Article Summary:

This article explores the rise of co-fermented coffee, a relatively new processing method where producers introduce non-coffee ingredients such as fruits, spices, or hops into the fermentation process to enhance flavor and complexity. While some traditionalists criticize the practice as “adulteration,” others see it as the next evolution in coffee craftsmanship. Drawing on parallels with winemaking and cider-making, the article examines regulatory gray areas, labeling challenges, and the balance between innovation and transparency. Featuring insights from Edwin Noreña of Finca Campo Hermoso in Colombia and commentary from leading industry professionals, it highlights the scientific, cultural, and ethical dimensions of co-fermentation, urging the coffee community to foster open dialogue while preserving creative integrity.

Additive Fermentation: “Infused” Coffee is Gaining Popularity and Sparking Industry Debate”

From an article first published by Roast Magazine. 

Upon receiving a gift bottle of co-fermented apples and grapes recently, I thoughtlessly posed the question, “Is it a cider or a wine?” My friend responded, “It’s both!” Perhaps a purist would respond differently, saying, “It’s neither!” Fluid definitions in beverage-making constantly challenge traditional understanding of our crafts. 

 In coffee, innovations in processing methods have become increasingly common. Successfully produced anaerobic and carbonic styles of fermentation regularly take top spots in cup quality competitions and top billings on roasters’ menus. Even honey processing is only a few decades old (“limited commercial volumes” were first available in 1993 per Robert Griffith, owner of Capricorn Coffee, an exporter in Brazil), and there was a time in distant history when washing and fermentation were experiments rather than the norm. 

 Yet nothing seems to irk traditionalists more than when you suggest infusing a coffee fermentation tank with anything other than depulped coffee cherries, water, yeasts and bacteria. Concerns about this type of fermentation “adulteration” range from potential allergen contamination to “cheating” in quality competitions. 

Coffee Fermentation Additives 

Fermentation for coffee has long been a simple matter of practicality—processors harnessed the power of bacteria and yeasts to extract the coffee seed from its fruit. It wasn’t viewed as a quality additive process; it was risk mitigation—reducing the amount of material separating us from the green bean, thereby reducing processing risk and improving consistency. 

However, the past 10 years or so have proven to the specialty industry that fermentation also has potential to be additive. One trend among some coffee professionals is to take that “additive” principle as literally as possible by co-fermenting—or infusing—coffee pulp or whole coffee fruit with extra ingredients. (Let’s draw a quick distinction between “inoculation,” where a processor adds a starter culture—usually a known strain of yeast—to control the microbial population, and “co-fermentation,” where processors add food products to the slurry.) 

The most common non-microbial substrate additive is fruit, but I’ve also seen hops, spices, organic acids and even pressed coffee pulp and juice—usually the runoff of a prior fermentation batch, sometimes called “must” or “mossto” in Spanish (in yet another example of wine language contorted into the coffee lexicon, as wine “must” is simply unfermented crushed grape juice and solids)—added to a coffee fermentation. 

For roasters who sell their product to customers, there are understandable concerns about transparency in labeling and adherence to the U.S. Food and Drug Administration (FDA) guidelines. If something other than coffee is included in the bag of roasted beans, it would need to be labeled as such. However, for practical purposes when it comes to post-processing export, roasting and packaging, a co-fermented coffee is currently considered 100 percent green coffee—just like any other raw coffee product. 

Allergens are another major consideration here, and one on which the jury appears to still be deliberating regarding co-fermented coffees. For ingredients of concern, best practice would likely dictate full clarity on inputs. However, industry and government standards are quite lax with regard to green coffee in general, which is seen as a low-risk product and generally exempt from most produce regulations other than the FDA’s “Good Manufacturing Practices,” which do not include language on listing co-fermented ingredients. Furthermore, because coffee undergoes a “kill step” by roasting and brewing, it is considered generally safe for consumption regardless of major flaws. To show the extent of this lack of regulation, existing language for green coffee from the FDA is unrestricted and considered fit for consumption even when including “adulteration” with live mold and/or insects at up to “10 percent by count of green coffee beans, or [better] than Grade 8 on the New York Green Coffee Association” standards, which allows an equivalency of 450 standard defects in a 350-gram sample. 

 Suffice it to say that guidance is lacking. Under current legal regulations, it does not appear that co-fermented coffees require any different handling or labeling than conventional beans. They are neither “fortified” nor “enriched” under current definitions, and it’s unlikely that any current regulatory body would recognize co-fermented coffee as anything other than green coffee. As a result, these experimental processes are not currently subject to any additional prerequisites. 

Coffee “Must” Ferment 

Amanda Amato, coffee trader at Royal Coffee, buys a small amount of infused coffee from Edwin Noreña of Alquimista Specialty Coffee and Finca Campo Hermoso in Quindio, Colombia. Among Noreña’s more inventive coffees, his Black Ginger Ale Gesha is among the most complex and complicated, tasting quite a bit like fresh ginger, lime, hops and margarita mix. 

Edwin Noreña, Finca Campo Hermoso

The process is described by Noreña as “black honey double carbonic maceration mossto and galaxy hop” infused. The inclusion of hops in fermentation is unusual but not unheard of, despite the fact that hopping and fermenting in traditional beermaking are distinct processes. 

The hops aren’t nearly as attractive to bacteria and yeasts as sugars and pectins in the coffee mucilage. But the roasted coffee does taste hoppy. (Noreña also does an aji-chili-infused ferment, which might be my love language). Does simply spending time together in a fermentation chamber impart new flavors? It’s probable. 

“Obviously, it does work,” Amato says, discussing flavor profiles, “otherwise they wouldn’t taste like ginger ale or hops.” While there are many iterations of failed or flawed attempts at such flavor-alteration, the success stories taste unique, and also distinctly like coffee, just with the volume turned up a little on the primary flavors, something quite different from a “flavored” coffee from a roasting facility. 

Noreña’s audacious-sounding coffee could be taken as evidence of the producer’s (figurative) intoxication with fermentation’s power. However, for Noreña, his application of these processes is intended to be in service of the coffee’s inherent flavors, emerging out of respect. “It was a development that we adapted from the world of wine to enhance the flavors of coffee, always trying to intensify each coffee process using the original coffee flavors.” 

This is evidenced by Noreña’s reliance on the coffee’s mossto as a primary additive. He’s literally just adding extra coffee juice and selected microbes from a previous fermentation batch of the same cultivar. “Mossto is a catalyst that helps to accelerate, control and enhance chemical reactions during coffee fermentation,” he explains. 

Consider that the native yeasts and bacteria from a previous coffee batch will be naturally preselected as advantageous for the fermentation of coffee pulp, not to mention well-fed and energized. Rather than removing this biological fermentation engine and starting over from scratch for the next fresh batch of coffee, Noreña’s addition of “charged” mossto may improve the efficiency of fermentation for the new lot. 

Applying the principle to a co-fermentation, if a microbe population is already suited to a non-coffee additive such as oranges, might we assume that the resulting flavors in such an environment are the result of the work of the increased diversity of biological infusion (yeasts and bacteria), in tandem with the additive (the fruit or other substance) itself? More studies must be done to better understand this distinction. 

Transparency and the Way Forward 

The clarion cry from those sensitive toward a potentially problematic type of processing is for a higher degree of transparency. We must know everything about the techniques to ensure purity of the product, goes the argument. 

I was pleased to find that I’m not alone in experiencing some hesitancy to expose proprietary techniques that lead to great results for producers whose livelihoods may be dependent on a flavor note and cup score. Tim Heinze asks, “If a producer is able to hit the desired flavor note by adding something during processing, why do they have to disclose their competitive advantage?” 

In the context of disclosure, there’s much that industry actors in consuming countries still obscure. Roasters rarely reveal blend components beyond country or macroregional designations, to the extent that, famously, a “Kona Blend” may be a little as 10 percent product from the Kona districts of the Big Island of Hawaii. Is it possible that our calls for transparency from producers are bordering on a double standard? 

To answer that, a deeper question that’s worth considering and answering clearly is whether fermentation additives are considered “ingredients.” If so—the implication being that the finished green coffee product is partly something else (fruit or spice infused into the coffee)—clarity in labeling should be a requirement, particularly in the case of potential allergens. If not—which is to say, the green coffee’s flavor may be impacted but its nature as a raw product is not substantively altered, at least not more so than any other currently accepted method of post-harvest handling—then the “ingredient” list need only be published at the processor’s discretion. 

Simply put, the essential question for co-fermented coffees, still waiting for an answer from either science or industry or some combination thereof, is whether we should be categorizing them as something distinct. 

It could easily be argued that, unlike that bottle of co-fermented grapes and apples, a co-fermented coffee isn’t a multi-product blend. The final output is still just green coffee. The alternative is that we begin labeling with a far higher degree of stringency co-fermented coffees, from green to roasted and brewed states—informing a change in the name and identity of the final beverage. 

Accordingly, if you or I choose to buy and sell co-fermented coffees, implicit in that decision is to fulfill certain responsibilities to both our supply network and our customer base. This leads us ultimately back to the question of whether the differentiated categorization of co-fermented coffees is warranted, and to what types of labeling and transparency requirements may or may not be appropriate to best serve each actor in the coffee chain. 

FAQ: Co-Fermented Coffee

1. What is co-fermented coffee?
Co-fermented coffee is produced by adding non-coffee ingredients, such as fruit, hops, or spices, during fermentation to enhance flavor and complexity.

2. How is co-fermentation different from inoculation?
Inoculation introduces a known yeast or bacteria strain to guide fermentation. Co-fermentation adds a completely different substrate, such as fruit or herbs, into the process.

3. Is co-fermented coffee safe to drink?
Yes. The roasting process eliminates potential pathogens, and co-fermented coffees are currently treated as standard green coffee under FDA guidelines.

4. Does the FDA regulate co-fermented coffee?
No. Co-fermented coffee is classified as “green coffee” and is not subject to special labeling or allergen requirements.

5. Does co-fermentation make coffee “flavored”?
No. Flavored coffee has oils or extracts added after roasting. Co-fermentation alters flavor naturally during fermentation, before the beans are dried and roasted.

6. Why is there controversy around co-fermentation?
Traditionalists worry it blurs authenticity and complicates transparency. Advocates view it as an extension of coffee’s natural fermentation science.

7. Who are some notable co-fermented coffee producers?
Producers like Edwin Noreña in Colombia have pioneered innovative co-ferments using ingredients such as hops, chili, and fruit, often combined with mossto from previous fermentations.

8. How should roasters label co-fermented coffees?
While not legally required, best practice is to disclose the process and additives clearly to maintain consumer trust and transparency.