A quality cup of coffee can depend on many factors, such as:
The time since the coffee beans were ground;
The time since the beans were roasted;
How clean the brewing equipment is;
The quality of the coffee bean being used;
The quality of the water being used.
Some Interesting Facts About Coffee
The quality of the coffee bean is the most important of these factors, if you are going to buy good coffee. The very best bean will taste bad if any one of the other listed characteristics are out of place. Not all coffee beans are equal, but the other points listed above will even the field.
A lesser coffee that has been freshly roasted and ground is many times better than coffee that has been roasted and ground then left to get stale - no matter how good it was when it was fresh.
A can of coffee found in the supermarket often contains large amounts of robusta, low quality Arabica beans and past crop (old) beans. To make matters worse, there is no way for the major coffee companies that roast and ship all over the country to get you truly fresh coffee.
Once you have coffee that has been freshly roasted and ground, good water and brewing equipment free of oil residues from the last brew and the quality of the coffee beans makes a huge difference.
How To Tell Coffee Quality
Please note that a coffee can bought in the supermarket often contains a blend of Arabica and robusta beans, while most coffee houses sell only Arabica beans. Arabica beans are normally rich in flavor - while robusta beans have more caffeine, less flavor and are cheaper to make.
There is an exception to every rule, and the exception here is that some very good espresso coffees will have small amounts of the highest quality robusta beans available on the market. This should not, however, be taken as a guarantee that a coffee house will have any better coffee than the diner down the street.
If any of the previously discussed items, such as cleanliness or freshness, are not in order then even the very best coffee can be made to taste bad.
When you buy coffee, whether it be in a coffee house or in a supermarket, you want to get 100% Arabica - except for espresso blends, which may be a combination of both. Whether good quality robusta can improve the flavor of espresso is up for debate.
For absolute freshness when buying in a coffee house, it is better to buy popular blends that move fast - while buying in a supermarket, vacuum packaged containers with an expiration date are your best bet although all canned coffee will be stale to some extent.
It should be noted that in order to be able to vacuum pack coffee, industrial coffee producers actually let the coffee sit for a while before it is packed. As soon as coffee is roasted it starts to release CO2, in a process called outgassing. This can actually help to protect the bean from going stale. Unfortunately for the people vacuum packing coffee or putting coffee in tins, this also will inflate the bags. This outgassing is the reason that you may very well see one-way valves on coffee bags. These valves allow the CO2 to escape, while keeping oxygen from entering the bag.
Chances are fairly high that you will not get truly fresh coffee in a supermarket. This is an absolute fact if it is pre-ground. In a coffee house, look for a shop that roasts in-house and ask what was roasted that day. If the person behind the counter does not know, ask to talk to someone who does know. If no one knows, simply go somewhere else.
Additionally, it should be noted that coffee is at its very best after a few hours rest. This is one of those places where an expert in the field of coffee can advise you. As a general rule of thumb, most coffees are improved with a rest time of about 12 to 24 hours. Some coffees, particularly those that are musty or earth coffees, actually mellow for the first two to three days - making a much longer rest better.
A final point to remember is that for best results, grind your own coffee. Buying fresh and then having it ground completely defeats the purpose. Ground coffee only lasts a few hours or one day at the very most.
Founder of Atitlan Network