First of all, premium-grade coffee beans are usually sold in two forms:
Mixed bean formula (Blends): the following different harvest seasons or more than two different producing areas of coffee beans mixed with each other.
Single producing area, unmixed single bean: single source coffee beans limited to a single harvest season, the English name is Single-origin Coffee or Varietal Coffee.
For those who bake coffee beans at home, single beans are the most popular because:
Accumulated knowledge: you can know where the coffee beans you are baking come from.
Taste exploration: individual coffee beans from different producing areas have different flavors.
High autonomy: when you are proficient in roasting coffee, you have a certain understanding of the flavor characteristics of various single beans, and you can mix the formula beans with personal style according to your preferences.
-- excerpt from the complete Book of self-Baking of Coffee by Kenneth Davis Kenneth Davids
