If you’ve spent any time in health and wellness circles online, you’ve probably encountered the claim that your coffee is secretly loaded with mold and mycotoxins — invisible poisons sapping your energy, fogging your brain, and slowly wrecking your health.

We roast coffee here at Deer Run Acres. Three single-origin offerings — Ethiopia Yirgacheffe, Honduras Guama Danta, and Peru Minca — all certified organic, all specialty-grade, all roasted to order on our farm. And every time we post about our coffee, a wave of well-meaning commenters show up warning us and our customers about “mold in coffee.”

So I started digging — not into wellness blogs or influencer podcasts, but into published scientific studies, industry grading standards, and the actual supply chain mechanics of how coffee gets from a farm to your cup. I also looked at who’s funding what, because that matters. What I found confirmed what most coffee professionals already know: the “mold in coffee” scare is one of the most successful fear-based marketing campaigns in the food industry.

Here’s the full breakdown — including why you should read published research with open eyes, not blind trust.

Yes, Mycotoxins Exist in Coffee. That’s Not the Whole Story.

Let’s get the honest part out of the way first. Mycotoxins are real. They’re toxic compounds produced by certain molds — primarily Aspergillus and Penicillium species — and they can contaminate crops including coffee, grains, nuts, wine, dried fruit, spices, and even some animal products. The two mycotoxins most relevant to coffee are ochratoxin A (OTA) and aflatoxin B1.

Nobody disputes their existence. The question is whether the levels found in coffee are actually dangerous. And the answer, according to decades of published research, is no.

What the Published Research Shows

I’ll keep this section brief and link the studies directly so you can read them yourself. I’m not asking you to take my word for it — or theirs. I’m asking you to look at where the evidence points when multiple independent studies, across different countries, funding sources, and decades, all land in the same place.

A 2021 toxicology-based risk assessment published in the Journal of Food Science found large margins-of-exposure in every scenario modeled, no historical evidence of acute toxicity from coffee consumption, and concluded that no preventive control is warranted for U.S. coffee manufacturers.^[1] A 2024 worldwide systematic review of 40 studies across multiple countries reached the same conclusion: the OTA content of coffee is not toxic to consumers.^[3] An NIH-published Spanish study found that four cups of coffee per day puts mycotoxin intake at 2% of the maximum safe level.^[2]

On roasting: a peer-reviewed study in the Journal of Agricultural and Food Chemistry documented OTA reductions upward of 90% at espresso roast parameters.^[4] Multiple additional studies put the range at 69–96% reduction depending on roast level. The Codex Alimentarius (the international food standards body from the FAO and WHO) reports 65–100% reduction is achievable.^[1] And caffeine itself appears to inhibit aflatoxin damage to the liver — meaning decaffeinated coffee may actually carry slightly higher mycotoxin risk than regular coffee.^[2]

An older but foundational review indexed in PubMed noted that due to the extremely low frequency of findings, low toxin levels, and 70–80% destruction by roasting, further study on the topic was discontinued.^[5]

All twelve studies are linked in the references section at the bottom. Read them.

A Word on Scientific Skepticism — Because It Matters

If you’re reading the section above and thinking, “That’s great, but I don’t automatically trust published studies” — good. Neither do I.

In 2015, Richard Horton, the editor-in-chief of The Lancet — one of the most respected medical journals in the world — published a now-famous editorial in which he wrote:

Horton went further. He criticized journal editors — including himself — for aiding poor practices, for fueling an obsession with impact factor over truth, and for rejecting important confirmatory studies in favor of flashy original research. He noted that scientists too often sculpt data to fit preferred theories, or retrofit hypotheses to fit their data.

He wasn’t alone. Dr. Marcia Angell, who served as editor-in-chief of the New England Journal of Medicine for two decades, wrote: “It is simply no longer possible to believe much of the clinical research that is published, or to rely on the judgment of trusted physicians or authoritative medical guidelines.”^[14]

These aren’t fringe voices. These are the people who run the journals. And they’re telling us the system has real problems — problems with funding bias, p-hacking, small sample sizes, conflicts of interest, and the publish-or-perish culture that incentivizes quantity over truth.

So why am I still citing studies in this article?

Because skepticism isn’t the same thing as dismissal. The problems Horton and Angell describe are real, and they tend to be most dangerous in areas where a single study funded by a single interested party drives a narrative — which is exactly what happened with the “mold-free” coffee movement. One entrepreneur’s claims, amplified by a marketing machine, with no publicly available independent data to back them up.

The mycotoxin research on coffee is different. It spans decades. It comes from researchers in Spain, Brazil, Mexico, Iran, Italy, Switzerland, Qatar, and the United States. It includes independent university studies, government food safety agencies (FAO, WHO, EFSA, FDA), and industry bodies. The studies use different methodologies, different sample sources, and different analytical tools — and they consistently arrive at the same conclusion: the levels in coffee are not dangerous for consumers.

When one study funded by a company tells you their product solves a problem no one else can see, be skeptical. When dozens of independent studies across multiple decades and continents converge on the same finding — and that finding is also confirmed by observable industry practices and regulatory frameworks — you’re not looking at bias. You’re looking at a body of evidence.

The irony of the “mold in coffee” scare is that it preys on exactly the kind of healthy skepticism Horton was talking about. It takes your justified distrust of institutions and redirects it — not toward better thinking, but toward buying a more expensive bag of coffee from someone who also won’t show you their data.

The Marketing Machine: How Fear Became a Business Model

So if the science is this clear, why are so many people convinced their coffee is poisoning them?

Because someone figured out how to monetize fear.

The modern “mold in coffee” panic traces directly back to Dave Asprey, the creator of Bulletproof Coffee, who built an entire brand around the claim that regular coffee is “full of performance-robbing mycotoxins” and that his product — sold at a significant premium — was uniquely safe.

Here’s what’s important to understand about that claim: Asprey has never publicly released independent lab testing data that shows his coffee is meaningfully different from other specialty-grade coffees. His “proprietary processing method” is not patented — and industry professionals have widely noted that it appears to be standard wet processing, the same technique that specialty coffee has used for decades.

Meanwhile, Onnit Labs — a company that actually resells Bulletproof Coffee — commissioned their own 2013 study where they randomly tested multiple coffee brands, including Starbucks. The result? None of the randomly selected brands contained any detectable mycotoxins.^[2]

The playbook is simple and effective: take a real scientific concept (mycotoxins exist), strip away the dose-response context (the levels in coffee are negligibly low), create fear (your coffee is making you sick), and then sell the cure (our special coffee is the only safe option). It’s a textbook example of manufacturing demand through manufactured fear.

And it’s not just one brand anymore. An entire cottage industry of “mold-free” and “mycotoxin-tested” coffee brands has emerged, most of them charging $20 to $30 or more per bag. Here’s the part that should bother you: many of these brands don’t publish SCA cupping scores, don’t print roast dates on their bags, and don’t offer origin traceability — the basic markers of actual specialty-grade coffee. Which means in many cases, you’re paying specialty-grade prices for what may very well be commercial-grade coffee with a “mold-free” label on it. The label becomes the value proposition instead of the coffee itself. A well-sourced, properly stored specialty-grade coffee from a transparent roaster already has mold controls built into the supply chain — and it costs less.

What Actually Protects You: Specialty Coffee Grading

Here’s what the “mold-free” marketers don’t want you to know: the specialty coffee industry has had rigorous quality controls addressing mold for decades — long before Bulletproof Coffee existed.

The Specialty Coffee Association’s (SCA) grading protocol requires that coffee achieve a score of 80 or above on a 100-point scale to earn the “specialty” designation. Before any cupping even begins, Q-graders physically inspect a 350-gram sample of green beans for defects. Mold is classified as a primary (Category 1) defect under the SCA system, and specialty-grade coffee permits zero Category 1 defects. A single moldy bean in a 350-gram sample is enough to disqualify a coffee from specialty status.^[6]

Beyond defect inspection, the SCA standard requires moisture content between 9% and 13%. Moisture above 12.5% creates conditions favorable to mold growth, which is exactly why specialty-grade coffee maintains strict moisture standards — this has been industry practice for years.^[7]

Wet processing — the method used for most specialty-grade washed arabica coffees — effectively removes the majority of mold spores during the cherry-to-parchment stage. This is not a secret proprietary process. It’s the standard method used across the specialty coffee supply chain worldwide.

Where Mold Actually Matters

None of this means mold is irrelevant to the coffee industry. It’s a real concern in specific situations — just not the ones the marketers are selling you.

Mycotoxin contamination is predominantly associated with commodity-grade coffee — the low-cost, mass-market beans traded on commodity exchanges that make up the bulk of global production. These coffees are often harvested without selectivity, dried in conditions that promote mold growth, stored in facilities without adequate climate control, and blended from unknown origins where traceability is impossible.

A 2018 study from Mexico published in PMC found that different production stages of roasted coffee — crop management, postharvest practices, and storage — along with environmental conditions do not guarantee a mycotoxin-free product, and that OTA-producing fungi were found in commercially available roasted coffee beans from local markets.^[8]

A 2021 study analyzing coffee from the Caparaó region of Brazil found that while OTA can appear during the drying stage of processing, the specialty-grade coffees in their study — those scoring 80+ under SCA protocol — consistently showed managed mycotoxin levels. The study reinforced that proper postharvest handling is the primary control factor.^[9]

The solution to mold in coffee was never a proprietary marketing label. It was, and always has been, quality sourcing, proper processing, controlled storage, and rigorous grading — the exact things the specialty coffee industry has been doing for decades.

What We Do at Deer Run Acres

We’re a small family farm. We roast on an RK Drum setup and profile every roast with Roast Pilot software. We’re not a large-scale operation, and we don’t pretend to be. But we do take quality seriously, because quality is the whole point.

Our three coffees — Ethiopia Yirgacheffe, Honduras Guama Danta, and Peru Minca — are all specialty-grade, certified organic green beans sourced through Genuine Origin, a direct-trade importer with full traceability to origin. Every lot we purchase meets SCA grading standards. The beans are wet-processed. They’re stored properly. And we roast to order, meaning our coffee doesn’t sit in a warehouse for months before reaching your cup.

We don’t market our coffee as “mold-free” because that framing itself is dishonest. It implies that other coffee is dangerous, and that ours is uniquely safe. The science doesn’t support that distinction for any properly sourced specialty coffee. What we do instead is focus on what actually matters: origin quality, roast freshness, traceable sourcing, and certified organic beans. No gimmicks.

The Bottom Line

Mycotoxins are a real scientific concept. Their presence in coffee at trace levels is documented and uncontested. But the claim that your coffee is making you sick, that you need special “mold-free” beans, and that companies selling those beans have discovered something the rest of the industry hasn’t — that’s marketing, not science.

Peer-reviewed research consistently shows that mycotoxin levels in coffee are far below established safety thresholds. Roasting eliminates 69% to 96%+ of ochratoxin A. Caffeine itself is protective against aflatoxin damage. Specialty coffee grading systems have excluded moldy beans for decades. And multiple risk assessments — including a 2021 Journal of Food Science study and a 2024 worldwide systematic review — have concluded that coffee does not pose a mycotoxin-related health risk to consumers.

If you want to minimize any possible exposure, here’s what actually matters: buy specialty-grade coffee (SCA 80+ score), buy from a roaster who knows their sourcing, buy fresh (roasted to order if possible), and store it properly in a cool, dry place. That’s it.

Everything else is someone trying to sell you a solution to a problem that doesn’t exist.