Espresso is a coffee brewing method that originated in Italy. A small amount of nearly boiling water is forced or “expressed” (hence, espresso) through finely-ground coffee beans under 9-10 bars of pressure. This pressurized brewing method is the most common way of making coffee in Southern Europe. I have many fond memories of having amazing espresso cups in France, Spain, Portugal, Italy, and Switzerland. The richness of this brewing method gave gravitas to every location I visited, whether it be a 5-star hotel or a roadside coffee stand. Espresso generally has a thicker viscosity than drip-grind, French press, cold-brew, or other brewing methods. This depth is due to the crema on top and the suspended and dissolved particulates that result from the pressurized brewing process. While espresso has more caffeine by volume than most other coffee processes, the total caffeine content is generally lower owing to the smaller overall volume.