MASL stands for metres above sea level. It tells you how high up the mountain your coffee was grown, and it's one of the best clues on the bag to how your coffee will taste.
So why does a number like 1,800 masl matter so much?
Slow coffee tastes better
The higher you go, the cooler it gets, especially at night. Cooler temperatures slow down how fast coffee cherries ripen.
That extra time is a good thing. The beans develop more sugars and more complex flavours, and they grow harder and denser. In the cup, that usually means more sweetness, brighter acidity and more going on.
Coffee grown lower down ripens faster. It tends to taste softer and rounder, with more chocolate and nut, and less fruit.
Higher isn't always better
Altitude isn't the whole story. Distance from the equator matters too.
Near the equator, it's hot all year, so coffee needs to grow high up to get those cool nights. That's why Kenyan and Colombian coffees are often grown at 1,600 metres or more.
Further from the equator, it's cooler at lower altitudes. Brazil's coffee regions sit much further south, so farms at 900 to 1,100 metres can produce excellent coffee, often with that classic chocolate and nut profile.
So a lower number doesn't mean a worse coffee. It usually means a different style.
Why some bags show a range
You'll often see something like 1,500–1,800 masl rather than one number. That's because many coffees come from more than one farm, or from a farm that stretches up a hillside. Lots from cooperatives and groups of smallholders cover a whole area, so the range shows where all those farms sit.
A single number usually means a single farm or estate, like Tinganga in Kenya at 1,830 metres.
