An early variant technique, called a balance siphon, was to have the two chambers arranged side-by-side on a sort of scale-like device, with a counterweight attached opposite the initial (or heating) chamber. Once the near-boiling water was forced from the heating chamber into the brewing one, the counterweight was activated, causing a spring-loaded snuffer to come down over the flame, thus turning "off" the heat, and allowing the cooled water to return to the original chamber. In this way, a sort of primitive 'automatic' brewing method was achieved.
The single-serve or single-cup coffeemaker has gained popularity in recent years. 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.
In terms of maintenance, more complex machines tend to require more cleaning. Accessories like pumps, boiler setups, and thermostats usually forecast the amount of cleanup and maintenance that will be required over time. Buyers should be aware that machines with plastic outer coatings can crack with repeated use, leading to the need for expensive repairs or even replacement.
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.