Coffeemaster line of automated vacuum coffee makers (Models C-20, C-30, C40, and C-50). The Coffeemaster vacuum brewer was sold in large numbers in the United States during the years immediately following World War I.
An electric drip coffee maker can also be referred to as a dripolator. It normally works by admitting water from a cold water reservoir into a flexible hose in the base of the reservoir leading directly to a thin metal tube or heating chamber (usually, of aluminum), where a heating element surrounding the metal tube heats the water. The heated water moves through the machine using the thermosiphon principle. Thermally-induced pressure and the siphoning effect move the heated water through an insulated rubber or vinyl riser hose, into a spray head, and onto the ground coffee, which is contained in a brew basket mounted below the spray head. The coffee passes through a filter and drips down into the carafe. A one-way valve in the tubing prevents water from siphoning back into the reservoir. A thermostat attached to the heating element turns off the heating element as needed to prevent overheating the water in the metal tube (overheating would produce only steam in the supply hose), then turns back on when the water cools below a certain threshold. For a standard 10-12 cup drip coffeemaker, using a more powerful thermostatically-controlled heating element (in terms of wattage produced), can heat increased amounts of water more quickly using larger heating chambers, generally producing higher average water temperatures at the spray head over the entire brewing cycle. This process can be further improved by changing the aluminum construction of most heating chambers to a metal with superior heat transfer qualities, such as copper.
Bunn-O-Matic came out with a different drip-brew machine. In this type of coffeemaker, the machine uses a holding tank or boiler pre-filled with water. When the machine is turned on, all of the water in the holding tank is brought to near boiling point (approximately 200–207 °F or 93–97 °C) using a thermostatically-controlled heating element. When water is poured into a top-mounted tray, it descends into a funnel and tube which delivers the cold water to the bottom of the boiler. The less-dense hot water in the boiler is displaced out of the tank and into a tube leading to the spray head, where it drips into a brew basket containing the ground coffee. The pourover, water displacement method of coffeemaking tends to produce brewed coffee at a much faster rate than standard drip designs. Its primary disadvantage is increased electricity consumption in order to preheat the water in the boiler. Additionally, the water displacement method is most efficient when used to brew coffee at the machine's maximum or near-maximum capacity, as typically found in restaurant or office usage. In 1963, Bunn introduced the first automatic coffee brewer, which connected to a waterline for an automatic water feed.
If you don’t have the time or want to build a highly customized taste for your espresso mixes and just want a great tasting cup of espresso, super-automatic espresso makers are going to be your best bet. While you do give up some of the control you have over the final product, a super-automatic espresso maker automates almost all of the process for you, meaning that you can just get a great shot of espresso without having to do any extra work. This makes it perfect for people on the go or who prefer convenience over control.
The next is the machine’s auto-pause. If you remove the carafe before your full pot is done brewing, the flow will stop until the carafe goes back in. It’s not a perfect system. There are a few inevitable drips that add an extra step to clean-up, and if the water is held up in the brew basket for too long, it increases the chance of over-extraction. But if you want a great first cup to sip on while the rest of your pot is brewing, you’ll get it in a much more satisfying time frame.
“Small things CAN bring you joy. My recent purchase of this Zojirushi coffee maker has made me very happy. Sounds like a commercial, but consider this … Last year, I bought a more expensive coffee maker that made terrible coffee! Instead of using the machine, I started making pour-overs. Something I hate to do … A year and a bunch of customer reviews later, I ordered this new baby, and I am so happy, I am writing about it here. I don’t know if it’s the water filter that water passes through or the fact that the water is introduced to the coffee a little bit differently, but the result is what I consider a perfect cup of coffee.”
Why it's great: Flair *really* stresses how important espresso as an "art form" really is. The Flair is for someone who genuinely enjoys the process of creating espresso. It's unique design makes it appealing on the counter or wherever you decide to take it, since it disassembles and folds up nicely into a carrying case. Since it doesn't require electricity, you can take this fancy piece of hardware anywhere. The only downside is that you have to buy your own burr grinder for the best results, but chances are this won't be an issue for someone who is already gung-ho about "the process."
“This little coffee maker is PERFECT! So easy and reliable. It works great for a household with little kitchen space and light coffee drinkers. It has upped my coffee intake because it’s so easy to make coffee now! Plus, to be able to have it waiting in the morning and encourage me to actually get out of bed on time is well worth the price of this little machine.”
“On mornings when I don’t make a pour-over (weigh out the water, the beans, all that fun stuff), the Capresso drip machine yields the cleanest-tasting cup that brings out beans’ floral flavors, without burning the grinds or yielding an overly acidic cup. It’s also got a built-in, conical burr grinder, which saves you from having to buy a separate gadget, too.” — Kat Odell, author of Day Drinking
In terms of maintenance, more complex machines tend to require more cleaning. Accessories like pumps, boiler setups, and thermostats usually forecast the amount of cleanup and maintenance that will be required over time. Buyers should be aware that machines with plastic outer coatings can crack with repeated use, leading to the need for expensive repairs or even replacement.
Since semi-automatic espresso makers require you to dose the coffee yourself, grind and pack it, they give the brewer more control. You can tinker and master the art of making espresso. You can learn to pull the perfect shot. Still, fully automatic machines are a good option for someone who wants quality espresso at home, but wants to put in less effort (and skill). According to our expert from Students of Coffee—and our own online research—a semi-automatic machine is the best way to make espresso.
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.