Coffee and Espresso Machines Espresso machines make use of pressure to force water through finely ground and tamped coffee beans. They make a rich and tasty brew. Experts from the Good Housekeeping Institute recommend models that brew with the minimum pressure of 9 bars in order to achieve optimal extraction. https://www-coffeee-uk02441.elbloglibre.com/29722954/how-do-you-know-if-you-re-ready-to-coffee-machines-espresso