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.
CR’s take: The Cuisinart Coffee on Demand is a self-serve model. It stores 12 cups of brewed coffee in a reservoir and has a dispenser instead of a carafe. It makes sense in homes where people are drinking coffee at different times; it keeps coffee hot and ready, so family and guests can fill their own cups. This model is programmable and features a water filter and a cleaning indicator. The reservoir can be removed for washing. In our tests, the Coffee on Demand performs quite well, receiving a Very Good rating for convenience. At less than $100, it can be a terrific choice for entertaining.
In our quest to find the best, we pitted 10 highly regarded coffee makers against each other. These are the machines that regularly make it on best-of lists, earn accolades, and/or are recommendations from the coffee experts we talked to over the course of this review. We aimed for multi-cup carafes — no single serves — and drip machines only. (We didn’t want to muddy the results with French press, pour-over, or espresso. Those are for other reviews.)
If your busy life keeps you from making coffee by hand, you can also consider a capsule machine such as a Nespresso coffee maker. These machines use small capsules or pods of coffee, so you don’t have to worry about measuring grounds and adding them to your device. Simply add a capsule, fill up the reservoir and press the On button. If you’re more of a traditionalist, a stovetop espresso maker might be the right option for you. This type of maker uses your stove to heat up water, which then steams up and passes through a capsule of grounds above the reservoir. The steamy espresso then collects in an upper reservoir at the top of the maker. These espresso makers are very popular in Europe and require no electricity to function.
Our brew-performance tests measure the brew temperature and contact time (how long water stays within a sweet spot of 195° to 205° F for brewing). We measure concentration using a refractometer, a device that measures the amount of coffee dissolved in each brew. Our convenience tests look at how easy it is to set timers, fill the reservoir, clean the machine, and more. And for the first time, we’re incorporating predicted reliability and owner satisfaction ratings into the new Overall Score for each model. We determine these ratings for each drip coffee maker brand using survey data collected from thousands of CR members.