Bar pressure is the number one factor that sets espresso machines and coffee makers apart. Coffee makers use gravity and time to extract flavors and caffeine. They can take up to several minutes to brew.  Espresso makers are so quick and rich because of bar pressure. Technically, the ideal sweet spot for brewing the best espresso is at around 9 bars of pressure. So while you see plenty of budget espresso machines boast 15 and 19 bars of pressure, these added bars may be to compensate for lower quality components that lead to pressure loss in the brewing process.