When making espresso with your espresso machine, it is very important that the ground coffee is well packed in the filter basket. If the ground is not properly compacted, the water will flow through the coffee to quickly and create thin and bitter cup of espresso. This is much the same principle as when grinding espresso.
The Espresso Tamper
The tool for the job is called an espresso tamper, and the process is called tampering. A correct tamping makes the water flow through the coffee evenly so that no part of it is overextracted during brewing. The tamper is usually made of metal and can have a flat or a rounded bottom. Cheep ones coming with your espresso machine may also be made of plastic.
Choosing the right tamper is not rocket science, however it is important that the tamper has the right dimensions for the filter basket of your espresso maker.
If the tamper is too small, this will result in an unevenly packet ground with higher density in the middle, and thus the water flowing past in near the edges of the basket. Also, getting a tamper that gives you a good grip will also make things easier.
Good tamping with the right technique
When tamping your espresso ground, follow these easy steps.
1) Fill the filter basket with ground coffee. If you are making a double espresso, start by only putting half the dose in the filter.
2) Knock the filter basket lightly against the counter to make the coffee even out in the filter basket.
3) Grab the tamper and press straight down against the coffee. You should press quite hard, so it helps to put the filter basket down on the counter. Finish by twisting the tamper a bit using the power of your wrist.
4) Check the basket for any loose coffee near the walls, you will find at least some. Knock the tamper lightly against the counter again, and repeat the tamping once again.
5) If you were making a double espresso, add the rest of the coffee and repeat step 1 to 4 above.
When you have finished your tamping exercise, make sure that the coffee is evenly spread in the filter basket. If not, start over again until you get it right.
Espresso tamping is not hard when you know how, but depending on the pressure and quality of your machine, as well the ground you are currently using, the pressure you need to apply with the tamper may vary. Practise a few times until you learn the technique and the right pressure for your particular machine.