Ok, so we have flushed, over 5 tank loads, and the coffee is still bitter, back of mouth acrid taste (sorry, my descriptions aren't too accurate)
I am wondering whether there are two issues 1. The initial problem with bad taste; 2. Chemical residues from too much descaler.
I was descaling once every three to four months, with a descaler bought from the company I bought the machine from. It may be too strong, and we may have added chemical reside to our problem. But I think we have rinsed the machine enough!
The water tastes fine so I made a shot hoping to have a gorgeous coffee.
but no, bad pour, smells thin, looks too dark and the crema too blonde.
the shots pour ok, in a thin stream over 20 secs, the biscuit is a bit too damp, tastes terrible.
the shots are around 78degrees, don't seem to have got hotter or colder.
I did test the grinds and they seem consistent, feel like salt grounds. a month ago I did buy preground coffee to check, but it didn't seem to make any difference to the flavour.
any way I can check whether it is a thermostat or pressure issue?