There's actually no such thing as an espresso bean. Any coffee can be brewed as espresso, but there are coffee blends specifically formulated for espresso that taste best as espresso drinks.
That said, although some cafes have started offering single-origin espresso shots, by and large espresso is made with blends specifically designed for espresso. What matters most, from the point of view of the barista, is how the beans are ground. While drip coffee is best when the beans are a medium grind (about the size of sea salt), for espresso, the beans need to be finely ground and the consistency of the grind is essential.
Because of the pressure required, espresso requires specialized equipment. Starting out, you need an espresso machine that can get up to pressure and produce consistent hot water, as well as a grinder that's going to produce consistent finely ground coffee. In the espresso world, our magic word is consistency. A great burr grinder is going to be the most consistent source of even finely ground coffee. Making a great shot of espresso requires an initial commitment, but once you put in the time and the practice, it's immensely rewarding to pour your first great-tasting shot.
While you can't make a bona fide espresso without pressure from a machine, you can get close(ish) to the real deal with one of these methods:
Making espresso with a French press basically means making less coffee. Here's what you do: Boil one cup of water. While you wait for the water to heat up, add two tablespoons of freshly, finely ground coffee to your French press. Add a bit of the boiling water to the French press and stir briefly. Wait four minutes, then slowly push down the plunger, pausing every few seconds. Note that it'll be slightly challenging to push the plunger down due to the grind size.
The same goes for an AeroPress; using your normal brew method for the AeroPress, prepare less coffee using a fine grind. If able, heat your water in a kettle to 205 to 210 degrees Fahrenheit (the optimal temperature for espresso in an AeroPress, as well as a French press).
If you’ve ever stared slack-jawed at the coffee shop menu wondering what the difference was between all the espresso drinks, you're in good company! Here's an overview of the different types of espresso drinks:
Blonde espresso, popularized by Starbucks, is simply an espresso made with light roast coffee as opposed to a traditional espresso, which uses medium or dark beans.
Some baking recipes call for espresso powder, which is made from darkly roasted, finely-ground coffee beans. You can buy espresso powder at the supermarket or make it on your own at home. It's not meant to be used to make an actual espresso, however.