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.
“This is the same coffee maker that I bought years ago. And it’s even the same price. Yep — they do still make things like they used to. And they last forever. It’s super simple, super reliable, compact, and cheap. There are a lot of places where we can spend money, but a simple cup of coffee doesn’t have to be one of them. Once you get the amount of water and coffee figured out to your taste — simply do that. No K-cup, nothing to recycle, fits the car cup holder. And the coffee stays hot in the mug.”
When it comes to features, our top pick’s little sister, the OXO On 9-Cup Coffee Maker, looks and feels much the same: a single-button dial, programmable start times — even the timer that lets you know how old the coffee is after it’s been brewed is identical. On this version, the water reservoir isn’t detachable, but it brews coffee significantly faster than the 12-cupper’s 14 minutes(!) and it’s $100 cheaper. It’s a great machine that didn’t earn our top spot simply because the coffee it makes didn’t perform quite as well as the other three top picks in our taste tests, and it doesn’t let you tinker with water temperature and extraction the way the larger machine does.
It can take a little while to get to know the ins and outs of a new coffee maker. In CR’s labs, each drip coffee maker we test brews roughly 65 cups by the time our engineers are through with it. And brewing is just one of many aspects we look at. We test for handling and convenience, too, so you can choose a model that helps you sail through morning madness.