How Yeast’s Long Journey Affects Chocolate

As humans migrated, they brought a fermenting hitchhiker

You’re probably well aware of the delicious scientific process that is fermentation. When yeast consumers sugars, it leaves behind not only alcohol, but also complex, wonderful flavors. It’s familiar in wine and beerm but according to a recent study in Current Biology, the yeast fermentation that takes place in cacao and coffee beans might have as dramatic an effect on flavor.

Scientists at the Pacific Northwest Diabetes Research Institute in Seattle, Washington, tested coffee and cacao beans sourced from different regions around the world to analyze S. cerevisiae, the yeast that works its magic in wine, beer, and bread as well as coffee and chocolate. It turns out that as humans migrated around the globe, they brought specific strains of this yeast with them.

The researchers discovered that the yeast in a cacao bean from Ghana, for example, was very different from that in a cacao bean from Venezuela, for example. In wine, conversely, the yeast found on grapes from one part of the world is very similar to those across the globe.

{what is the explanation for this?}

Cacao ferments from 5 to 7 days, but what types of bacteria and yeast are involved with that fermentation process is not completely understood That’s partly because cacao fermentation doesn’t involve dosing with lab-grown yeasts. Instead, it happens thanks to whatever wild bacteria and yeast are naturally on the cacao.

For winemakers, yeast is an important part of the wine’s terroir, contributing to its flavor. {but terroir = geography? and wine yeast is the same around the world we just said?}

The scientists didn’t investigate whether the varying strains of yeast in chocolate and coffee beans cause variation in flavor, but their higher diversity suggests they might be a key component.