Which element is NOT a basic component of espresso?

Espresso is a concentrated coffee beverage that is created through a specific brewing method involving key components. The primary elements used to make traditional espresso include water, coffee grounds, and pressure. Water is essential because it acts as the solvent that extracts flavors and solubles from the coffee grounds. The coffee grounds provide the source of flavor and aroma, which are essential for a rich espresso experience. Pressure is a critical factor as well; it forces hot water through the compacted coffee grounds, allowing for the quick extraction of oils and flavors that define espresso.

Milk, while a popular addition in many espresso-based drinks such as lattes and cappuccinos, is not a fundamental part of the espresso itself. It is used to create variations of drinks after the espresso has been prepared, rather than being a necessary component in the brewing of espresso. This distinction highlights that while milk enhances many coffees, it does not belong to the basic components required to make classic espresso.