As green coffee ages, its flavor characteristics change. If it is stored in cool darkness it may change very little over the course of years, at most losing some acidity. However, coffees stored in warehouses located in hot, humid tropical port cities can change in flavor dramatically and rapidly.
Coffee delivered for roasting soon after harvest and processing is called new crop. Coffee that has been held in warehouses for a period before delivery is called old crop. The differences between new and old crop may be minor. Sometimes the old crop is better because it displays more depth and less immature grassiness. In other cases new crop may be better because it is brighter and fresher tasting, whereas old crop may taste dull or woody. At times roasters combine old and new crop of the same coffee, aiming at a more complete version of the same flavor profile.
Aged or vintage coffees, however, are a different matter. Traditionally aged coffees, which are rare, may have been held in warehouses for anywhere from three to ten years, and can be superb: sweet, full almost to a fault, syrupy but clean-tasting.
However, a kind of accelerated aging is now performed in Indonesia, wherein the beans are deliberately exposed to moist air, much like India’s Monsooned Malabar. These aged coffees lose acidity and gain body, but they also gain a kind of hard pungency which I do not care for, but which some coffee drinkers find attractive.
If an aged coffee originates in Latin America, most likely it has been aged in the traditional way. In fact, it may have been inadvertently aged. An importer or grower may have found he had too much coffee to sell, stored it, and trotted it out some years later as a special delicacy. As conceptually sloppy as this practice sounds, it often produces the best aged coffees, with a sweet heaviness unmarred by hard tastes.
Today, however, most aged coffees come from Sumatra and Sulawesi, and most are aged quickly, by deliberate exposure to humid air in port cities. Try one. I am not a fan, but you may be.
