Coffee machines are devices designed to brew coffee by heating water and passing it through ground coffee. They come in various types, including drip coffee makers, espresso machines, and single-serve pod machines. Each type has its own brewing method, but all aim to extract flavors from coffee grounds to create a beverage. Most coffee machines have a water reservoir, a heating element, and a filter system. Some models offer programmable features, allowing users to set brewing times or adjust the strength of the coffee. Popular brands include Keurig, Nespresso, and Cuisinart, each offering unique designs and functionalities.