These guidelines are a recommendation for the initial calibration of your grinder when trying out and adjusting to a new coffee.
You will need the following:
- a scale that reads to 0.1 grams
- fresh coffee
- espresso grinder
- espresso machine with a double basket
Steps to calibrate the grinder:
- Set your grinder so that when you are pinching the grinds between your fingers you feel a very fine granularity, just a little coarser than powdered sugar.
- Load your double basket with 12 grams of coffee.
- Adjust the grind until you get a shot that weighs 20 to 25 grams in 30 seconds. (when timing the shot count the dwell time, the time between turning on the pump and seeing the first drop, at 50%)
- This is your finest grind setting, suitable for light roasts, very acidic coffees, or otherwise very powerful tasting coffees
- Repeat the procedure using a dose of 16 grams and a coarser grind. The setting that gets you 20 to 25 grams in 30 seconds as before will be your coarsest grind setting, to be used for very bland tasting coffees
Keep in mind that on some machines, the calibration can be way off. And this here are recommendations and a good starting point. But don't hesitate to make changes once you have become confident doing the tasting and making the dosing changes so that you get the cup that suits your personal preference.