I spent most of 2010 learning how to brew coffee using pretty much every technique I could find. I loved some, I feared others, but I didn't really find anything worth sticking with until I used an Able Brewing Kone in my Chemex. With the Kone + Chemex combination, I'm able to make coffee that has the velvety mouthfeel of a French press while retaining the complexity of flavor that I love in a pourover.
The Chemex is a notoriously fickle way to brew a cup of coffee. Because the hole in its neck is so large, Chemex filters need to be thick and heavy paper, which imparts a strong paper taste to the coffee and removes many of the tasty oils. At the same time, the brewing basket is enormous--making it difficult to control the amount of time the water spends in contact with grounds while simultaneously cooling off the coffee too quickly. While you can make an awesome cup of coffee with a Chemex and its paper filters, it's difficult to do with any consistency. If you want to brew coffee using a pourover device and a paper filter, a Hario V60 or one of those plastic Melitta cones are both better than the Chemex.
At least, this is what I thought until I learned to use the Able Brewing Kone.
The Kone was designed by Keith Gehrke, then of Coava Coffee in Portland, to be a reusable stainless-steel conical filter designed to fit into a Chemex carafe. With thousands of tiny etched holes, the Kone lets coffee--complete with oils and a bit of particulate--through. As I said before, the result is a cup of coffee with the mouthfeel of a French press and the delicate, complex flavor of a pourover.
To use the Kone properly, you need to modify your typical pourover technique. First, you want to grind your coffee much more finely for the Kone than you would for a paper filter pourover. When you're adding water to the brew basket, you want to agitate the grounds as little as possible. Typically, this means trickling the water as slowly as you can into one spot in the center of the Kone. If you treat the Kone like a traditional pourover, grinding coarsely and agitating the grounds with your stream of water, the water won't linger in the basket long enough and you'll end up with weak, underextracted coffee. Trust me, I learned this the hard way.
The magic of the Kone is that the finely ground coffee actually serves as a filter as well, this lets the brewing coffee linger longer in the basket and drain evenly from all parts of the filter. To really get the most out of the Kone, a pourover kettle, like the Hario Buono is necessary to get precise control over water flow and placement. As always, a good grinder is a necessity as well.
For reference, the ratio recommended by Able is what I recommend when using the Kone. Grind 25g of coffee, fine to medium fine. To the coffee, I add 400g total of water, with a one minute pause after the grounds are fully wet to let them bloom. I add the remainder of the water as slowly as I can, it typically takes between two and three minutes.
Keith Gehrke is going to be at the SCAA show later this week, showing off the third revision of the Kone. We'll be sure to catch up with him there.