Coffee school

Although coffee is one of the most heavily consumed drinks on the earth, many people know very little about the factors that can determine the difference between a great cup of coffee and a mediocre one. Coffee is the largest traded commodity throughout the world; yes, even greater than oil.
Coffee can grow anywhere between the Tropic of Cancer to the north and the Tropic of Capricorn below the equator. Although coffee is grown from sea level up to 7,000 feet, the higher quality grades are grown at higher altitude ranges.

Coffee is divided into two categories, Arabica & Robusta. Arabica coffee is the superior species from the coffee lover's point of view. Arabica beans are the bean of choice in "gourmet" or "specialty coffees". Arabica coffee beans produce the rich flavor and body found in a good cup of coffee. Robusta lacks this flavor and body.
There are several differences between Robusta and Arabica coffee beans. Arabica coffee is difficult to grow. It is more prone to disease, requires more hand cultivation, and yields smaller harvests per acre. The Robusta species is a hardy, high-yielding plant resistant to the numerous pests which afflict coffee.
Robusta coffees have higher caffeine content than Arabica; up to twice as much. Robusta is used in instant coffees and in most blends found on grocery store shelves. Arabica beans are much more expensive, which is why the large coffee companies use predominantly Robusta coffee.
Sometimes coffee companies will blend a small amount of coffee Arabica with a larger portion of Robusta. Coffee regulations in the United States only require manufacturers to specify that they are selling 100% coffee. This allows coffee manufacturers to blend 10% of an expensive type of coffee with a much cheaper grade and advertise is it as a specialty blend of coffee. This can be avoided by ensuring that when you buy coffee that they specify that it is 100% from the country and crop advertised.
Roasting also affects taste, as does the length of time from roasting to consumption. Unlike fine wine, roasted coffee does not improve with age. With modern packaging methods the window of optimum taste after roasting is extended from 2-5 days for up to several weeks; however, grocery store coffee can be on the shelf up to six months before reaching the consumer. Coffee is best stored in a cool, dark place with constant humidity- keep it out of the fridge.
African, Malaysian, Central American, and South American coffee beans all have distinct flavor characteristics and the darkness of the roast will yield different characteristics. The roast that is characterized as "Italian", the darkest of the roasts, (Starbucks) will cover a multitude of flavor flaws.
Other important factors include:
the grinding of the bean (for the love of all that is holy, please don't drink coffee that was ground up months ago, it is a travesty!), coffee should be as fine as possible without turning it to powder
for American-style coffee, the filter. Paper filters are the most common but absorb many of the oils that contain the flavor of the coffee. Metal filters are often coated to prevent a metallic flavor and have the advantage of being permanant. Cloth filter are a good flavor alternative though they require rinsing (clear water only) and have a life span of about 3 months.
Brewing at the proper temperature; starting with clean, fresh water (alkalines are not friendly with coffee), and keeping your coffee making equipment clean will all contribute to a better cup as well.
NEVER allow coffee to boil, the coffee gods will weep.
And a finally, the best for last...
espresso...good espresso is rich, heavy-bodied, and almost syrupy; furthermore, it has the characteristic bittersweet bite of dark-roast coffee. The sharp flavor and heavy body make it an ideal coffee to be drunk with milk and sugar, milk dilutes and mellows the strong, sharp coffee.
Espresso is several things at once. It is a unique method of brewing in which hot water is forced under pressure through tightly packed coffee, a cup at a time. It is a roast of coffee, darker brown than the normal American roast but not quite black. In a larger sense, it is an entire approach to coffee cuisine, involving not only roast and brewing method, but grind and grinder, and a technique of heating milk. In the largest sense of all, it is an atmosphere or mystique: The espresso brewing machine is the spiritual heart and esthetic centerpiece of the European-style cafe.

There are two basic requirements for making good espresso. First, you need to grind the coffee just fine enough, and tamp it down in the filter basket just hard enough, so that the barrier of ground coffee resists the pressure of the hot water sufficiently to produce a slow dribble of dark, rich liquid. Second, you need to stop the dribble at just the right moment, before the oils in the coffee are exhausted and the brew becomes bitter and thin.

Alright, I will stop now. (breathing deeply)
Just imagine, this is only on the topic of coffee,
don't get me started on politics, religion,
or the freaking-27-straight-days-of-rain weather!