This coffee dosing tool is based on the Breville Razor. The principle is that dosing coffee for an espresso portafilter should be done volumetrically, aiming to fill in the available portafilter basket space, without overdosing or underdosing (unless intentionally done).

The usage is simple:

1. Grind coffee, and tamp into the portafilter basket
2. Place this dosing tool vertically in the basket, and observe whether it digs into the coffee puck, floats over it, or is at the same height.

If the tool doesn't reach the coffee puck, then it's underdosed. If the tool digs into the coffee puck, then it's overdosed. Else it's just right!

If you regularly use coffee puck screens, you can generate (or use) a variation of the tool that takes their thickness into account, or you can simply use the regular one, looking at whether it touches or not the screen.

The tool is designed and tested with the Gaggia Classic (Pro) coffee machine, based on the gasket thickness (8mm or 8.5mm), and the fact that the shower screen has a protruding screw.

You can edit the tool design with this OnShape workspace!