mazur wrote:I have been doing much reading and have read numerous times about how single origin is not usually good for espresso and a blend or espresso specific roast is recommended.
At best, this is outdated advice. At worst, it's just plain wrong. As you yourself noted, you really enjoyed single-origin espressos from your local shops/roasters: Cartel, Peixoto, and Royal. Many of the high-end roasters recommended on this site offer exceptional single-origin espressos that you may like a lot. I haven't counted, but I'm sure that many espresso drinkers on HB prefer SOs to blends.
There's a grain of truth in the advice in that some single-origin coffees don't work particularly well as espresso by themselves, but do work well as part of a blend with other coffees. There are certainly some very good, and even exceptional blends available from the roasters mentioned above, so keep looking and trying.
That said, many blends have been created to appeal to those who prefer "comfort" coffee -- often a somewhat mild, sweet and chocolaty experience. To get there, the roaster may blend single-origin coffees so as to mute the more forward or tart flavors and bring out the mellow tones. Some roasters will also roast their blends darker to reduce acidity. This can be a tasty drink, almost a confection, especially when sugar is added. This is also characteristic of the espresso you get in Italy, which can be a very pleasant but not particularly complex drink
You may find such blends boring or single-dimensional when compared with a complex bright single-origin blueberry-bomb natural from Ethiopia.