Extraction

Extraction – what is it?

And how to get it right …or wrong

Extraction is simply the process by which flavour is extracted from a coffee bean using water, time and temperature.

But then it gets more complicated – of course!

In the final stage of processing them, coffee beans need to be roasted and, as we described in a previous blog, the length of time this is carried out for determines the strength, quality and flavour that results.

But that is not the end of the preparation before you get your cuppa!

This is where we get to extraction

To unlock the beans requires water and for the beans to be ground.  Beans are pretty robust and you won’t be able to extract much flavour if you leave them whole.

Now comes the technical bit! The end result in terms of flavour and strength depends on the type of bean, Arabica or Robusta, the length of time you boil it for and the temperature at which this is done.

You can only extract 28% of a coffee bean’s mass in water, so grinding is necessary to collect as much flavour as possible from the mass.

However, the trick in extracting the flavour is not to simply use more ground beans or heat them for longer. Too long and the taste is bitter, too short and the result will be salty, sour and with a taste that rapidly disappears.

So, extraction is dependent on the size of the ground grains, how long they were originally roasted for as beans, the temperature and length of time the grounds are heated for and to make matters even more complicated what type of coffee – from espresso to flat white you want as a result.

Things that can go wrong during extraction

Under-extraction occurs when you haven’t taken enough flavour out of the coffee grounds. This can lead to a sour or salty taste when a cup is brewed and a taste that quickly disappears after drinking.

Over-extraction occurs when you take too much of the soluble flavours out of the coffee and can lead to a bitter taste, excessive dryness, and a taste that can be described as lifeless.

A well extracted coffee has a finish that lingers for minutes. It is luscious, smooth and mouth filling. There should be a clarity of flavour and a balance to the acidity.

Perhaps now, you can understand the value of the most skilful baristas!