The Fermentation Project · James Hoffmann × Lucia Solis · Guatemala

One coffee. Four processing methods. A global cupping event with coffee nerds from around the world.

James Hoffmann and Lucia Solis took a single lot of Guatemalan coffee and put it through four different processing methods. Four beans, same origin, completely different cups. We are one of 120 roasteries worldwide taking part—and, honestly, we’re pretty hyped about it.

What’s the story behind it?

The Fermentation Project is one of the largest globally coordinated cupping events in the coffee world. The concept: A single lot of green coffee is processed using four different fermentation methods, allowing for a direct comparison of how fermentation actually affects the coffee. No fancy co-fermentation with berries, whiskey, or gimmicks—just clean, controlled processes that reveal the true impact.

Everyone knows James Hoffmann—2007 World Barista Champion, YouTuber, author, and the voice that helped make specialty coffee a global phenomenon. Lucia Solis comes from a background in winemaking and is now one of the world’s most sought-after experts on coffee fermentation. She brings over 12 years of experience across more than 15 countries. Together with Caravela Coffee, the duo created a project that treats fermentation not merely as a marketing buzzword, but as what it truly is: one of the most exciting and variable stages in the entire coffee production process.

The four coffees

All the same coffee from Guatemala. The difference lies in the fermentation.

1. Mechanically Washed · No fermentation

The control sample. The mucilage is removed mechanically right away, with no fermentation step in between. What you taste in the cup comes 100% from the variety, terroir, and cultivation—nothing else.

2. Wild Fermentation · 48 hours

The classic approach. The local, naturally occurring microbial population breaks down the mucilage. This is how the majority of the world’s coffee is fermented—yielding vastly different results depending on the region, weather, and fermentation tank. 3. Lactobacillus Inoculated · 48 Hours

Here, the coffee is specifically inoculated with lactic acid bacteria. This introduces more organic acids—meaning more fruitiness, more freshness, and greater complexity. This is likely the coffee that delivers the biggest "wow" factor.

4. Saccharomyces Yeast Inoculated · 48 Hours

Fermented using specific wine yeast. The focus here is on developing flavor precursors—resulting in a fuller body, richer texture, and a broader flavor profile.

Why This Is a Big Deal

Fermentation has become a buzzword in recent years. Everything is "anaerobic," everything is "extended," and it all sounds a bit like voodoo. But who has ever had the chance to taste the unfermented version of the same coffee right alongside the fermented one? Hardly anyone.

That is exactly what this project makes possible: seeing—or rather, tasting—what fermentation actually changes. How much flavor comes from the variety? How much from the cultivation? How much from the processing? And what happens when, instead of a wild microbial culture, the coffee is inoculated with a specific, single culture?

Four cups. Direct comparisons. Clear answers.

The Live Event

On XXXXX, James Hoffmann will host a live cupping session on his YouTube channel. People all over the world will taste the same four coffees blind at the same time, share their thoughts in the comments, and be guided through the differences together.

Honestly: an event like this won't happen again anytime soon. If you’re interested in coffee and want to know what fermentation really does to your cup, this is the moment.

You can join in live or taste the coffees at your own pace. Either way works.

Recommendation

Taste them using the cupping method. No espresso, no complicated brewing setup—let the coffees speak for themselves. Use the same amount of coffee, the same water, the same temperature, and the same timer for all four. That’s the only way to keep it fair. What you need: a scale, four identical cups (250–300 ml), a kettle, and a spoon per person.

Enjoy the cupping!