Have you ever had a terrible coffee and wondered why? There’s a number of factors that determine the taste of coffee made through a cafe coffee machine and I’ll briefly cover them here.
The cafe coffee machine will control the temperature and the pressure, and can also influence the dose (filter basket size) and pour (filter basket holes)
Outside of the actual coffee machine the taste is affected by the grind, the dose (made by the operator), the coffee beans and the tamping pressure.
The temperature needs to be able to be set to the correct temperature for the coffee beans being used. Our preference for our own Diva coffee beans is 91 degrees Celsius. Other beans may work better at higher or lower temperatures. On a heat exchange machine the temperature is set from water passing through the steam boiler, and then getting stabilised in the group head. The group head has hot water circulating through it (officially called thermo-siphon) which sets the temperature of the group.
The pump inside a high quality cafe coffee machine will always be rotary, not vibration. A rotary pump will provide a constant pressure of around 9 bars giving you a better extraction.
Having either the temperature or the pressure incorrect will change the taste and flavour profile of your coffee, so make sure you invest in equipment that will get these things right.