Grind Size Full Guide
How you make your coffee, directly impacts the time it takes to extract the flavours from your beans.
As such, it's important that the size of your ground beans compliments this method, in order to prevent extraction issues.
If your grounds are too coarse, you may not get enough flavour from your coffee, resulting in an unappetising brew. This 'under extraction' can be characterised by sour and acidic tasting coffee.
Alternatively, if your grounds are too fine, this can result in an overload of flavour from your coffee, resulting in an overpowering and unpleasant cup.
This 'over extraction' can be characterised by bold, bitter and even hollow tastes (with no notable coffee bean tastes).