I test many coffee machines for a living. This one must stay

Coffee is the Original desktop biohack and the country’s most popular productivity tool. As we lose sleep over the switch to Daylight Saving Time, the caffeine-addicted WIRED Reviews team writes about our favorite coffee-making routines and devices that will keep us alert and maybe even happy in the morning. Today, critic Matthew Korfhage explains his enduring love of filter coffee and why the Ratio Four never leaves his counter. In the coming days we will add more Java.Base Stories about other WIRED writers’ favorite brewing methods.

As with any Although it’s worth it, a morning coffee routine can take on the character of religion. And like many religions, it is often born as much by chance as by moral conviction. My name is good old-fashioned filter coffee. It’s what I drink first, before even thinking about making espresso.

I’m WIRED’s senior coffee editor and have developed a deep fondness for the many variations of coffee, Since espresso has Aeropress has cold brew. But “coffee” to me, deep in my soul, always means a steaming cup of pure juice. Fortunately, it is also the coffee sector that has been most transformed by technology in recent years. Coffee filters from Ratio Four Coffee Maker (now quietly on its second generation) seems to me to be the purest form of coffee, the liquid distillation of the smell of my coffee beans fresh from the grinder.

My love for filter coffee began when I was a teenager, traveling and studying in India – perhaps my first taste of adult freedom. This is where I had the first full cup of coffee that I remember finishing. In Jaipur, filter coffee was an intense, jet-black brew, usually mixed with milk and sugar. I decided that if I was going to drink coffee, I would take it straight and learn to love it on its own terms. A new friend, pouring jaggery into his own brew, mocked my insistence that I didn’t want sweetened milk. I then drank a cup so thick and strong and so caffeinated that my hair stood up perpendicularly. If I had made a mistake, I refused to admit it.

I brought this preference back to Oregon, drinking purely black and terrible drip coffee at all-night dinners and filthy office break rooms. Black coffee had become a morality clause, although it was hardly a matter of taste.

It wasn’t until years later that I discovered that filter coffee could actually be just as refined a pleasure as a pinky espresso.

Increase drip

This was partly a technological problem. Aside from a classic Moccamaster, it’s only very recently that home drip coffee makers have been capable of producing a truly excellent cup. For years, I didn’t keep any in my house.

What introduced me to the possibilities of drip was a new wave of coffee shops in Portland, early pioneers of third-wave coffee. Stumptown Cafe and then above all Heart Coffee Roasters in Portland. Heart’s Norwegian roaster-owner Wille Yli-Luoma explained to me at length about the aromatic purity of lightly roasted immersion coffee—the fruity aromas of a premier Ethiopian coffee that might smell of peach, nectarine, or blueberry. The Scandinavians have long enjoyed it, he told me, and have turned lightly roasted coffee into a pure craft. America was finally catching up.

Yet I could never get the same flavor or clarity on a home brewer. Not until recently. To get the best version, I still had to walk up the street to Heart and get my coffee from the guy who roasted it. Or I had to spend way too much time running water over coffee through a cone filter. I rarely felt like doing this when I was still fuzzy from sleep, already late for work.

What it took was a brand new generation of filter coffee makers modeled after pour-over coffee, with agitating shower heads, strict temperature control, and a “bloom” phase that wets the coffee grounds and allows the coffee to release its carbon dioxide and extract it more completely. A new generation of machines from manufacturers like Bonavita and Oxo has sparked a revolution in at-home filter coffee that is now in full swing.

The machine I use to test coffee

My most used machine lately is the Four Small Batch Coffee Maker from the Portland company Ratio. I spend a lot of time testing coffee and espresso machines. And so the machine on my counter spins often, depending on what new machine comes my way. The cafe also rotates quite often.

But it’s the Four that rarely leaves my counter after having tried almost every high-end filter coffee maker on the market. There are machines, like Friend Aiden and the xBloom Studiowhich have much more versatility and customization to get the perfect cup for each person. What I love about The Four is that it’s made for my natural routine. I only brew a cup or two at a time, and the Oven is optimized for eight- or 16-ounce batches. It also allows for rich extraction without requiring me to play around with every new bean I try.

The Four steeps for a long time, just over five minutes for a full 20-ounce batch, with a flowering cycle that’s also quite patient. It’s a smooth, even, full-bodied extraction – perhaps the best-tasting drip coffee maker I’ve ever had when brewing a single 10-ounce cup. A classic Technivorm Moccamaster KBGV (see here on Amazon) can offer somewhat crystal-clear accuracy. It has a clean taste. But the Four seems to unlock a coffee’s deepest secrets and unveils flavors you didn’t know existed. It is also reliable and repeatable, just like a Moccamaster. Two batches brewed in a row, with the same coffee and the same grinder on the same setting, generally have the same character.

On the white machine in particular, I admit it’s difficult to keep coffee stains out of the ribbed brew chamber, which signals coffee oil buildup. This requires monthly soaking in water with Urnex Cafiza Coffee Cleaning Powder to avoid unpleasant flavors. The lack of an anti-drip system also forces me to wipe the base after removing the carafe, due to the inevitable stray drips.

The Four is also a coffee maker that wants you to drink immediately. It comes out at drinking temperature and there is no thermal carafe. If one of the main things you want from your first sip is devilish heat, I’d refer you to the Aiden or Moccamaster. But I actually prefer the Oven serving temperature, which mimics pouring. I prefer not to let my coffee cool and oxidize until it reaches my preferred temperature of 150 degrees Fahrenheit, when the coffee’s aromas and perceived sweetness reach their optimal balance.

This all adds up to make Ratio Four what I use most often when tasting beans from a new coffee subscription service I’m trying. When paired with a precise flat burr grinder, these days it is the Mazzer Philos—I can taste the comforting clarity of aromas locked within each bean. The chocolate notes taste like chocolate grown in a specific location. Strawberries taste like strawberries. Snozzberries taste like snozzberries.

This is a far cry from my first cup full of anger in Jaipur. But maybe that’s ultimately what I wanted back then, when I decided as a teenager that loving coffee meant loving it only in its purest form.