The acidic taste could be from over extraction. Too fine a grind. Also, coffee houses tend to brew heavier than most people do at home. In addition, the spray heads in newer commercial brewers disperse the water more effectively over the grounds so they get better extraction.
The next time you're in your favorite coffee house, ask if you can look at the grounds in the brew basket before they are emptied. Take a look at how coarse/fine the grounds are (should look like ground pepper) and the spray pattern on top of the grounds.
If you ask nicely and they are nice people, you might be able to take some of their coffee home ground so you can 1.) compare it to what you get out of your grinder and 2.) try it in your brewer to see if you get the same results.
I'd bet it is the grind or the extraction. It could also be the coffee - Central American washed coffees often have good acidity. It is a matter of taste. Again, to diagnose, start with the same coffee you get at your favorite coffee shop to see which of the 3 it is. (coffee, grind or extraction).