Coffee Appreciation

I'd say the ACS is stale by now, hence no crema and rapid blonding.

I would say the rapid blonding with your fresher Illy may be due to you not tamping the coffee hard enough?

I use a plastic (!) tamper and manage to get crema most of the time without much blonding.

As for dosage, it is for taste really. Too much and you'll know about it (sweats and etc) too little and there is no 'kick'

Keep trying!

To be honest, I've been using Illy for the past 4 or 5 years and I've never had perfect results - and I've tried all kinds of stuff in terms of technique: really hard tamping, filling the portafilter as much as I can etc etc. It tends to taste stale even when you've opened a fresh tin.

Makes me wonder why I've persisted so long...