Dialing in espresso. What I have learnt from my first espresso training

As a newbie barista, it is such a pleasure that your workplace provides a coffee training to you. This blog is to record what I have learnt in the training.

What is Dialing in an Espresso?

Dialing in means to adjust the shot to be a desired espresso extraction, by changing the temperature, pressure, grind size and yield.

Extraction

When we talk about coffee, there is always a very important concept we need in our head: Extraction. Over-extraction and under extraction are also not good for an espresso. We always need to reach the middle of them, which is ideal extraction.

Under extraction

Under-extracted coffee means that the coffee particle haven't been extracted from the coffee bean. It tastes salty, sour, lacking complexity, lacking sweetness, lacking pleasant finish, unbalanced.

Over extraction

Over-extracted coffee means the coffee particles have been extracted too much from the coffee bean. It will bring the bitterness, burnt-ness, astringency, harsh acidity.

Ideal extraction

It should taste balanced, sweet, complex, long lasting, pleasant finish, as well as to have a rich mouthfeel.

Dialing in

To dialing in an espresso shot, we can change a lot of factors, such as grind dose, volume, extraction time, grind size. To simplify the whole process, this blog will only mention grind size and volume.

Volume

The higher the yield, the more water has been passed through the coffee – meaning a higher extraction level. 

By increasing the volume, the sweetness and biterness will increase while the sourness and body will decrease.

Grind

The finer the coffee grind is, the more sweetness, bitterness and body will be extracted, while the acidity of the coffee will decrease.