Arabica is considered the more premium of the two and commands higher prices. It is more flavorful which is the result of the precise growing conditions that are required. Arabica plants need lots of moisture, sunlight and rich soil, which are found at higher elevations. In fact, the higher the altitude, the more expensive the coffee.
Robusta beans have less flavor and body than Arabica beans but have more caffeine and are hardier. They can grow in many conditions as they are more tolerant of cold and can be grown in a wider range of altitudes than the Arabica. They also produce beans quicker than Arabica plants and can be harvested in 2-3 years after being planted versus 4-5 years. For this reason, Robusta beans are more economical for coffee farmers to produce.
What does this mean to you? First, the coffee you find in your local supermarket is more likely to be Robusta as it can be ground and canned or vacuum-sealed without losing much taste. It is also what you find in instant coffee as well.
If you go to Starbucks, Peets or another coffeehouse for your coffee then it means that you will pay a premium for anything that is 100% Arabica beans. You will pay a little less for those blends that are mostly Arabica with a little Robusta added in. That is not necessarily a bad thing to have some Robusta added to your premium coffee. In fact, it is said that Robusta beans help to form a better crema in espresso.
The biggest things to remember are that if you want more caffeine than look for Robusta and if you want a flavorful coffee than you want Arabica. If neither matters to you then just make sure you are not being charged a premium for Robusta coffee and be suspicious if someone is offering you what they say is Arabica but are charging you a Robusta price.
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