- Edited
Good tamping practice says that you should level the pile of ground coffee in the basket before tamping, in order to get a homogenous puck.
It’s also said that tamping is only good up to a certain pressure, and beyond that, the coffee is not compressible any more, so tamping harder has no effect.
So today I tried something for grins. I ground coffee for my espresso, deliberately put it into the basket so that it was piled higher on one side. Then I tamped as hard as I could, resulting in an even puck. Here’s a sketch to show what I’m talking about.
Here’s my question. Given that the coffee is incompressible after a certain point, and the bed is even, why wouldn’t this provide a good cup of espresso? If the bed is even, tamping the previously uneven pile of coffee must have moved coffee particles from the higher side to the lower side. And since I used enough pressure with my tamp, the coffee must be packed evenly.
I thought one possibility is that I was wrong about the incompressibility issue, and that it was possible to have a situation where the bed was even after the tamp, but the coffee was still unevenly distributed. If this was the case, then there should be less densely packed areas of the puck. But probing around with a toothpick (aka my excellent WDT tool 😆) didn’t find any soft spots.
The only thing I didn’t do was to make espresso with this puck. I scrambled the puck with my toothpick, leveled the ground coffee, and tamped. My espresso was yummy. But I probably will pull a shot while tamping a deliberately uneven bed soon to see what happens. In the meantime, I was wondering what you all might have to say.