Coffee and Espresso Machines Espresso machines make use of pressure in order to push water into finely roasted and tamped beans. They make a rich, tasty brew. Experts from the Good Housekeeping Institute recommend models that brew at a minimum pressure of 9 bars in order to achieve optimal extraction. https://www.coffeee.uk/products/smeg-146875-coffee-machine-adjustable-temperature-milk-frother