temperature is very important to espresso.
some palates finer than mine vary the extraction temp within a 5 degree range : 200 - 205 based on the green bean blend
dry processed vs wet processed
Ive tried this and I can't taste the difference so all mine are done at about 200 f I have a PID Alexia for the temp is very finely comtrolled
by the machine not me.
time from first ' drip' to end iof the extraction s also very important too fast : under extraction too slow over extraction.
If you read various coffee forums etc this degree of detail might seem
dis-ingenous and for im sure a lot of HuffPuff's it is.
but most of it is not if you've event the time working this our for yourself.
I have worked to the point that any more Fine Control would escape my palate.
one important point : your home grinder has to match the ' level of precision ' of your espresso machine.
or you buy a cheaper machine as thou are loosing the potential benefit of the more expensive machine
its a series that ' adds up ' A + B + C + D = espresso. you have to look at the lowest common denomitaton
as you cannot get great espresso out of DunkunDonuts coffee beans with
if you made DD's ' coffee' at home w their beans you would get DD's coffee ' at home '
the grinder above has one benefit : you can have two different espresso blends of beans on hand at the same time !
green beans -> roasting -> grinding -> extraction . as well as the cup. why would you can't to drink The Real Deal out of plastic ?
as @weinoo has suggested :
don't forget your water quality !