Salty in espresso means underextracted coffee. Many factors play there: such as grind size, pull time, tamping method, and water temp. A good espresso taste balance, you got the acidity and bitterness in sync, and give you sweet creamy taste.

Note: pourover methods usually more forgiving and give you better taste. I suggest you try those methods for your black coffee.

I'm using clever dripper for my manual brew, enjoying coffee bean from West Java, Indonesia. Still pulling a double shot once awhile, just when I need a (stronger) quick fix.

Do you mean coffee bean from the US? I live in Indonesia, and I do have a lot of recommendations. But I don't know whether they can ship it to US.

Manual brew? V60 and flat bottom if at home (use them alternately), Aeropress if on the road.

How can we rotate the picture? I posted it from Jerboa...

None that I know, at least not in this instance. Maybe other instances? Or you can make one if you like.

Yes, Mugen is fantastic brewer. It's a "low by-pass" type, producing smooth brew. And the pour can be continuous. Here's a picture of it.

I'm using 60g/L, the best ratio in my opinion. I grind it using Timemore C2 and brew it using Hario Switch.