Some machines use a single boiler kept at steaming temperature, but water for brewing is passed through a heat exchanger, taking some heat from the steam without rising to the same temperature. Although the water for brewing remains at a lower range than that required for steaming milk, it is still too hot for proper coffee extraction without first cooling; thus this type of machine requires a cooling flush of 4–6 seconds prior to the first espresso pull. Once the machine is dialed into the proper temperature, as many shots can be pulled as required without refreshing. However, if the user leaves the machine idle again for some period, the flushing process will need to be repeated. The HX variety is found in many mid-range machines and many users install thermometers to assist them is dialing in correct temperatures. There is some controversy as to the temperature stability of the brewing water, since it is indirectly converted from steaming temperature to brewing temperature, rather than kept at a brewing temperature.
The method for making coffee in a percolator had barely changed since its introduction in the early part of the 20th century. However, in 1970 General Foods Corporation introduced Max Pax, the first commercially available "ground coffee filter rings". The Max Pax filters were named so as to compliment General Foods' Maxwell House coffee brand. The Max Pax coffee filter rings were designed for use in percolators, and each ring contained a pre-measured amount of coffee grounds that were sealed in a self-contained paper filter. The sealed rings resembled the shape of a doughnut, and the small hole in the middle of the ring enabled the coffee filter ring to be placed in the metal percolator basket around the protruding convection (percolator) tube.

The Baratza Encore is simplicity defined and our top coffee grinder. This burr grinder has a 40-setting grind size selector, an on-off switch for continuous grinding, and a push-button for manual control. That's it. Other grinders include complicated timers, built-in scales, strength adjustment sliders, and other doodads, but Baratza suggests that you don't need them—and they're right. Measure your beans using a separate scale, grind them fresh for each cup. That's the way to do it.
The Mr. Coffee Optimal Brew coffee maker System has a highly modular design, with its rectangular water reservoir easily sliding in and out of the chassis. For those who only want a cup of basic coffee, you will find that the Mr. Coffee Optimal Brew coffee maker System will do that very well – its "brew now" button is found on the front of the machine.
The built-in burr grinder is high quality, and you can easily adjust the grind size and amount with a dial on the front of the machine. You can choose to use either a single- or double-wall filter basket, and the grinder will automatically adjust to give you the right about of coffee grounds for your brew. Reviewers love that it comes with the grinder and praise its quality.
Wake up to a perfect cup of coffee with Bunn’s newly designed 10-Cup HB Heat N' Brew Programmable Coffee Maker. For over 60 years Bunn has consistently and reliably brewed great tasting coffee for millions of people in their favorite restaurants and cafes. You can count on the brewing experts at Bunn to help you make the same great tasting coffee at home for your family, friends or just for you. This coffee maker features a digital clock with a programmable brew start time. Heat N’ Brew...
The first machine for making espresso was built and patented by Angelo Moriondo of Turin, Italy, who demonstrated a working example at the Turin General Exposition of 1884. He was granted patent no. 33/256 dated 16 May 1884 (according to the "Bollettino delle privative industriali del Regno d'Italia", 2nd Series, Volume 15, Year 1884, pages 635 – 655). A certificate of industrial title was awarded to Mr. Moriondo Angelo, of Turin, for an invention called "New steam machinery for the economic and instantaneous confection of coffee beverage, method 'A. Moriondo', Plate CXL".
Why it's great: A true espresso drinker knows that when it comes to espresso, there are a few things that can't be overlooked when it comes to a quality cup: freshness and a good grinding method. The burr grinder is a known Barista-favorite, as it maximizes the surface area of the grinds resulting in optimal flavor. The BES870 even allows you to adjust the grind and portion size, so you can go from fine to course depending on your desired flavor. 
It’s not that cone filters won’t make a great cup of coffee — the OXO On 9-Cup still ranked fifth out of 10 in our taste test. But flat bottoms generally allow for the grounds to be more evenly extracted and increase the coffee’s flavor. (It’s no coincidence our other three recommendations have flat-bottom brew baskets). You may have to do a little more tweaking to get this coffee maker’s brew to the best it can be, and that’s the other reason we like the 12-cupper more. This smaller version doesn’t let you tinker with water temperature.
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.