peacecup wrote:If the coffee is really bitter the brew temperature is probably too high. I am currently using a backup machine of mine while my lever is under repair, and my wife has been complaining that the shots she's been pulling are really bitter.
That is because she does not know how to temperature surf - my shots are quite good.
Just do this: Get the machine ready, grind the shot and prepare the basket (but don't put the PF in the machine). Run 100 ml or so of water through the machine, then turn it off so it does not re-heat. Immediately lock in the PF turn the machine on and pull the shot.
This works for me every time, so give it a try.