There are too much information on coffee which can be confusing and complicated. Which often result in people picking coffee that does not match their expectations.
Here we will teach you the basics to what you should look out.
The darker the roast, the more bitter and less sour it gets. By statistics, most people prefer darker roast though medium roast should produce the widest spectrum of aromatic profiles. 
The darker the roast, the thicker is the body. Lighter roast coffee is more delicate as they have less CO2 that translates to a thinner crema and lighter body.
Coffee with Robusta tend to have a slightly more bitter, intense and persistent profile. They are also very thick in crema, making them very easy to extract consistently. They are the easiest coffee to deal with, they are the “classics” that most drinkers are accustom to.
It’s incorrect to have the perception that Robusta is always inferior. While it is true that most of the Robusta from many countries are of poor quality. Good Robusta can be found from selected estates found in many countries like India, Togo, etc. Robusta do have grades and the best Robusta does taste similar to the average Arabica and they can can also be treated to refine its qualities. What’s different in Robusta is it has an advantage in producing espressos with a thicker body and with greater consistency. They definitely do help in stabilizing the extraction, very forgiving and easy for any baristas to work with. Compare to Arabicas, Robusta is a hardy plant and is highly resilient to pests and disease, this means lesser herbicide and pesticide required for its cultivation.
Robusta can be refined to taste much better. Most of the Robustas used by Le Piantagioni or Arcaffe are fermented, processed with the washed method similar to how it’s done for their finest Arabicas. These methods tame the astringents and blossom the flavors. As buyers generally do not pay as much for Robustas, farmer who are motivated or skillful enough to nurture good Robusta crops are really rare.
Lighter roast coffee has a weaker body due to the lesser amount of oil and CO2 produced during the shorter roasting process. To achieve an equivalent amount of body comparable to a dark roast, you’ll have to use a larger amount of coffee used to equalize the yield if you are seeking a thicker body or crema. Baristas usually use at least 18g of coffee powder for a double shot when they use a light roast. However, we do recommend users to consider tasting the coffee with a regular dose of around 15g first, and test if it fits your palates. Despite its visually unattractive body with a very weak crema, we won’t be surprised that the clarity and balance may appeal better to your taste preference.
Lighter roast coffee can bring out the flavors of the coffee’s berry. Flowery and fruity profiles are better expressed. They are less bitter but tend to taste more acidic. So if you are a drinker who does not accept a tinge of sourness, you should go straight for a darker roast.
Medium roast coffee tend to have the largest bouquet of aromatic notes. This is known by science but do not be overly obsessed with such findings. As there’s a limitation to how much a person can taste. As a person ages, the ability to taste deteriorates. The thickness and body of a medium roast coffee may not be spectacular but they tend to stand well-balanced between acidity and bitterness.
It is always a mistake to judge your espresso visually, especially when you pay too much attention to the thickness of crema. Even veteran barista fall for this mistake as everyone expects espresso to have a crema as thick as possible. It is important that an espresso to have a layer of crema, but that does not mean that the thicker the crema the more successful is the result. The Italian traditional method of using sugar tests to test espressos were started at times when espressos were usually drunk by traditional standards using dark roasts and usually with Robustas. Lighter roasts used in the modern age may conjugate with different conditions. Blindly following such modality can often mislead and produce espressos that are great to look but not pleasant to drink. Leading to espresso with very extreme profiles that may taste awful.
For making a milky drink like a latte, and if you are using a lighter roast, you may need a double shot else the milk will most likely overwhelm the flavours of the coffee. For darker roasts, a single shot is usually enough. The size of the cup does matter, users will have to test with different conditions and discover their own preference of ratio. The standard size used in Europe for a cappuccino is around 6oz, 170ml. If your cup is 8oz or bigger, you may want to use a double shot espresso or a double shot ristretto.
For making espresso, the longer the extraction, or the more you extract, the higher chance of astringents are pulled into the drink. Sometimes some astringents in an overly acidic coffee can somehow counterbalance and perceive to be more palatable. As such, it really depends on the preference of the drinker. To get only the best essence of your coffee, it’s not a bad idea to end your extraction early. The Italians have a preference for drinking Ristrettos, which are half espressos. It’s not because they are tougher, is they are smarter to drink only the pleasant portion.
For brewing coffee by filter or infusion, we advise users to pay more attention to the temperature. Never use boiling water. Steeping for too long can pull out more astringents and produce a more intense coffee.
