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In specialty coffee, few subjects have generated as much curiosity, excitement, and discomfort in recent years as so-called “infused” or “co-fermented” coffees. These coffees often arrive with striking, almost unbelievable flavor notes: strawberry candy, banana, kiwi, lychee, grape, cherry, or Tahiti lime. For many consumers, they are exciting because they deliver exactly what the label promises. For many coffee professionals, however, they raise difficult questions.
At Pergamino, this topic has become impossible to ignore. After years of tasting coffees from Colombia and around the world, across countless varieties, origins, and processing methods, we began encountering cups whose sensory profiles simply did not add up. The flavors were not merely fruity, floral, or expressive. They were literal. A coffee did not remind us of strawberry; it tasted unmistakably like strawberry. Another did not suggest banana; it tasted like banana candy. The intensity and clarity of these notes felt unlike anything we had experienced through traditional coffee fermentation.
We want to begin with honesty: we have a sensory bias. We do not enjoy these coffees. That is subjective, of course. Taste always is. Some people love intense natural-process coffees, winey profiles, strong fermented notes, or flavor-driven experiences. Others prefer elegance, subtlety, and clarity. Our own preference leans toward coffees that express complexity through nuance rather than obviousness.
But this conversation is not only about taste. It is about transparency.
If a coffee tastes literally like fruit because it has been processed with fruit, flavoring agents, stabilizers, or other external compounds, consumers deserve to know. Producers, roasters, importers, exporters, and coffee shops should be honest about what is being sold. Innovation is not the problem. Lack of clarity is.
What Natural Coffee Fermentation Actually Does
To understand why these coffees raise questions, we first need to understand how traditional coffee processing works.
In specialty coffee, quality is shaped by many factors: variety, altitude, climate, soil, agricultural practices, harvest selection, processing, drying, storage, roasting, and brewing. Among those, farm-level processing plays an especially important role. Processing usually involves some form of fermentation, followed by drying.
Fermentation begins almost as soon as coffee cherries are harvested. Microorganisms naturally present on the fruit, in the environment, and in the processing space begin acting on sugars, mucilage, and other compounds. These microorganisms produce aromatic and flavor-related compounds that influence the final cup.
In washed coffees, fermentation is often used to break down mucilage before washing. In honey processes, the coffee is depulped but dried with some mucilage still attached. In natural-process coffees, the seed dries inside the whole cherry, surrounded by fruit. In all cases, microbial activity contributes to the aromatic complexity of the coffee.
This is important: natural fermentation can absolutely affect flavor. It can create fruitier, more floral, more wine-like, or more complex profiles. A natural process might intensify ripe fruit notes. A carefully managed fermentation might increase sweetness, acidity, or aromatic depth. But these effects usually remain within a range of subtle sensory associations.
When cuppers say a coffee has notes of cherry, jasmine, bergamot, red apple, or tropical fruit, they usually do not mean the coffee literally tastes like those things. They mean the coffee evokes those references. It reminds us of them. The language of coffee tasting is associative, not literal.
That distinction matters.
A traditionally fermented coffee may remind someone of cherry. A so-called co-fermented coffee might taste exactly like cherry candy. Those are very different sensory experiences.
Why “Infused Coffee” Was Always a Problematic Term
When these coffees first appeared, many were marketed as “infused coffees.” The term caught attention, but from a technical perspective, it was inaccurate.
Infusion usually refers to extracting compounds from a solid into a liquid. Tea is a classic example: hot water extracts compounds from tea leaves. Coffee brewing itself is an infusion process in this sense.
But with these coffees, the process appeared to be the reverse. Instead of extracting compounds from coffee into water, external compounds seemed to be added into the coffee matrix. Calling that “infusion” blurred the reality of what might be happening.
Eventually, the terminology shifted. “Infused” started to sound too artificial. It suggested that something had been added. “Co-fermented” sounded more natural, more sophisticated, and more aligned with the language specialty coffee had already embraced.
A coffee “co-fermented with fruit” sounds innovative. It sounds agricultural. It sounds like a creative fermentation technique involving cherries, bananas, strawberries, or citrus. It sounds connected to the farm.
But that explanation never fully satisfied us.
Why Fruit Alone Did Not Explain the Flavor
At Pergamino, we have conducted our own experiments over the years. We have added yeasts, fruits, leaves, herbs, lemongrass, mint, lemon verbena, and other materials during fermentation or drying.
The results were interesting, but not magical.
In some cases, parchment coffee and green coffee absorbed strong aromas from herbs or other materials. The coffee could smell intensely of lemongrass or mint before roasting. But once roasted, those aromas largely disappeared.
That taught us something important: coffee can absorb aromatic compounds, but not all of those compounds survive roasting.
Coffee roasting reaches temperatures around 200°C. Many delicate volatile compounds degrade, transform, or disappear at those temperatures. If a coffee truly tastes like banana, strawberry, or grape after roasting, the question becomes: what allowed those flavor compounds to survive?
When we fermented coffee with fruit, the results could become fruitier. But they never tasted literally like strawberry, banana, or kiwi. Even with commercial yeasts from the wine or beer industries, the effect was never as clear or as intense as what we were tasting in coffees marketed as co-fermented.
That gap between explanation and experience is what pushed us to look more closely.
The Consumer Frustration Specialty Coffee Helped Create
There is another side to this story: consumer expectation.
For years, specialty coffee has used increasingly specific flavor descriptors. Bags often list notes such as lychee, pomelo, jasmine, bergamot, mango, cacao nibs, panela, or red currant. For professionals, these descriptors are references. For consumers, they can sometimes feel like promises.
A customer buys a bag that says “lychee” and then struggles to find lychee in the cup. Maybe the coffee is no longer fresh. Maybe the roast profile changed the expression. Maybe the brewing recipe was off. Maybe the consumer has never tasted lychee. Maybe their palate simply perceives the coffee differently.
That can be frustrating.
Then along comes a coffee that tastes exactly like lychee. Suddenly the consumer feels validated. “Finally,” they might think, “this is what specialty coffee was supposed to taste like.”
In that sense, the industry may have helped create the demand for extremely literal flavor experiences. By using highly specific notes as marketing language, we may have unintentionally trained consumers to expect flavors that traditional specialty coffee was never meant to deliver so literally.
At Pergamino, this is one reason we often prefer broader sensory categories. Instead of forcing a consumer to find lychee, we might say “fruity.” Instead of naming one specific flower, we might say “floral.” This gives guidance without turning tasting into a rigid expectation.
Coffee is personal. One person might perceive red apple where another finds strawberry. That subjectivity is part of the beauty of coffee. But when products start delivering literal fruit-candy flavors, the benchmark changes.
And that can distort how people understand quality.
Why Flavored Coffee Has Traditionally Been Separate from Specialty Coffee
For decades, specialty coffee has generally kept a distance from flavored coffee. A black V60 brewed with vanilla-coated beans would not typically be considered specialty coffee in the strict sense, even if someone enjoyed drinking it. A caramel frappé may be delicious, but it belongs to a different category.
The reason is simple: external flavoring changes the product.
If coffee is flavored after roasting with vanilla, hazelnut, caramel, or another additive, the industry generally expects that to be declared. Consumers understand that they are buying flavored coffee.
The concern with some co-fermented coffees is that they may occupy a gray area. They are often marketed as if their flavors emerge naturally through fermentation, fruit contact, or innovative processing. The consumer may believe they are tasting terroir, variety, origin, and fermentation skill, when in reality external compounds may be playing a significant role.
That is why the issue is not whether people should be allowed to enjoy these coffees. They should. The issue is whether they are being told clearly what they are drinking.
The Scientific Question
For a long time, we had suspicions but not evidence. Sensory experience told us something was unusual, but sensory judgment alone is not enough. We did not want this conversation to rest only on preference, philosophy, or speculation.
That is why we became interested in scientific analysis.
Together with researchers from Surcolombiana University in Neiva, Colombia, and the Cesurcafé research group, a study was conducted to compare conventionally processed green coffees with coffees being sold commercially as co-fermented coffees.
The purpose was not to attack specific producers, farms, or brands. Names were not disclosed. The goal was to investigate whether coffees marketed as co-fermented showed chemical fingerprints different from conventionally processed coffees.
Cristian, a member of Pergamino’s quality team and an Agroindustrial Engineer from Surcolombiana University, helped explain the study and its implications.
The central tool used was Near-Infrared Spectroscopy, commonly known as NIR.
What Near-Infrared Spectroscopy Does
Near-Infrared Spectroscopy is a technology widely used in food science. It works by directing near-infrared light at a sample and measuring how the material absorbs and reflects that light.
Every material interacts with light differently depending on its chemical composition. The resulting pattern is known as a spectral signature or fingerprint.
One of the advantages of NIR is that it is non-destructive. Green coffee beans can be analyzed without being chemically altered or destroyed. The technology is already used in different areas of coffee analysis, including moisture estimation, caffeine analysis, and quality control.
In this study, the researchers used NIR to look for differences between two groups of coffees: conventionally processed coffees and coffees marketed as co-fermented.
The study analyzed 79 conventionally processed green coffee samples and 25 samples sold as co-fermented coffees. These samples came from different regions and producers in Colombia.
Each coffee generated a spectral fingerprint. The researchers then used chemometric models and machine learning to interpret the data.
Chemometrics applies mathematical and statistical tools to chemical data. Machine learning can help classify patterns in large datasets. At first, the raw spectral data may look chaotic, with many overlapping signals. But after processing, meaningful patterns can emerge.
And in this case, they did.
What the Study Found
The conventionally processed coffees showed the expected chemical profile of green coffee. Their fingerprints reflected compounds naturally found in coffee: water, proteins, carbohydrates, cellulose, starches, lipids, polysaccharides, and other normal components.
The coffees marketed as co-fermented showed something different.
A specific spectral region consistently distinguished them from the conventional coffees. That region was associated with chemical bonds linked to glycols and polyols.
Glycols and polyols are alcohol-based compounds widely used in the food industry. Some, such as propylene glycol, can function as carriers or stabilizers for flavors. They help preserve, distribute, and stabilize flavor compounds in processed foods. They can also help flavors remain consistent under changing temperature conditions.
This matters in coffee because roasting is a high-temperature process. If delicate fruit flavor compounds are expected to survive roasting, some form of stabilization may help explain how they remain detectable.
The study did not determine the exact quantity of these compounds. It also did not identify every specific additive or flavoring agent involved. NIR, in this context, showed presence or absence of a spectral fingerprint; it did not provide concentration levels.
That limitation is important. The study does not prove that these coffees are unsafe. It does not make health claims. It does not determine whether any detected compounds exceed regulatory limits. That would require additional analysis.
What the study does suggest is that coffees marketed as co-fermented showed spectral signatures associated with external compounds not normally found in conventional coffee in the same way.
That is a significant finding.
Why Glycols and Polyols Matter
One possible response is: could these compounds come from fruit?
According to the discussion with the researchers and the scientific interpretation presented, the answer was no in the relevant sense. The detected signatures were not explained simply by fruit being added to coffee during fermentation.
Glycols and polyols, as discussed in this context, are commonly associated with additives and stabilizing systems used in food applications. Their presence raises legitimate questions about whether external flavoring systems are being used.
Again, the issue is not necessarily safety. Many additives used in the food industry are legal and widely consumed when used within approved limits. Propylene glycol, for example, is used in many processed food products.
The issue is disclosure.
If such compounds are being used in coffee processing, consumers should know. If a coffee is being sold as 100% coffee but includes external additives, that should be declared. If a product is flavor-enhanced, it should be labeled accordingly.
Otherwise, the industry risks misleading consumers.
The Study’s Three Main Conclusions
The investigation led to three major conclusions.
First, Near-Infrared Spectroscopy proved to be a rapid, effective, and non-destructive method for detecting differences between conventionally processed coffees and coffees marketed as co-fermented.
Second, the study identified a specific spectral region associated with chemical bonds linked to glycols and polyols. This region consistently distinguished the two groups of coffees.
Third, the technology could become a useful tool for future evaluation when there are questions about whether external flavoring agents have been used.
This is not the end of the scientific discussion. It is the beginning.
Future studies could identify the exact compounds present, measure their concentrations, compare roasted and green coffee samples, and evaluate a wider range of processing methods. More advanced laboratory techniques would be required to answer those questions definitively.
But the current findings already provide a foundation for asking better questions.
The Philosophical Problem
Beyond the chemistry, there is a deeper philosophical concern.
Specialty coffee has always been built on complexity. A great coffee is not created by a magic formula. It emerges from the interaction of genetics, environment, farming, harvesting, processing, drying, storage, roasting, and brewing. It is science, but it is also craftsmanship. It contains uncertainty, intuition, skill, and beauty.
There is no simple recipe for producing an 87-point coffee. There are best practices, but no guarantee. That is part of what makes specialty coffee special.
The concern with flavor-driven co-fermented coffees is that they may reduce this complexity to a formula. If the goal becomes making a coffee taste like banana, grape, cherry, or lychee through reproducible flavor systems, then the competitive advantage shifts away from terroir and craftsmanship and toward manufacturing.
That changes the nature of the product.
It also changes who is likely to win.
In the short term, some producers may benefit from these coffees. Some have gained visibility and high prices. That should not be dismissed. But if the process is reproducible, basic economics suggests that more producers and larger companies will eventually copy it. Supply will increase. Prices will fall. What seems like differentiation today may become commoditized tomorrow.
If success depends on facilities, tanks, food engineers, additives, and industrial consistency, then the advantage may eventually move toward larger operations with greater resources.
That should concern anyone who cares about small and medium-sized producers.
Are These Coffees Specialty Coffee?
This question is difficult because “specialty coffee” means different things to different people. Some define it by cup score. Others by traceability. Others by sensory excellence, ethics, or absence of defects.
From our perspective, coffees that rely on external flavoring systems do not represent specialty coffee as we understand it.
That does not mean they should not exist. It does not mean people should not enjoy them. It does not mean they have no market.
But they belong in a different category.
They are flavor-driven coffee products, not pure expressions of variety, terroir, and traditional processing.
One useful comparison is the wine industry. Wine has embraced innovation: stainless-steel tanks, selected yeasts, controlled fermentation, and advanced cellar technology. But if a prestigious winery secretly added undeclared synthetic flavor compounds to make a wine taste more like raspberry or vanilla, it would be a scandal.
Coffee should hold itself to a similar standard of honesty.
The Risk to Consumer Expectations
Perhaps the biggest long-term risk is not chemical. It is cultural.
If consumers begin to expect coffee to taste literally like lychee, grape candy, banana, or strawberry, then traditional specialty coffees may start to seem disappointing. A washed Geisha that delicately evokes jasmine, bergamot, and tropical fruit may feel subtle compared with a coffee that tastes like fruit juice or candy.
But subtlety is not failure. Elegance is not weakness.
Some of the world’s most extraordinary coffees are celebrated precisely because they are layered, delicate, and expressive without being overwhelming. They invite attention. They do not shout.
If flavor-enhanced coffees become the benchmark for what “good coffee” tastes like, then the industry risks devaluing the very qualities that made specialty coffee meaningful in the first place.
The Legal and Ethical Dimension
There is also a labeling issue.
In many countries, if a product is sold as 100% coffee, it must be exactly that. If it contains something else, that should be declared. This is not only a philosophical matter; it can become a legal one.
Food labeling exists so consumers know what they are buying. If additives are used, they should be disclosed. If flavoring agents are present, consumers should be informed. If stabilizers or carriers are involved, they should not remain hidden behind vague language.
Transparency protects consumers. It also protects producers, roasters, and the credibility of the industry.
Without transparency, trust erodes.
The Call for Transparency
At Pergamino, our position is clear.
We do not like these coffees from a sensory perspective. We do not believe they represent what specialty coffee means to us. We will not sell coffees in our roasting business, export business, or coffee shops when we have reason to believe they have gone through these types of flavor-enhancing processes.
But our goal is not to prohibit them. It is not to tell people what they should enjoy. It is not to claim that all innovation is bad.
Coffee should innovate. Producers should experiment. The industry should ask new questions and explore new possibilities.
But innovation should not come at the expense of transparency.
If a coffee is co-fermented with fruit only, say so clearly. If external flavorings are used, say so clearly. If stabilizers, carriers, or additives are part of the process, say so clearly. If a coffee is flavor-enhanced, label it as such.
Then consumers can decide for themselves.
Some may still love these coffees. That is fine. Others may avoid them. That is also fine. What matters is that the decision is informed.
A Beginning, Not an Ending
The research discussed here does not answer every question. It does not identify every compound. It does not quantify concentration. It does not make health claims. It does not close the debate.
What it does is open the door to a more serious conversation.
It gives us a scientific basis for asking whether some coffees marketed as co-fermented may contain external compounds. It challenges simplistic explanations. It invites further research. And most importantly, it brings us back to the central issue: honesty.
Specialty coffee was built on the idea that origin matters. That producers matter. That variety, terroir, process, and craftsmanship matter. It was built on the belief that coffee can be more than a commodity because it carries the story of a place and the work of people.
If we want to protect that, we need transparency.
Not certainty. Not dogma. Not fear of innovation.
Transparency.
Consumers deserve to know what is in their cup. Producers deserve a market that values authenticity. And the industry deserves a future built on trust rather than mystery.
That is the conversation we need to have now.