Coffee is as dynamic and diverse as culture itself. Considered a hallucinogen in it's early discovery, being banned by the Catholic church and then later approved, being central to the French revolution. Coffee has taken some serious twists and turns but has always remained central to humanity. Over one billion people are involved directly with coffee production or trade in the world. It accounts for the most traded commodity along with oil in the world.
Are there any timeless rules or values, about coffee itself?
There are so many ways to make coffee. From coffee cherry (fruit) tea to the Vietnamese roasters including flavours in the roasting procedure, and drink it with sweetened condensed milk. The busy people of the European world opt for automatic machines while the baristas in the specialty coffee movement in Melbourne only want to make espressos and drip filter coffee according to strict recipes.
Here are a few timeless coffee "rules":
1) Green coffee contains none of the flavours of roasted coffee. Heat transfer creates the sugars and carbohydrates that we love in coffee. Unlike cocoa which is somewhat tasty green while bitter coffee is nothing lie the roasted beans we consume.
2) Roasting is usually between first and second crack. While there are many ways to roast coffee ( air, stove, oven, barrel) you will always achieve sweetness at around 10-15 minutes and 200 degrees. Reading: http://www.scottrao.com/
3) Extraction - espresso: You will usually find that espresso extracts best at around 80-90 degrees Celsius, and that the longer you brew espresso the weaker it gets. Also a ration of 1 part coffee to 3 parts water is the norm.
4) Extraction - filter: You can brew filter coffee from cold water to boiling water. You will usually use a ratio of 1 part coffee to at least 5 or even up to 20 parts water. Also the longer you brew filter coffee the strong it gets, usually.
5) Finally taste is as diverse as any of these factors. People like burned coffee. Some people like robusta. You cannot prescribe what people will like but we can always give them our best.