Why is a good grinder so important?
First of all, because you can’t buy ground coffee from us (we only grind on demand)! You can find out why HERE.
But the grind size (how course or fine the coffee has been ground) is really very important. A barista will adjust the grind size of his/her grinder(s) every morning, or each time a new bean will be used. The grind size determines the extraction time of an espressomachine, and an ideal setting is necessary.
If the extraction time is too short, you will get underextraction and a sour flavour. Does it last too long, then you will get a bitter flavour because of the overextraction.
But not only barista’s adjust it. When using a Hario V60 slow brew set-up, the design of the dripper with its big hole offers almost no resistance. Only the filter paper provides a bit of resistance. So if you want to tweak your extraction time, you will have to be able to grind courser or finer. By doing this you can have a big influence the flavour yourself.
The difference between a manual or electrical grinder is obvious, but where do the pricing differences originate from? Without looking at the extra features (auto-dosing, zero-retention, etc) there is an important difference between cheaper and more expensive options regarding consistency.
A lot of ultra fine particles can clog the (porta)filter or can block the water for a too long period of time, whilst bigger particles (the so-called ‘boulders’) can cause underextraction (sour flavour – acidity). Ideally all coffee particles should be exposed to the water for the same amount of time, to not experience the sour and bitter effects that under- and overextraction do cause through inconsistent grinding.