Wired Review: Ratio Eight Coffee Maker

Daniel Modlin at Wired takes a deep dive on the Ratio Eight.

A few years ago while visiting my friend, I eagerly watched him go through the entire routine of making pour-over coffee in a Chemex. He weighed and ground the beans, then placed the grounds in the filter and "bloomed" them, adding just a few tablespoons of hot water to extract CO₂ and reduce some bitterness. Finally, he poured water in concentric circles through a gooseneck kettle, working with precision and timed accuracy. 

The Chemex, while beloved by coffee people, is one of the more complex ways to brew coffee. While the equipment is simple—just a glass carafe and a filter—the technique is difficult to perfect. As I watched my friend, I wondered, “Is this something anyone would do every day?” But soon enough, I found myself caught up in the routine of making pour-over coffee each and every morning, enamored by both the ritual as well as the elegance of taste when done to perfection.

But perfection in a Chemex is hard to come by. It’s not something I (or my friend) have been able to do well consistently. I’ve tried to be as finicky as they come, but ultimately I've convinced myself that part of the beauty of the Chemex method comes from the rarity of success. It's like baseball: If it works a third of the time, then that’s pretty remarkable. When you fail, you still end up with drinkable coffee, although that’s somewhat debatable. At times, it can be so oily that the coffee can stick to your tongue throughout the rest of the day, or it can even taste like a cup of Mr. Coffee, which is drinkable but disappointing, considering the amount of effort put in. I continued on though, convincing myself that I was learning something about what I did wrong with every brew.

But at a certain point, I accepted that my technique wasn’t improving. Too many variables, not enough constants. Instead of searching for a solution, I resigned myself to settling down to a lifetime of imperfect Chemex batches and wasted artisanal (read: expensive) coffee beans. Then I saw a coffee maker that could make consistently delicious Chemex-style pour-over, staring at me across the room.

The Ratio Eight is a pour-over Chemex-style machine with a built-in robot brain that has been programmed to eliminate human error from one of the most difficult brewing techniques out there. It also looks damn good doing it.

To use the Ratio Eight, fill the water tank to one of the two marked lines for either a half or a full pot. Then, drop a filter into the carafe—either a standard paper Chemex filter or the $40 Ratio Kone, a reusable filter specifically designed for this machine. The Kone can only handle half batches, but a half batch is all my partner and I need each morning. For a whole carafe, you should then add 70 grams of a medium fine ground coffee bean; if you’re making a half carafe, add just 35 grams. Then, slide the glass carafe into place. Because both the carafe and the machine have sensors on it, the machine won’t start up until the carafe is locked in. 

From there, you can either watch or walk away, though watching it brew is half the fun. With the press of a button, the machine begins gurgling water to the exact right temperature (200 degrees Fahrenheit, according to the Specialty Coffee Association of America), pulling it up through internal glass tubing systems.

Just as a manual pour over would, the Ratio first delivers a “Bloom” cycle. The steel showerhead spurts a few splashes of hot water to bloom the grounds, and as the hot water drips down, it simultaneously warms the carafe. From there, the bottom light at the base of the coffee maker pulses to indicate the switch from “Bloom” to “Brew.” Water begins raining down from the steel showerhead located above the grounds, spreading evenly over the coffee and approximating the spiraling pour of a practiced human hand. Ratio founder Mark Hellweg told me that there could have been a rotating head to truly achieve the concentric circle effect, but the company chose the showerhead design because it is less likely to need repairing. A good choice: I have been using the Ratio Eight for almost a year and have never encountered a single problem with the showerhead.

You should be using nice, artisanal, fresh-roasted coffee in the Ratio, not Folger’s. I mean, Folger’s will technically do the trick, but that would be like taking your new Ferrari for a test drive through crowded traffic: You’re not really getting the whole experience. While a properly brewed Chemex can accentuate flavors better than most brewing methods, this machine does it consistently. The beauty of this machine, I think, comes both from the handcrafted materials it is made with as well as the flavor profiles it exposes in your beans. The flavors listed on coffee bags that used to escape me (cherry, vanilla, tobacco) are suddenly vivid. Better yet, I know each and every morning will be filled with them.

The only complaint I have about the Ratio is that, because the carafe is glass and not heated from the bottom of the machine, it isn’t very insulating, which allows your coffee to cool if you don’t drink it. However, this is easily fixed. First of all, drink your coffee faster! Or, you can pour the remainder into an insulated travel mug for later. Or, you can spend $125 on an insulated carafe and dripper from Ratio. That extravagant accessory is not necessary, but if you want something that can keep your coffee hot for up to 90 minutes, it does the trick. Plus, it matches your machine.