I start the day with the new coffee. I’m using the recipe of my friend. The second try is already good enough to be enjoyed with my breakfast. Endorphins flood the rests of my brain not already dissolved by caffeine. It’s going to be a good day.

I immediately get to a point where only fine-tuning is needed. I see the light at the end of the tunnel. The coffee is a bit bitter and a bit acidic, but the taste is overall pretty decent. I’m applying my knowledge, turning the nobs and BOOM: Nothing happens. I hit a new wall.

I’m back in a thinking break. Why is my coffee sour AND bitter? In my mental model that’s impossible. I make another coffee. Same problem. But as I clean up after me, I inspect the puck closely and there it is. I see clear signs of channeling.

One side of the puck is clearly darker / wetter than the other. That explains my strange results. I’m over- and under-extracting my coffee at the same time. What a mess. I retry a shot. Same problem.

I overestimated my puck preparation. I need better tools. A WDT tool. A leveling tool. A proper tamper. I’m waiting for them to arrive from Amazon, until then the lab is closed.