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.