The single-serve or single-cup coffeemaker has gained popularity in recent years.[5] Single-serve brewing systems let a certain amount of water heated at a precise temperature go through a coffee portion pack (or coffee pod), brewing a standardized cup of coffee into a recipient placed under the beverage outlet. A coffee portion pack has an air-tight seal to ensure product freshness. It contains a determined quantity of ground coffee and usually encloses an internal filter paper for optimal brewing results. The single-serve coffeemaker technology often allows the choice of cup size and brew strength, and delivers a cup of brewed coffee rapidly, usually at the touch of a button. Today, a variety of beverages are available for brewing with single-cup machines such as tea, hot chocolate and milk-based specialty beverages. Single-cup coffee machines are designed for both home and commercial use.
This testing was designed to highlight the difference in how each machine extracted its coffee grounds. Remember, extraction is tied to water temperature, how long the grounds had to steep, and how evenly that water is distributed in the brew basket. (Depending on how the machine distributes the water and the shape of the basket, any particular ground may or may not receive the same amount of time in contact with water — thus any individual grind may be over-extracted, under-extracted, or just right.) Properly extracted grounds would have a balance of notes and aromas, from slight hints of acid to a pleasant amount of bitterness.
If you’re shopping for coffee at the grocery store, “check the roast date, rather than the ‘best by’ date,” says Awan. With mass market roasters, the “best by” date can obfuscate the window in which coffee beans are at their best: about 4 days after roasting, when some, but not all, of the carbon dioxide has escaped from the beans. (Too much carbon dioxide captured within beans tends to create uneven extraction, as the gas escapes — this is what pre-infusing tries to counter. Conversely, too little carbon dioxide in the bean can lead to a loss of flavor.)
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.