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The other day, I was watching an interview with an award-winning barista about how he prepared the award-winning cup of coffee.

When he was putting the coffee into the coffee basket, he was also using some kind of stamp, saying that the best pressure to apply is 22.5 kilograms when pressing onto the coffee.

Well, I was not doing anything like that until then. When I tried (because the award-winning barista is doing it), my espresso machine could not handle the amount of coffee I did put in there and instead of a coffee stream was producing coffee drips.

Now, to the question - my home espresso machine (Kenwood Kmix) should handle 16 bars of pressure, but is far away from professional device.

Should one apply pressure when filling coffee to espresso machine?

And if yes, how much?

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The process of compressing the coffee powder in a portafilter of an espresso machine before pulling the shot is called tamping. There is a lot of information available on the web explaining how it is done correctly, such as, e.g., here.

Tamping is an important part of making a good espresso shot, so yes, you should press the coffee in the portafilter.

The reason for compressing the coffee powder is to allow the pump to build up the pressure needed for brewing espresso correctly. If you don't tamp it, there is typically not enough resistance and the water rushes through the portafilter too quickly, resulting in underextraction of the coffee powder (and hence, suboptimal taste). Furthermore, a good tamp prevents channelling, where the water does not flow well-distributed through the coffee powder.

If the coffee drips too slowly when you tamp, a couple of things can be tried:

  • Tamp with less force. The correct pressure depends on the coffee powder, the diameter of the portafilter, etc. - so 22.5 kgs may simply not be right for your combination of machine and powder.
  • Grind your coffee less fine - this will lower the resistance.
  • Change your beans. In my experience, lighter roasts cause more resistance.

Options two and three are only listed for the sake of completeness - normally the tamper force is adapted to the other variables, and not the other way around. A good espresso making tutorial should give you a starting point on how to find the correct tamping force and grind coarseness level for your combination of beans and machine. Also, if you own an espresso machine and never heard of tamping, you may want to read one anyway.

  • this answer is unfortunately not correct. the tamping pressure is pretty fixed and not very important above a certain minimum. flow rate (and taste) is adjusted via grind and dose. a slow drip is either a too fine grind or a dose too high. – ths Dec 23 '18 at 16:31
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Tamping is of course one of the main steps of espresso brewing. Still, 22.5 kgf seems a bit extreme to me. I have used the same Kenwood k.mix machine, a few kgf would do a good espresso according to my experience. (Actually, you can't apply 22.5 kgf with the original plastic tamper, supplied with the machine, even if you want to.)

Furthermore, according to (Illy, 2005), vertical tamping force should be at most 20 kgf.


[1] Illy, R. Viani (eds.), Espresso coffee: the science of quality, 2nd edn. (Elsevier Academic Press, London, 2005).

  • I have an Espro spring loaded tamper. It's set to 30lbs. – Curt Apr 17 '16 at 17:12

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