Espresso: the pros vs. the home team

As I improve my espresso skills, I’ve learned that shortcomings are more obvious is straight espresso. Adding milk (including non-dairy milks and creamers) masks a lot. Every espresso I’ve tried, mine or baristas’, is bitter forward. In many that is all I can taste. At each new coffee house I’m now getting a single shot of espresso along with a latte. At the nearest Starbucks, bitter is all I taste. With Starbucks Espresso Roast at home now, there a bit of depth behind it. Before I started tamping hard, it was just bitter, i.e. under-extracted. At District Coffee here in Nashville, the straight shot had much more depth, other flavors, and a bit of acid. If I understand right, the barista over-extracted slightly. The beans, possibly the grind, and maybe the shot pull time are better than my attempts, but improvement is possible. So I’m doing better than that particular Starbucks barista and improvement is possible, but not as good as the District Coffee barista.