The capacity and size of a coffee machine is the amount of water storage and the fills. The capacity of the coffee machine is vital especially if you are using the coffee machine for commercial purposes and want to make many espressos in quick succession. Get to know how many cups you can make at a time without having to reach behind after a few minutes to refill the water tank. Some machines can make up to twelve cups at once. Also, watch out for machines that don't distribute coffee evenly between cups.