If there was a simple answer you would never get a bad cappuccino, latte or espresso.. anywhere…. sadly this is not the case. It is easy to make a poor coffee from a good bean as many factors impact on the in-cup quality.
Here are three key points to start with. However other factors can greatly influence the the end product!
1. Freshly roasted & ground beans
Once exposed to air the roasted beans begin to oxidise (which is why all our coffee is packed in foil bags with a one way valve allowing the coffee to “breathe” whilst keeping it fresh). This oxidisation speeds up dramatically when the coffee is ground with ground coffee becoming stale within hours.
2. Setting the ground coffee coarseness to the machine in order to maximise the extraction
We would typically look to pour a single espresso shot in around 20-23 seconds. This can be dramatically affected by the setting of your grinder ( the best analogy I can think of is if you pour water into a bucket of pebbles the water easily finds its way to the bottom of the bucket – if you pour water into a bucket of sand the water is held within the sand). To optimise your grind setting you need a happy medium which allows for optimum extraction.
3.Temperature & pressure
Both these points are only adjustable through settings on your espresso machine and are likely to require a visit from your local technician.
Pressure: This is typically set within the machine. The optimal range to correctly extract the best taste from your beans is 8-10 bar. This should be displayed on the machine gauge whilst the pump is running (coffee is pouring from the group).
Temperature: Again this is adjustable within your machine. Older machines typically rely upon a heat exchanger to heat the group and therefore determine the pouring temperature with the boiler pressure switch, However the latest generation of traditional espresso machines have temperature control devices within the group to closely regulate the in-cup temperature. Ideally you would look to avoid temperatures exceeding 90 Celsius in order not to scorch the coffee during extraction and spoil the taste.