What does MASL mean on a coffee bag?

When you see 'MASL' on a bag of specialty coffee, you are looking at a vital piece of data regarding the coffee's origin. It is the industry-standard way of communicating altitude, which is one of the most important environmental factors influencing the final taste of your brew. Because coffee plants are sensitive to temperature, the elevation at which they grow dictates how fast the cherries ripen.

In general, the higher the MASL, the cooler the temperature. Cooler temperatures force the coffee plant to grow more slowly, which allows the coffee cherry to develop a more complex array of sugars and acids. When you see a high MASL number—typically anything above 1,200 or 1,500 meters—it is a signal that the coffee likely possesses the bright acidity, sweetness, and nuanced flavor that specialty coffee drinkers prize.

Conversely, lower MASL numbers often indicate coffee grown in warmer, lower-altitude regions. While these coffees can be delicious, they often have a different profile, frequently characterized by lower acidity and more straightforward, nutty, or chocolatey notes. By including the MASL on the label, roasters are providing you with a roadmap to the coffee's potential flavor profile before you even open the bag.

In practice, use the MASL as a guide for your preferences. If you find that you consistently enjoy bright, fruity, or floral coffees, look for bags with higher MASL numbers. If you prefer a more mellow, heavy-bodied, or traditional cup, you might find that coffees grown at lower elevations suit your palate better. It is a simple, three-letter acronym that tells a complex story about the mountain where your coffee was born.