Blade-Type grinders are considered the most useless when it comes to coffee, as it virtually whacks the beans apart, making it almost impossible to achieve a uniform grind. In drip brewing methods, the fine powders will create bitterness and the larger chunks are essentially wasted, creating a watered-down taste. IF this is the method you have available to you, try grinding smaller amounts, shaking the grinder to expose all of the coffee beans to the blade. For drip brewing, count to 7 or 8 seconds, and for espresso, try 15 (one… Mississippi…two, etc).
Burr Grinders are the most efficient and best way to grind coffee beans as it creates the uniformity of particles needed to extract the best flavor qualities of the beans. The burr grinder uses two metal discs that rotate opposite each other to draw the beans between them and pulverize the heck out of them. Although the burr grinder is considerable more expensive than the blade-type, the cup quality and value will increase to compensate for the cost difference.
There are many methods of grinding depending on the purpose. For instance, in order for an espresso to capture the true essence of the coffee bean, it is necessary that as much surface are is made available for the water (which is moving past it at extreme velocity) to pick up all of the flavors. That is why a very fine, espresso grind is used. Coffee companies employ the use of a series of sieves to measure the degree of grind, by allowing the ground coffee to pass through from the most coarse mesh at the top, to the most restrictive at the bottom. The following illustrates to what degree of coarseness you should choose based on your intended purpose.
Medium Grind or Omnigrind: Are used in many slow-drip, percolated or French press coffees as the less fine coarseness of the grind requires more time for contact between the water and the coffee grounds to ensure adequate extraction. (Although Omni grind is often considered to be a degree appropriate for either slow-brewing or common brewing methods.)
Fine (Filter) Grind: Common for must filtered, drip brewed coffee brewers and most common degree found in commercial coffee grinders.
Turkish and Espresso Grind: These fine particles allow for rapid extraction from the hot waters that pass by them quickly and with greater pressure than other methods.
Hint: After grinding coffee from a commercial grinder, roll the grounds through your fingers to give yourself a benchmark quality to which you may compare future grinds.
Did you know? Some Italian Baristas will alter their ground on more humid days to a slightly coarser grind in order to maintain the ‘structure’ of the espresso?! Now that one might either impress people, or make them laugh!