On the corner of 18th and San Carlos Streets, espresso-only Linea is practically at the Mission's central coordinates, so yeah, the beans are going to have a serious pedigree akin to those people who are always like, "I'm a fourteenth-generation San Franciscan." And Linea's website is currently just a web page attesting to this fact. (But where else are you going to get a shot from a judge of the World Barista Championship?)
See Also: Linea Caffe: A Coffee Shop A-Team
Tiny though it is, Linea also houses Lt. Waffle, which serves five varieties of sweet and savory, including egg soufflé with chevre and a yeasted waffle topped with coconut jam, gianduja, and macadamia. Somehow, the gorgeous buckwheat waffle with crème fraîche, salmon roe and cucumber felt lacking, managing to be dry in spite of all that lusciousness. It just didn't satisfy the way a bagel with lox and a schmear does. (Full disclosure: I didn't judge the World Bagel Championship, but I grew up on Long Island.) It's not a perfect apples-to-apples comparison, but on texture alone, Lt. Waffle did not measure up to the ethereal b. street. You can also order one of several salads, but the connection with truly excellent espresso is less obvious.
Noting the Heath Ceramics cups and saucers -- and A+ on that front, Linea -- the blog Dear Coffee, I Love You. also said it's good for "standing around talking." Indeed. It has zero seats, and that big open window -- including the ledge I ate off of while standing on the sidewalk -- is going to look a lot less inviting in about three weeks. Which is too bad because it's actually a very handsome cuboid space, with friendly baristas. It would be a real shame to fill it with elbows and texting and all that lot, when this place inevitably takes off.
Lt. Waffle (inside Linea Caffe), 3417 18th St.