Mineral flavors in East African coffees

I have tasted a great deal of coffees from the collection of countries surrounding Lake Victoria in East Africa. Ugandan, Rwandan, and Burundian coffees tend to share a common flavor characteristic which I call “minerality.” While this term is common in the world of fine wine, it is less commonly used, if hardly ever, to describe coffee characteristics. This flavor is not the same as “earthy,” which one might find in lower-quality coffees or poorly-processed Sumatran lots, rather minerality is a unique flavor tone that is both stimulating and mysterious. To be honest there’s nothing quite like it, and for some reason these few countries seem to carry this flavor in greater capacities than nearby Ethiopia or Kenya. Some people would describe minerality as being akin to “smelling wet stones” or “tasting a raw-ceramic,” either way, this isn’t an easy flavor to describe, and yet it exists and it coveted by some people as a desirable flavor. This flavor does vary greatly, and can be quite mild, like a slight limestone aura, or intense, akin to what I would describe as “drinking well-water.” Again, this is not to disparage a coffee, but to appreciate an idiosyncratic flavor that deserves recognition and appreciation.

A few months ago I was spending time with a coffee professional who I believe has a remarkable palate, and I asked him to criticize our Burundi Gishubi, a coffee with a distinct minerality that’s tends to be harsh if roasted improperly. He told me beforehand he had never enjoyed any coffee from Burundi or Rwanda. I was certainly nervous to have a peer critique our coffee, let alone from an origin he had never once enjoyed. After he brewed and took a few sips he told me this was the first time he had ever enjoyed an East African with these characteristics. “That mineral flavor is well integrated, and takes more of a back-seat to the overall cup instead of being the main focus.” I was so happy to hear this, and ever since then I’ve been overjoyed knowing our coffee created a positive experience for a skeptic.

I think the general disdain for this flavor profile comes not from the coffee’s inherent characteristics, but from poor roasting choices which ultimately exacerbate the mineral tones in an unpleasant way. When a roaster underdevelops (roasts too light) or uses improper roasting techniques, off-flavors will be easy to taste, and no matter how you brew those off-flavors will take the center stage instead of the inherent characteristics of the beans, or in this case, natural flavors will be completely misrepresented.

All this being said, the main way to integrate that unique flavor profile correctly is to evenly apply heat throughout the roast, and slow down the overall roast in order to create a greater homogenization of the beans. The result is more clarity, and the minerality tasting more refined than “dirty” or “murky,” as some would say.

Our Rwanda Hingakawa displays some of these outstanding mineral tones while remaining exceptionally balanced and sweet. This year’s crop for me is the best I’ve tasted so far.  On the nose I pick up a lot of complexity: chai spices, ripe stonefruits, mild citrus blossom, and candied pecans with an ethereal petrichor aroma. The flavors reflect this complexity with tones of peaches, praline, vanilla bean, browned butter, slight maple syrup, and a light “flint” finish. The cup is smooth, balanced, and an easy-drinker despite remaining on the lighter end of the roasting spectrum. The minerality is apparent and it only adds a level of complexity to the overall flavor profile. I can’t speak highly enough of this year’s crop and the hard work of the Abukundakawa women who grow such amazing fruit.

I’m looking forward to offering more stellar coffees with this specific flavor characteristic. Be on the lookout soon for another coffee from this distinct growing region near Lake Victoria.

-Roaster Nick