It was just a couple of weeks ago that we were wondering in the store how brewing coffee or pulling espresso differs at higher altitudes. We’re basically at sea level here, but we’d been talking about the kind of coffee some of us have found in the higher elevations of Montana — more bitter and like ‘coffee water’ than what we make and drink here.
We found the answer in this interesting piece on coffee in Santa Fe, NM. A Qasimi discusses how the higher altitude affects brewing and roasting:
I don?t drink home-brewed coffee in Santa Fe. I?ve often found it sour and lacking in the depth, robustness and natural sweetness that makes great coffee great. How does high altitude affect coffee and espresso quality at home and with the use of commercial equipment? Drip coffee machines that merely boil are convenient devices but they deliver water to the grounds at below the ideal range of temperatures, leading to underextraction of the beans and a sour, dull or poorly developed brew.
Thus, the only way to compensate for altitude is pressure — and that means espresso — but pulling a proper espresso shot is not easy at this altitude either. Ironically, though the best coffee grows at higher altitudes, with water?s lower boiling point in elevated places, brewing can get tricky. Roasting, on the other hand, merely benefits from altitude: The best possible results come from roasting the beans at the same altitude as they?ll be used and particularly at high altitudes that allow for faster roast development at lower temperatures