I just got my first espresso machine, a Nuova Simonelli Oscar II.

When watching other people use the machine (on YouTube), I see some flushing the machine for about 2 seconds before every shot. Some don't.

What is the point of this operation?

1 Answer 1


Flushing helps clear any residue that might be left inside the machine or grinds stuck to the group screen before pulling your next shot. It also helps bring the group head up to temp before you lock the portafilter, so your first bit of hot water doesn't get cold as soon as it hits your puck.

  • I normally flush after a short to clear the residue left, rinsing the filter in the running water. I would have though that the group head was hot enough already, as the filter and filter holder are kept hot (touching under the spout for more then 2 sec, it gets too hot to touch). However, I notice that sometimes I get a hiss of steam if I flush the machine before a shot, sometimes I don't.
    – Pete
    Dec 15, 2020 at 12:05
  • 1
    Some machines have mechanisms to heat the group head, but nearly none put a thermostat on the group head. In addition, those models which heat the group head do so in a rather imprecise way, causing the group head temp to differ (often dramatically) from the water temp. Flushing helps align variables so you can get more consistent results.
    – R Mac
    Dec 16, 2020 at 0:27
  • That makes sense. Since my machine is a sort of budget machine, it would most probably be subject to those temperature variations.
    – Pete
    Dec 16, 2020 at 10:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.