A good quality grinder is an absolute must for those who enjoy the aroma and taste of freshly brewed coffee. It is the second most important accessory one can buy after a coffee scale, in terms of taste impact in the brewed cup.
Why do we need to buy a grinder if we can simply buy pre grind coffee and keep at home?
The aim of grinding the beans before brewing a cup is to extract maximum taste and aroma from the coffee beans.
Grinding the coffee beans exposes more of it to the air, which means that the coffee will go stale more quickly, (noticeable taste differences in as soon as 15 minutes!) so it should ideally only be ground just before brewing cup.
Why can’t we just use a blade grinder from the kitchen to grind coffee beans?
Burr grinders have two cutting discs, called burrs, facing each other and you can adjust the distance between them to change the size of the grounds of coffee produced. Because the coffee grounds can’t escape until they have been cut down to the size of the gap between the burrs, the resulting grounds are very even in size. Burr grinders produce even pieces and an adjustable range of sizes, so they are ideal for brewing great coffee.
One can grind coffee beans in a blade grinder too but you are basically playing Fruit Ninja with the coffee beans in it - resulting in everything from very fine coffee grinds to very large chunks and everything in between.
These uneven coffee particle sizes result in an uneven tasting cup which is often extremely bitter too due to the coffee fines.