Jewel Coffee

I had three different coffee here. I had a Ethiopia Sidamo as an espresso, Brazil Cerado (i think) as a machiatto and tanzania ___________ via chemex. I didn't notice the other coffee names because i was too focus on the Ethiopia Sidamo.A sidamo as always never fail to satisfy my tastebuds.
Something thats not nice, the next cup of brazil as a machiatto is too acidic, almost made me puke and with the additional flat tasting (it tasted stale) Tanzania, my stomach turned queasy almost immediately.So did i finish them? Ask me and i tell you.
Well..It's just probably because I haven't had breakfast and that was already my third cup of coffee of the day (i was on coffee hunt mode).

I still want that perfect tanzania brew because i swear i've tasted clear blackcurrant notes a year back. No secret, i bought it from starbucks (everyone says SB roast their coffee too dark).

So my question is. What is the ideal roast for Tanzania.Slighly darker then how a Ethiopia sidamo should be? Nowadays, everyone is roasting till medium roast profiles without understanding that different beans has different profiles...! Their goal is to achieve "oil-free dry surface" rather then achieving the "sweet spot". I think the Brazil and Tanzania should be roasted a notch or two darker.I'm no expert but you are..