Water quality also plays a massive role in the way your coffee tastes. As we discovered in our review of the best water filters, water isn’t tasteless. Total dissolved solids (TDS) are what give “good tasting” water its sweetness — in fact, the SCAA recommends water with 150 milligrams per liter of TDS to brew coffee. (Want to check your water? A TDS reader is only about 15 bucks.)
Drip-style coffee makers already have a bit of a flavor handicap when compared with other brewing methods, like pour-over and French press, which give coffee drinkers ultimate control over every aspect of the brewing (and therefore extraction) process. This makes it even more important to select a high-quality coffee bean for your at-home drip coffee maker. To learn more, we spoke with Saadat Awan at Woodcat Coffee in Los Angeles.
All the machines we tested came with either insulated carafes or glass pots with built-in warmers. Both have pros and cons. Glass pots are typically easier to clean because they tend to have wider mouths, and the lack of internal insulation means that glass pots will have a greater interior volume relative to its exterior volume — basically, it’s easier to get your hand or dish sponge into a glass pot. On the other hand, glass pots are more fragile and have to be heated from a base plate. In our tests, those base plates could even raise the temperature of the coffee, like with the CuisinArt, which can make coffee taste burnt.
The principle of a vacuum brewer was to heat water in a lower vessel until expansion forced the contents through a narrow tube into an upper vessel containing ground coffee. When the lower vessel was empty and sufficient brewing time had elapsed, the heat was removed and the resulting vacuum would draw the brewed coffee back through a strainer into the lower chamber, from which it could be decanted. The Bauhaus interpretation of this device can be seen in Gerhard Marcks' Sintrax coffee maker of 1925.
Once you start brewing, it makes a really, really good pot of coffee. Our taste test revealed the OXO On 12-Cup coffee was “dark and strong” and appealed to the more traditionalist coffee palates. The great flavor comes from the brewing process. The OXO machines have wide shower heads with multiple ports through which water streams, dispersing it evenly throughout the brew basket. Lots of other coffee makers spout water through just one hole, or through shower heads with a smaller radius, which can increase the chances of uneven extraction.
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.