Brewing good coffee requires the right grind for the right coffee maker. Different coffee brewing techniques require different grinds. How coarse or fine coffee is ground is critically important to making good coffee! Coffee ground too fine will delay the brewing process and produce a bitter cup; conversely, coffee ground too coarse will speed up the brewing process and produce a watery, less robust beverage. You must also be aware that temperature and humidity will affect the espresso extraction process. A grind that works well on a cold, dry, day may also need to be adjusted when it's hot and humid.
The Rule of Thumb
The faster the brew method, the finer the grind. For example, use very finely ground coffee for espresso (which brews in seconds) and coarsely ground coffee for a French Press (the coffee needs to steep for 3 to 4 minutes).
Finer = Stronger.
A finer grind of the same amount of coffee will result in more extraction, hence a stronger coffee taste. If this tastes too bitter, you can use a coarser grind. at the same time, you might want to add more coffee to provide enough extraction for the strength you want.
If your coffee tastes weak, you may want to try grinding it a little finer.
If you detect bitterness, try grinding a bit more coarsely next time.
CoarseVery coarse particles, like kosher salt. Grind this way for a French Press.
French Press: The best way to control the time and temperature of the extraction is to use a French press. The French press offers unparalleled flavor due to perfect extraction time and delivery of the volatile oils that are often trapped in filters. A French press is also the least expensive brewer available. Unfortunately, the French press is not quite as convenient as a drip maker due to preparation time and cleaning time. The French press also loses heat faster than some other methods, but extraction at slightly varying temperatures will promote a more dynamic and complex cup of coffee.
Coarse grind is also used for a cold brewing method such as with Toddy filters to make iced coffee.
MediumA little coarser than the fine grind, it also looks and feels grittier. Use this grind for a manual drip brew method (a pour-over) or in an automatic drip brewer if you use a gold filter. (This slightly coarse grind will result in less sediment in your cup when using a gold filter.)
Medium particles and looks and feels like beach sand. This is the right grind for brewing in an automatic drip brewer with a flat bottom filter. A good choice but you may have to experiment a little with different grinds if you use an electric maker as that is the only way to control the extraction.
Drip brew is a method for brewing coffee which involves pouring water over coffee contained in a filter. Water seeps through the coffee, absorbing its oils and essences, solely under gravity then passes through the bottom of the filter. The used coffee grounds are retained in the filter with the liquid falling (dripping) into a collecting vessel such as a carafe or pot.
Paper filters are commonly used for drip brew all over the world. One benefit of paper filters is that the used grounds and the filter may be disposed of together, without a need to clean the filter. However, metal filters are also common, es- pecially in India or in home brewers. These are made of thin perforated metal sheets that restrain the grounds but allow the coffee to pass. Brewing with a paper filter produces clear, light-bodied coffee, which is free of sediments, but lacking in some of coffee's oils and essences, which are trapped in the paper filter.