The catch was math. Here’s a one-paragraph explanation: Many espresso-making grinders have hundreds of grind options, while something like the Uniform or a Baratza Encore has a more modest value of 40. A classic espresso-making recipe is a one-to-two ratio, so if you grind 18 grams of beans, you should be able to make a 36-gram shot in about 25 to 30 seconds. Since this fine adjustment was missing, this was not always possible with the uniform. But by adjusting the amount of beans I start with and keeping the ratio, say 15 grams of beans and stopping the shot at 30 grams, I could get it to work at just the right time. It was a little tedious, but kinda fun to figure out.
From there I went to the Seattle lab of WIRED friends Sam Schroeder, co-owner of Olympia coffee roastery, and Reyna Callejo, Olympic Director of Training and Innovation. I had hoped this would be a machine that could do it all and those hopes were quickly dashed.
The espresso test was almost over when it began. I was keeping abreast of my findings and wanted to see what they found and they ran into the same problem as me. With their Big Truck Bio Mixture, grind level five was far too fine and the coarser sieve was poured far too quickly.
“Two steps make a difference of 25 seconds,” Reyna remarked, perhaps sensing a problem. “That is a lot!”
Step six was the only option from then on, and the shot Reyna drank came out too quickly, meaning it was under-extracted, completing the espresso test.
“We give people a weight of beans and say, ‘Adjust your grind,'” Sam explained. “You can’t do that with this machine.”
“But wait,” I howled. “You can change the weight of the beans and adjust the shot size.”
“That’s a lot of math for your morning,” Sam countered, and the more I thought about it, the more I agreed. We want to control the size of the coffee we make at home, not be dictated by our grinder.
It got better from there. Even when things went wrong with the espresso, they discovered that it was a regular-retention grinder, meaning that if you grind 18 grams of beans, you’ll get almost 18 grams of coffee grounds out. Sometimes, especially with flat grinders where gravity doesn’t help, coffee grounds get lost in the machine or in the grounds container, meaning you’re losing money every time you grind. There is even a mill called niche zero is designed in such a way that no dirt remains (or is retained) in the machine.
But as much fuss as we had to make espresso, the pour-over, which Reyna describes as “the second most difficult type of coffee to make,” was done. Wilfa recommends grinding it between steps 14 and 28. Sam ground in step 24 to use with a Kalita Wave dripper and the coffee came out perfect, with an extraction of 20.36 percent (they like between 18 and 22 percent) and with a total dissolved solids (TDS) of 1.40 percent. For french press folks like yours, the grind was pretty coarse and when I made it at home it was intensely flavorful and not too mushy. Dead easy.