In the past decade, people have been moving away from pre-ground coffee and grinding their own beans at home in order to have coffee that is as good as the coffee they buy from their local coffee shop. For new coffee connoisseurs this is a step in the right direction, but many people don’t get the best cup of coffee at home because they do not have the right grinder. There are two types of grinders, blade grinders and burr grinders.
Blade grinders work by using a blade to chop up the coffee beans. When you turn it on, the blades chop the beans finer and finer the longer you let it run. With blade grinders you have no control over the size of the particles, which often come out uneven. Grinding the beans for even a few seconds too long can ruin the grind, resulting in a poor-tasting cup of coffee.
Burr grinders work by crushing the beans in between a wheel and a stationary surface. The burr grinder has settings for specific types of grinds and there is no guess work involved in the process. The end result is coffee particles that are uniform. This is why a burr grinder is the best option to make sure your grind is precise.
Many people are unaware that the way coffee is ground affects the taste of the finished cup. Picture coffee grounds as a bunch of rocks. If you have a few rocks and you pour water over them, the water will easily flow through, but if you have lots of rocks that are packed together tightly, it’s more difficult for the water to get through.
For example, in a drip coffee maker, if the coffee is ground too coarsely, the water drips through too fast, resulting in a weak, watery-tasting cup of coffee. On the other hand, if the coffee is ground too finely, the water drips through too slowly and the coffee will end up tasting bitter. Coffee should be ground according to the way it will be brewed and grinds range from coarse to fine:
Coarse-French Press, vacuum pot, percolator
Medium-Electric drip coffee makers using flat bottom filters
Fine-Pour over methods, such as Chemex, Melitta, or any cone-shaped filter as well as moka pots.
Espresso-Espresso machines, Aeropress
Turkish-Turkish coffee made in an ibrik
For coffee purists, flavored coffee is a no-no, but if you do drink flavored coffee, it’s best to use a separate grinder because oils from flavored coffee stick to the mechanical parts of the grinder and it is impossible to remove them one hundred percent. These flavor oils will inevitably contaminate non-flavored coffee and distort the taste.
Sources: Personal experience in the specialty coffee industry.