I’m in exactly the same boat at the moment. Apart from the hardware, the ‘software’ is also, or even more important. My first cups were awful, like bitter or sour aftertaste for more than an hour. My grinder lacks a clear indication (Mignon) and I did start at a completely wrong point. And before you know it, you start tweaking lots of parameters simultaneously. For me, the key was to “stay calm and keep grinding” and reduce complexity. 😎
What I did is buying lots of reasonable but not very expensive medium dark roasted beans. Dail-in the grinder so that you get a cup with 1:2 ratio (weight of beans: weight of espresso) within about 25 to 35 seconds. In my case, sometimes almost drinkable, most of the time entirely not. But I reasoned that this is a good starting point to optimize.
Next point was optimizing the temperature. Because my puck preparation skills were bad, this took some cups. But this way I got away with the sourness.
On my machine (Lelit Elizabeth), the pressure was at the high end, so I reduced it to 9 bar. I think this improved the harshness but could also be coincidence.
I did set-up a pre-infusion of 5 seconds, which again reduced harshness a bit. Don’t know if your machine supports this.
At this time, 1 out of 5 or so cups were drinkable.
Next step, improve puck preparation. Got a cheap Wdt tool with thin needles, a funnel, but skipped the self levelling tamper. I think the craft of coffee making prevails using too many automatic tools. Better practice a bit. 🙃
After about 2 weeks, I am now at the point that I’m able to consistently make quite drinkable espresso’s. Still the same base settings and same beans to keep the situation stable. Already better than the nespresso stuff.
Now is the time to try some medium roasted beans and tweak the base settings accordingly.
I found out that espresso is quite different from nespresso. Think a factor 10 stronger taste, especially when you make the mistakes that are unavoidable at start. But at some point it is going to give the rewards you want. My biggest challenge was to get the grinder in a somewhat reasonable setting, but as far as I know the Niche Zero has a better fineness setting indication.
Good luck!
