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.
CR’s take: Though this Bialetti lacks typical drip-machine features such as programming and brew-strength control, it more than compensates with a Very Good rating in our brew performance test and a crisp 8-minute brew time. If you’re the type who sometimes prefers a morning shot of espresso to a cup of joe, this twofer—drip machine beside espresso maker—may be for you. It features a built-in milk frother, a permanent coffee filter, and auto-shutoff. CR does not yet have enough survey data on Bialetti machines to rate them on reliability and satisfaction, but when we do, we’ll add that info to our ratings.

Thank you for this great review. For me, I use Bonavita BV1900TS for about a year and I can say that it is Perfect. It’s equipped with most features that are desirable for home brewing. With this coffee maker, you won’t enjoy high-end functionalities, but you will prepare great coffee every time. The black and stainless finish makes it appear beautiful in your kitchen. The stainless steel lining extends the durability of the machine.
This K-Elite Single-Serve K-Cup Pod Coffee Maker blend premium finish and programmable features together to deliver both modern design and the ultimate in beverage customization. It’s a stylish addition to any kitchen. Features strong brew setting when you want to brew a bolder cup of coffee, and an ice setting to brew hot over ice for a refreshing, full-flavored ice coffee.
It can take a little while to get to know the ins and outs of a new coffee maker. In CR’s labs, each drip coffee maker we test brews roughly 65 cups by the time our engineers are through with it. And brewing is just one of many aspects we look at. We test for handling and convenience, too, so you can choose a model that helps you sail through morning madness. 
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