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.[1] 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.
Prior to the introduction of pre-measured self-contained ground coffee filter rings, fresh coffee grounds were measured out in scoopfuls and placed into the metal percolator basket. This process enabled small amounts of coffee grounds to leak into the fresh coffee. Additionally, the process left wet grounds in the percolator basket, which were very tedious to clean. The benefit of the Max Pax coffee filter rings was two-fold: First, because the amount of coffee contained in the rings was pre-measured, it negated the need to measure each scoop and then place it in the metal percolator basket. Second, the filter paper was strong enough to hold all the coffee grounds within the sealed paper. After use, the coffee filter ring could be easily removed from the basket and discarded. This saved the consumer from the tedious task of cleaning out the remaining wet coffee grounds from the percolator basket.
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.
If you’re ready to drop serious money on a high-quality espresso machine that produces smooth, complex shots, our pick is the Rocket Espresso Appartamento Espresso Machine. The machine lets you cycle quickly between steaming milk and pulling espresso: It uses a heat exchanger, rather than the more typical thermoblock, which means that the Rocket’s boiler heats all the way up to milk-steaming temperatures when you first turn it on. When you’re ready to pull shots, the heat-exchanger sends a burst of cool water through a copper tube in the boiler, bringing the temperature briefly back to espresso-friendly levels before heating back up.

"A rare example of the meeting of form and function. This machine is both beautiful to look at and makes wonderful delicious espresso and cappuccino. I was hesitant to spend this much on a "coffee maker", but took into consideration what it costs to get a decent cappuccino from a cafe or Starbucks and finally gave in. Boy am I glad I did. All it takes to get me out of bed in the morning is the happy thought of pulling yet another delicious shot from this wonderful machine."
The OXO is SCAA-certified, so we knew going in that it would heat water to the right temperature range and let coffee brew for the right amount of time. But what really sold us on the OXO was how its scrolling dial made even that customizable. Assuming you want to bring the extraction down a touch for lighter, subtler coffee, you can lower the water temperature with a twist of the dial. Likewise, if you want a slightly more robust aroma from your brew, you can increase the water’s temp the same way.
This product is their smallest K-Mini™ K15 Single-Serve K-Cup Pod Coffee Maker, but it still delivers the delicious taste and reliable quality you expect. Its small size ensures the K-Mini™ coffee maker is perfect for kitchens with limited counter space, college dorms, and other small spaces. Its portable design makes it easy to transport anywhere you go, so your favorite beverages are never far away. Whether brewing coffee, tea, iced tea, or hot cocoa, the product makes single-cup brewing...
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.
CR’s take: If you’re an aficionado of fresh ground coffee, this Black+Decker is the brewer to buy. As the name suggests, the Mill & Brew goes that extra mile, grinding whole coffee beans just before brewing. As a result, the machine is capable of making a great pot of coffee. Made of plastic with stainless steel accents, this model is easy to use and to clean, earning a Very Good rating in our convenience tests. It allows you to adjust brew strength, and it’s programmable, so you can set it to grind and brew just before you wake up.
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