Technically, decaf is coffee whose caffeine has been stripped away in a decaffeination process. But if you want our opinion, decaf isn’t really coffee. It’s like zero-alcohol vodka. Pointless. The coffee equivalent of tequila shots, espresso is a tiny guy that packs a punch. It is brewed by forcing a small amount of near-boiling water under pressure through finely ground coffee beans. The process leads to espresso being thicker and having higher a concentration of caffeine than coffee brewed by other methods.