One coffee. Four fermentation processes. Four different aromatic expressions to compare in a single tasting session.
Pre-sale is open! Reserve your tasting kit now.
📅 Important Dates
- Pre-sale: now open
- September 11, 2026: The four coffees will be roasted to ensure optimal freshness for all participants.
- October 3, 2026: Simultaneous global live tasting with James Hoffmann. Thousands of enthusiasts, worldwide, will taste the exact same coffees at the same time and compare their impressions.
The Fermentation Project, conceived by James Hoffmann in collaboration with fermentation specialist Lucia Solis, will be one of the most ambitious and educational experiences offered to the global specialty coffee community in 2026.
94 Celcius will be among the participating roasters and will offer the kit in Quebec and Canada.
Each kit will contain four coffees from the same lot of green coffee. The variety, origin, harvest, and production conditions will remain the same. The main variable that will change is the fermentation process used after harvesting.
This approach will answer a question as simple as it is complex:
What effect does fermentation actually have on the taste of coffee?
The kit will contain four 100g bags, for a total of 400g of coffee:
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one mechanically demucilaged coffee;
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one coffee subjected to wild fermentation;
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one coffee inoculated with lactic acid bacteria;
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one coffee inoculated with selected yeast.
You can order your kit now here: Fermentation Project!
In summary: what is The Fermentation Project?
The Fermentation Project is an international comparative tasting experience dedicated to coffee fermentation.
The same lot of coffee produced in Guatemala was separated into four parts. Each was then processed according to a different protocol. The four coffees were distributed to participating roasters in several countries, who are to roast them and offer them as comparative kits.
Participants will be able to prepare the four coffees side-by-side and follow a guided tasting with James Hoffmann on October 3, 2026!
The goal is not just to discover four coffees.
It is to learn to recognize what different microorganisms and processing methods can change in a cup, when almost all other variables are kept constant.
Why compare a single coffee fermented in four ways?
Comparing two coffees from different farms tells us relatively little about the precise effect of their fermentation.
Even when they come from the same country, several factors can vary:
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the botanical variety;
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the altitude;
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the soil;
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the climate;
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the ripeness of the cherries;
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the harvest date;
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the drying method;
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storage;
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roasting;
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preparation.
When more fruit, more acidity, or a creamier texture is perceived in a coffee, it is therefore difficult to attribute these differences to a single stage.
The Fermentation Project seeks to reduce this problem.
In this experiment, the raw material is common to the four coffees. They come from the same project, the same origin, and the same initial lot. Fermentation thus becomes the main variable studied.
This is not a perfectly isolated laboratory experiment in the scientific sense of the term. Drying and biological reactions remain complex phenomena. But it is a much more controlled comparison than what amateurs can normally achieve by buying four different coffees.
What is coffee fermentation?
Coffee fermentation occurs after the cherries are harvested.
As with wine, beer, bread, cocoa, or certain dairy products, microorganisms use sugars and other compounds available in their environment.
These microorganisms may include:
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yeasts;
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lactic acid bacteria;
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acetic acid bacteria;
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other microbial populations naturally present on the fruits, in the water, on the equipment, or in the farm environment.
During their activity, microorganisms transform certain compounds and produce different metabolites, including acids, alcohols, and aromatic molecules.
These transformations can influence coffee in several ways:
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facilitate the removal of mucilage around the bean;
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modify perceived acidity;
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influence texture;
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change the intensity of certain fruity notes;
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promote or decrease certain aromatic precursors;
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improve batch consistency;
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cause defects when the process is poorly controlled.
Fermentation is therefore not simply a way to make coffee more "funky."
It is primarily a post-harvest transformation step that can help producers manage mucilage, drying, stability, and coffee quality.
Mucilage: the environment where part of the fermentation takes place
Beneath the skin of the coffee cherry is a pulp, then a viscous, sugar-rich layer called mucilage.
After pulping, some of this mucilage remains attached to the parchment surrounding the bean.
It then provides a source of nutrients for microorganisms. Depending on the chosen method, the producer can:
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quickly remove the mucilage with a machine;
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allow naturally present microorganisms to act;
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add a selected microbial culture;
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control duration, temperature, pH, or oxygen exposure.
The word "fermentation" therefore covers very different realities.
Spontaneous fermentation in an open tank does not necessarily produce the same result as inoculated fermentation, carried out in a closed and monitored environment.
The four processes of The Fermentation Project
1. Mechanical demucilagination
The first coffee is mechanically demucilaged.
A machine physically removes a large part of the mucilage present around the parchment. Fermentation activity can thus be limited compared to other treatments.
In the context of the project, this coffee primarily serves as a reference point.
It will allow observation of the lot's profile when less fermentative intervention is sought.
This does not necessarily mean that no fermentation occurs. Microorganisms are present throughout the processing chain. However, the rapid removal of mucilage reduces the amount of substrate available and the importance of fermentation as an intentional step.
In the cup, this coffee could more directly reveal certain characteristics specific to the raw material and origin. Nevertheless, we will have to wait for the comparative tasting before drawing conclusions about its precise profile.
2. Wild fermentation
The second coffee is from a wild fermentation (spontaneous).
In this context, the term "wild" means that the process primarily depends on microorganisms already present in the environment, rather than a specific culture intentionally added.
These microorganisms can come from:
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the surface of the cherries;
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tanks;
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water;
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air;
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farm facilities;
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previous fermentations.
Spontaneous fermentations are common in traditional coffee processing. They can create complex and distinctive profiles, but they can also be more variable.
Ambient temperature, fruit ripeness, water quality, equipment hygiene, process duration, and available oxygen can all influence the microbial populations that dominate the fermentation.
The result is therefore not produced by a single microorganism. It emerges from a complex biological ecosystem.
3. Fermentation inoculated with lactic acid bacteria
The third coffee is fermented with a culture of Lactobacillus, a group historically associated with lactic acid bacteria.
These microorganisms use certain sugars and produce lactic acid, among other compounds resulting from their metabolism.
Lactic acid bacteria are used in several fermented foods. In coffee, their interest is not limited to creating a particular acidity.
Controlled inoculation can also serve to:
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guide fermentation more quickly;
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reduce the influence of undesirable microorganisms;
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make results more reproducible;
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better control the batch profile;
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reduce certain risks associated with spontaneous fermentation.
However, it would be simplistic to say that lactic fermentation will automatically give a creamy coffee or that it will always produce an acidity reminiscent of yogurt.
The result also depends on the strain used, the substrate, time, temperature, pH, oxygen, drying, and the coffee itself.
This is precisely what makes the comparison proposed by the project so interesting.
4. Fermentation inoculated with yeast
The fourth coffee was fermented with a selected yeast.
Yeasts already play a natural role in many spontaneous fermentations. They consume certain sugars and can produce ethanol, carbon dioxide, acids, and various aromatic molecules.
Certain yeasts are selected for their ability to:
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rapidly dominate a fermentation;
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act predictably;
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tolerate certain conditions;
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improve reproducibility;
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promote the formation of particular aromatic compounds.
In wine and beer, the importance of the yeast strain is well known. Two different yeasts can produce distinct sensory results from a similar substrate.
In coffee, this relationship is even more complex since the compounds produced during fermentation must then withstand drying, storage, and roasting before being perceived in the cup.
The Fermentation Project will specifically compare a yeast-inoculated fermentation to a spontaneous fermentation and a lactic fermentation, on the same coffee base.
Controlled fermentation vs. co-fermentation: what's the difference?
These two terms are sometimes used as if they described the same thing, but this is not always the case.
A controlled fermentation generally refers to a process in which the producer monitors or adjusts certain variables:
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temperature;
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duration;
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pH;
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oxygen;
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pressure;
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type of container;
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inoculated microorganism;
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amount of mucilage;
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sugar concentration.
A co-fermentation generally involves adding another substrate or ingredient to the fermentation environment. This can be fruits, spices, plants, or materials rich in sugars and microorganisms.
In an inoculated fermentation with yeast or bacteria, a microbial culture is added to guide the process.
In a co-fermentation, another material is usually added that can participate in the fermentation and influence the sensory profile.
The Fermentation Project does not aim to compare flavored coffees or co-fermentations with spectacular profiles. Instead, it seeks to understand the fundamental mechanisms of fermentation through four distinct approaches.
Who is James Hoffmann?
James Hoffmann is one of the most influential figures in contemporary specialty coffee.
He won the World Barista Championship in 2007 and subsequently became known as an author, entrepreneur, and communicator. He is particularly recognized for his ability to make complex subjects related to extraction, roasting, equipment, green coffee, and sensory science accessible.
Through his videos, books, and global tasting projects, he has helped introduce specialty coffee to a much wider audience.
His collective experiments generally do not seek to impose a single answer.
Instead, they allow participants to taste, compare, and develop their own understanding.
The Fermentation Project precisely follows this logic: transforming a technical subject into a concrete experience that can be replicated at home.
Who is Lucia Solis?
Lucia Solis is a consultant in coffee fermentation and post-harvest processing.
She studied viticulture and enology at the University of California at Davis, specializing in microbiology and fermentation science. She then worked for nine years in Napa Valley wine production before focusing her work on coffee starting in 2014.
She now has over twelve years of international experience in coffee and has collaborated with producers in more than fifteen countries.
Her work is not simply about creating the most intense fermentations or the most surprising profiles.
Rather, she helps producers view coffee processing as a strategic tool to:
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reduce risks for profit;
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simplify protocols;
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better understand variables;
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increase consistency;
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develop reproducible profiles;
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protect or improve the value of coffee;
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make innovations applicable on a larger scale.
Her approach combines microbiological principles, operational simplicity, and the economic reality of farms.
This dimension is important.
A spectacular fermentation that works once does not necessarily have much value for a producer if it is impossible to reproduce, too costly, or too risky.
The pursuit of consistency can be as important as the pursuit of aromatic intensity.
Caravela's role in the project
Caravela acts as the project's origin partner and international distribution partner.
The company has been present in Guatemala since 2016 and works with producer communities across the country. For The Fermentation Project, its role includes sourcing, quality assurance, export operations, and the logistics required to distribute coffees to participating roasters.
This logistical component is considerable.
To keep the experiment relevant, the four lots must be:
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accurately identified;
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properly separated;
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packaged;
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exported;
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distributed across multiple markets;
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roasted within a comparable window;
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offered to participants before the global tasting event.
The Fermentation Project is therefore as much a transformation and education project as it is an international challenge of traceability and coordination.
Why 94 Celcius is participating in the Fermentation Project
At 94 Celcius, we have been interested for several years in the relationship between fermentation, terroir, and aromatic profile.
We regularly work with producers who experiment with different post-harvest processes:
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controlled fermentations;
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inoculated fermentations;
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carbonic macerations;
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anaerobic processes;
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thermal shocks;
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prolonged fermentations;
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natural coffees;
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honey processes;
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co-fermentations.
We have roasted coffees produced by Diego Bermúdez, Sebastián Ramírez, Brayan Alvear, Wilton Benítez, Elias and Shady Bayter, Carolina Ramirez, and several other producers renowned for their mastery or exploration of processing methods.
These experiences have taught us that a fermentation cannot be evaluated solely by its name.
Two coffees described as "anaerobic" can behave and taste completely differently.
To understand a process, one must also consider:
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the initial coffee;
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the variety;
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the fruit's ripeness;
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the temperature;
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the duration;
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the microbial culture;
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the presence or absence of oxygen;
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the type of tank;
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the drying method;
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storage;
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roasting.
We have also noticed that highly processed coffees require special attention during roasting.
Their density, moisture, water activity, and structure can differ. Some rapidly develop intense aromas, while others require a more delicate approach to maintain their clarity.
The Fermentation Project therefore directly aligns with our scientific curiosity and our way of working.
It's not just about selling four different coffees. It's about offering an experience that allows for a more rigorous tasting of a variable.
How will 94 Celcius roast the four coffees?
Our goal will be to develop profiles that make the comparison as clear and fair as possible.
It would not necessarily be relevant to apply exactly the same roasting profile to all four coffees without any adaptation. Different processes can alter their behavior in the roaster.
Conversely, radically different profiles could introduce a new variable and make the comparison less useful.
We will therefore seek a balance:
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a comparable final color;
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a consistent development level;
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a light enough roast to preserve differences;
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limited adjustments when a lot's physical behavior requires it;
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a common roasting window before the tasting.
Our priority will be readability.
Each coffee must remain distinct, but none should be artificially favored by a much more developed or spectacular roast.
What might the tasting look like?
The four coffees can be tasted as filter infusions or as part of a comparative cupping.
Cupping, however, has certain advantages for a comparative experience:
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the same grind is used;
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the coffee-to-water ratio is identical;
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the pouring technique has less influence;