The Best Coffee I’ve Ever Tasted Comes out of a Dirty Sock
If you’ve browsed any of our coffee coverage, you know that we take our brew pretty seriously. From pour-overs to espresso machines, and from bean roast to brew strength, we have strong opinions about it all. This week, it’s all things coffee at Wirecutter.
As the former owner of a café specializing in third-wave coffee, I’ve had the chance to experience coffee brewed dozens of ways: every kind of pour-over and espresso, AeroPress, Vietnamese phin drip, moka pot, siphon, and more. My all-time favorite coffee, though, comes from the nel drip pot—also referred to by Wirecutter founder Brian Lam as the “dirty-sock method” (when he feels like ragging on me in Slack).
Fundamentally, the nel drip is a pour-over setup like a Chemex, a Kalita Wave, or a Hario V60. The big difference is that instead of paper or metal, it uses a flannel sock to filter the coffee. But the magic of the nel pot is in how you use it. Although you can treat your nel like any other pour-over device, you’ll get the best, most distinctive results when you brew the traditional way—a way that flies in the face of common coffee-brewing knowledge.
Freshness is highly prized among coffee snobs, whereas nel drip is usually made with beans that most people would consider irretrievably stale—a month or more past roast. (Conventional wisdom says that beans are at their best a few days after roasting.) When coffee first came to Japan via Dutch traders, it was months old by the time it arrived. Early Japanese coffee enthusiasts found that with a huge dose of coarse grounds, relatively tepid water, and a very slow pour, the nel was capable of getting remarkably deep flavor out of decrepit beans.
The cooler water (typically around 175 degrees Fahrenheit), the coarse grind, the high coffee-to-water ratio, and the slow pour create a concentrated brew of wildly under-extracted coffee. That might sound bad, but under-extraction is actually a prized (and as this video shows, prize-winning), technique for some baristas since they believe it highlights coffee’s finest flavors and aromas. The nel drip isn’t the only way to achieve this effect—people have applied low-temp, high-ratio principles to AeroPress and other methods—it's just my favorite. Research firm Gastrograph performed an analysis of sensory survey data from both traditional pour-over and nel preparations and found that nel drinkers reported stronger notes of fruitiness, earthiness, richness, bitterness, and minerality, as well as reduced perception of woodiness and spiciness.
Whether the sock itself has much to do with that difference is a subject of debate, but Michael Phillips, Blue Bottle Coffee’s director of coffee culture, told me that compared with a traditional paper filter, a cloth filter “allow[s] for more softness and round edges in a cup’s profile.”
It’s also unclear whether you must use old coffee to make a proper nel cup. I usually have old beans hanging around, but in some cases I’ve used fresh coffee with the nel method, and to my palate the results have been just as good. In other words, the fact that you can use nel with old coffee is a plus, not a limitation.
My go-to recipe comes from Blue Bottle, whose founder James Freeman is a nel drip stan. It uses a ridiculous 3.7:1 ratio—185 grams of water to 50 grams of coarse grounds. The brew is spread out over three slow pours (45, then 60, then 30 seconds) and two rests (45 and 20 seconds) for a total of 3 minutes and 20 seconds of drip-dropping, resting, drip-dropping, resting, and drip-dropping again. It’s a painstaking, methodical process, and it makes only one cup. But the coffee it produces is divine, like a shot of espresso from an alternate dimension—rich, velvety, sour-sweet, and intensely aromatic. It’s also especially concentrated. I savor it like an 18-year scotch.
Fifty grams of coffee is a lot for a single, small cup. It’s not something most people (myself included) can realistically afford as an everyday indulgence, especially when using beans from an artisan roaster (my latest love affair is with Atlas Coffee Club). So to get my money’s worth out of the nel—and to keep my coffee gear from spilling out of its cupboard and colonizing the rest of the kitchen—I also use it for a more conventional, much cheaper preparation that gives me results closer to what a Chemex produces. Regardless of how you use it, the nel makes a damn fine cup of coffee (video). Just make sure to change your socks every once in a while.
A cloth filter takes some getting used to, but it can produce a much more flavorful brew.