March 30, 2023

Cup of Joe vs. The Volcano

By The Coffee Research Department
Cup of Joe vs. The Volcano

We, like the rest of America, have been swept up by the drama of HBO’s White Lotus.  Season 3’s location just dropped  (it’s going to be Thailand!!), so we got to thinking about how the show, like our other favorite addiction, is set against the volatility of mother nature. Namely, volcanoes. 

The connection between addictive TV, coffee and active volcanoes isn’t as out-there as it might seem. Season 2’s Daphne, played by Meghann Fahy, made it easy to connect the dots when she said that volcanic soil makes for really good Italian wine. 

We thought, “Of course! That’s true for coffee, too!”

This is because the properties that enrich the soil near Mt. Etna, like magnesium and iron, also benefit the coffee bean.

Location, Location, Location

Just like the White Lotus, it’s all about location. And it should be no surprise to coffee drinkers that our favorite bean grows in regions that are both visually and geographically dynamic. 

Think of earth’s active volcanoes, some situated along the Ring of Fire. Now consider places famous for coffee. Notice the overlap? They spring to mind easily: Costa Rica, Guatemala, Hawai’i, Indonesia.

Volcanic soil is rich with nutrients that plants need to thrive. Geologists call these soils “andisols” from the Japanese word an, meaning “dark,” and do, meaning “soil.”

The soils that best nourish coffee plants are formed by tephra - a mixture of volcanic ash and rock fragments that break up over time.

Minerals present in the volcanic ash can vary, which helps contribute to different flavor profiles of your favorite brew.

It can get a little technical from here. Simply put, it helps to remember that weaker volcanic eruptions produce ash composed with 55% silica, and rich in iron and magnesium. While more explosive events produce felsic ash, made up of feldspar and quartz. These are called rhyolite eruptions. All together and over time, the soil becomes rich and fertile

Another benefit of volcanic soil is that it’s porous. Drainage is very important because the roots of coffee plants have a particularly high oxygen demand. According to the European Geological Union, coffee roots require enough water retention and drainage to allow them to dig deeper and resist rotting.

Unlike dense clay or heavy sand, volcanic soil benefits our beloved coffee plants because it is so light and fluffy.

Hot Lava, Cup O’ Java

Even with active geological forces in play, farmers dare to seek out the best soil and conditions by going straight to the source - the base of earth’s fire mountains.

These geologically active slopes can be perilous. Dangers include ash clouds, hot currents of gas and ash (called pyroclastic flows), and even volcanic mudflows called lahars.

But the slopes are fruitful and have a distinct eco-advantage, a natural form of protection. Volcanic mountains provide shelter and shade which allows coffee cherries to ripen more slowly (source: Barista Mag).

Volcanoes also provide high altitudes and specialized microclimates, giving distinct advantages to the coffee growers. Higher elevations create a sweeter, higher quality bean.

It is such a delicate balance of climate, soil, shade, and altitude, that some producers claim taste profiles vary slope by slope.  According to a Panamanian farmer, plants grown on the southernmost base of Volcán Barú, have a different taste to those grown on the northern slopes.

My Thai Coffee

Even in areas where volcanoes are considered long dormant, the composition of the soil, enriched by long-ago lava flow, is prime for coffee harvests. In Northern Thailand, there is the Lampang volcanic belt, where lava fields dating back to the Pleistocene era can be found.

Though the Lampang volcano is extinct, it left behind soil that is still considered rich in minerals. Some say that volcanic ash acts as a time-release fertilizer, mixing with new soil and nourishing the most beautiful and verdant rain forests. 

Researchers found evidence of rhyolite rocks in the Chiang-Mai-Chiang-Rai region - exactly the same geographic area where coffee is grown in Thailand. No wonder Chiang-Mai is becoming known as a coffee lovers hot spot. 

Our conclusion is that it is no coincidence that volcanoes, coffee and sumptuous landscapes go hand-in-hand, in areas that are ripe for both dramatic volcanic eruptions and fertility. This is, after all, some of the earth’s prime real estate.

Will Chiang-Mai’s Four Seasons be the backdrop for the next binge-worthy season of White Lotus? Maybe. But we know one thing is certain. We’re looking forward to sitting down to watch the earth-shaking drama of White Lotus, Thai coffee addition!



Photo credit: Oliver Spalt, 1994. A small eruption of Mount Rinjani, with volcanic lightning, in Lombok, Indonesia.



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