Most espresso machines are set by the manufacturer to brew at between 8 and 9 bars of pressure. While this is a pressure that works well, it doesn’t mean it’s the best pressure. Some coffees extract best at higher levels of pressures, others extract best at lower levels of pressure. Some espresso machines, such as the spring lever Elektra Micro Casa a Leva will peak at about 6 bars of pressure. Other machines like pressure profiling machines will start at a lower level of pressure and build up to a higher level of pressure and then drop back to lower levels of pressure at the end of extraction. Many machines allow the consumer to adjust the brew pump pressure up or down, but it can sometimes be difficult to adjust without taking the side panels off the machine.
