Making coffee
(found on) http://espresso-for-geeks.kalaf.net/guide/
The basic way to make coffee is to just apply water (usually hot) to coffee grounds then filter but there are different ways to do this to end up with different types of drinks. Espresso machines force hot water under pressure through finely ground coffee which makes a much smaller more concentrated drink with less water compared to regular drip coffee which just uses gravity to feed water through coffee grounds.