It would seem that the taste of the coffee will vary depending on how long I run the machine for. Is that correct? I'm using pre-ground coffee at the moment as I have a roastery right near my work
Probably need to check they are giving you an espresso grind - which can be a lot finer than filter ? and buy jit.
gram accurate kitchen scales should be good to measure the ~14g and can pre-measure what the level point will be in your favourite cups for the ~50ml level, which should be ~20s.
- cant' find an earlier post of mine that has a good table of mass/volume/time, from coffeeforums I thought.
- as per many comments in the thread, I too never mess with single shots or single pf, too unpredictable and not enough volume !
edit
• Necessary portion of ground coffee 7 g ± 0,5
• Exit temperature of water from the unit 88°C ± 2°C
• Temperature of the drink in the cup 67°C ± 3°C
• Entry water pressure 9 bar ± 1
• Percolation time 25 seconds ± 2,5 seconds
• Viscosity at 45°C > 1,5 mPa s
• Total fat > 2 mg/ml
• Caffeine < 100 mg/cup
• Millilitres in the cup (including foam) 25 ml ± 2,5
https://www.home-barista.com/knockbox/what-is-proper-volume-of-single-shot-of-espresso-t6036.html