After all of those moka pot shots I got out my Bialetti Brikka, which is also a moka pot but one with an important modification. It took two shots to dial it in and the cup was head and shoulders above my best effort with the standard 3-cup Moka Express I'd been using all month. So much easier!
Then, again using the same coffee, a fairly forgiving blend, I pulled a shot on my Robot. I guessed at the grind and the first shot was, oh, maybe twenty times better than what came out of the Brikka. I sort of wish I could take that month back.
The reason I got out my Moka Express 3 in the first place was to measure how varying six parameters affected the finishing temperature. Specifically, I looked at:
- water fill amount
- initial water temperature
- stove setting
These things made the brew finish hotter:
more water --> hotter
more coffee --> hotter
tamping --> hotter
hotter initial water temperature --> hotter
finer grind --> hotter
higher stove setting --> hotter
I installed a temperature sensor and a level sensor in my pot. The temperature sensor was just below the lower screen to measure the temperature of the water just before it enters the grounds. I also observed and noted the time when the liquid coffee first emerged. In the graphs below the thicker parts of the curves represent the same "portion" of the fluid flow, ranging from when the coffee first emerges to when the bottom water reservoir has only 35g of water remaining.
After all of this I spent a little bit of time trying to dial in the perfect moka pot cup. But I ultimately failed despite trying several strategies. I could get okay cups pretty easily and sometimes a very good cup, relatively speaking. Nothing fabulous seemed within reach. And I had plenty of sink shots that had that "moka tang" astringency that comes from too high a final temperature. Maybe I don't know what I'm doing. It doesn't matter as I have my Robot. Espresso is way easier than moka.