That water is heated in a detachable reservoir that doubles as a kettle. This is a unique feature for a coffee maker, but one we ended up appreciating, especially for households with a mix of tea lovers and instant-oatmeal eaters alongside coffee drinkers. Fill the kettle up, lock it in place, and scroll the dial to the amount of coffee you want brewed. The machine is designed so that, even if you have more water in the kettle than you need, it will brew only the amount you specify. The one thing you actually have to measure with the OXO On 12-Cup is the grounds. Do that right, and it’s pretty much impossible to screw it up.
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.
"Oh my goodness! I never knew such a thing existed. This tiny espresso maker makes great espressos! I have taken this to work with me and everyone is jealous. I mean everyone is jealous for real. I think I even persuaded some of my colleagues to buy one themselves! How funny is that? It's so easy to use. I usually use hot water to begin with and I don't bother with getting it to heat my water for me because that just takes a little bit too long. Holding the button for more than 5 seconds will activate the pressurized pumping gear. It is all electronic so you don't have to make any difficult pumping like in some other smaller products. The coffee comes out just as good as any espresso you can make. And the pods are crazy cheap. I found pods that are literally $0.10 each."
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.
For many of us, the daily grind can't begin until we've had that first cup of piping hot coffee—so the right brewer is at the top of the list. The most basic coffee makers make at least a decent cup, but a little more money buys conveniences such as programmability, a thermal carafe to keep coffee hot longer, settings that let you adjust brew strength, and more.