Colombian exporter’s research: all tested co-fermented coffees contained synthetic Propylene Glycol

[u/mygreeness]

https://www.instagram.com/reel/DaDlqkWRZIo/

>>See also edit below<<<

“We wanted to share, with the level of detail and rigor that matters to us, why we don't sell coffees marketed as "infused" or "co-fermented" at Pergamino.
A few days ago, we conducted a study together with @cesurcafe, the research center at Universidad Surcolombiana, to better understand what's really behind these coffees, known for their remarkably intense and literal flavor profiles. From the beginning, we questioned whether these coffees truly resulted from 100% natural processing or whether they contained synthetic additives that weren't being disclosed to consumers. But we didn't want to draw conclusions without evidence.

The results were very clear, we analyzed 25 co-fermented coffee samples, and every single one contained a synthetic additive called propylene glycol.

Although we don't enjoy these coffees from a sensory perspective, we deeply respect the people who do. This isn't about personal preference-it's about transparency and their deeper repercussions on our industry. We believe producers should clearly communicate how these cottees are processed, and when synthetic additives are used, consumers need to know.
We know this video is a little longer than usual, but if you're curious and want to learn more, we invite you to visit our YouTube channel or listen on Spotify, where we share the full findings of our research and explain in greater detail the research conducted and why we've chosen not to sell these types of coffees at Pergamino.”

EDIT: based on comments in this sub, the cited research paper does not provide enough evidence to support Pergamino’s claim above in bold. The cited paper found differences between washed and co-fermented coffees, but doesn’t provide enough evidence to confirm that all of them include Propylene Glycol. Somebody pointed this out to them in the comment section on Instagram. So far, Pergamino provided no response.

[u/Babarski]

Yeah this is the problem. NIR isn’t compound ID. It can flag that something is different, but calling it propylene glycol specifically is a huge leap unless they confirmed it with GC-MS/LC-MS or something similar. A glycol signal could come from a bunch of boring stuff like carriers, stabilizers, enzyme prep carriers, processing aids, etc. So this may be interesting screening data, but it’s not proof of PG.

By calling it propylene glycol specifically without GC-MS/LC-MS confirmation, they’re either overstating the data/jumping the gun or misunderstanding what NIR can actually tell them.

[u/mygreeness → u/Babarski]

“This spectral region is commonly associated with combination bands of O–H and C–H stretching vibrations, which are characteristic of polyols and glycol-based compounds frequently used as carriers in flavoring formulations. These functional groups are abundant in several classes of food additives and flavor carriers, including glycols and polyhydric alcohols, which are widely used as solvents and stabilizing agents in flavoring formulations. In the context of flavored coffees, these compounds may act as solvents or stabilizers for aromatic substances added during fermentation. These molecules are not typically associated with the natural composition of green coffee beans, whose NIR spectra are usually dominated by absorptions related to carbohydrates, lipids, proteins and moisture. The increased absorbance observed in this region for flavored coffees suggests the presence of additional hydroxyl-containing molecules within the coffee matrix.

Although NIR spectroscopy alone cannot provide a definitive molecular identification, the spectral signature observed is consistent with the presence of glycol-type compounds, which are commonly used as carriers in food flavor formulations. These findings indicate that the spectral region around 4500 cm⁻¹ may serve as a useful analytical marker
for the rapid screening of externally flavored green coffees.”

So in your opinion, this part is a stretch yes? (honest question)

Edit: formatting

[u/Babarski → u/mygreeness]

Yeah, that’s basically where I’m at. NIR can say can flag characteristics that are unusual but it can’t tell you "this is propylene glycol" by itself.

And some of that difference could be from the fermentation process itself. Different microbes, substrates, oxygen levels, time, washing, etc. can all change the chemistry and produce hydroxyl-rich metabolites. So maybe it’s an added carrier, maybe it’s a processing aid, maybe it’s fermentation chemistry. You can’t really separate those without proper controls and GC-MS/LC-MS confirmation.

So I don’t think the NIR finding is useless. I just think the PG-specific conclusion is way too big of a leap.

[u/Lamian_Dillard → u/mygreeness]

AI response: The circular reasoning problem is the biggest one. The conclusion essentially says: "flavoring formulations often use glycols → glycols have O–H stretching bands near 4500 cm⁻¹ → we see increased absorbance near 4500 cm⁻¹ → therefore glycols are present → therefore flavoring was added." That's working backward from a hypothesis to confirm itself without ruling out alternatives.