Mold In Coffee? Here's What You Should Know

Over the first year of Coffee Break, I got asked from time to time about the impact of mycotoxins from mold in coffee.

I remember, the first time I was asked, not really understanding where this concern was coming from. And not knowing how to answer. It felt embarrassing.

But, a year later, I feel less bad about it.

The fact is that within specialty coffee that mold is a virtually non-existent problem. I can't say conclusively that it has never happens, but I haven't found a verifiable case.

Most of the public fear about coffee mycotoxins seems to be driven by an online advertising campaign, which uses this fear to sell a "biohacking" product.

After reading A LOT on the subject, and speaking to several industry pros, here are the things I think you should know about this topic.

What Are Mycotoxins?

Mycotoxins are toxic substances produced by a fungus.

The mycotoxin that is most talked about in the context of coffee is called Ochratoxin A (OTA). According to the World Health Organization (WHO), it is possible for mold to impact "a variety of different crops and foodstuffs including cereals, nuts, spices, dried fruits, apples and coffee beans, often under warm and humid conditions."

Emphasis added, by me.

The WHO also notes that,

"The most sensitive and notable effect [of OTA on animals] is kidney damage, but the toxin may also have effects on fetal development and on the immune system. Contrary to the clear evidence of kidney toxicity and kidney cancer due to OTA exposure in animals, this association in humans is unclear"

Again, emphasis by me.

My takeaways here are that,

Although there isn't an understood risk of OTA on humans, I probably won't start spreading it on my sandwiches anytime soon.
The risk of fungal activity of OTA-causing molds happens under warm and humid conditions.

Can Mycotoxins Form In Coffee?

Every credible publication and expert I consulted made it clear that the risk factor for mold in coffee comes from post-harvest handling.

The consensus was that OTA is not considered a field contaminant, meaning it develops from poor post-harvest conditions such as improper drying and storage methods.

And that tracks for me.

The fact is it takes a long time to get coffee from origin farm and into our Roastery. Most of that time is spent sitting on a pallet, in a protective GrainPro sack. Sometimes in a shipping container. Sometimes in the warehouse of a trader. And, for a while, in my own storage facility.

That's a lot of sitting in different environments before the coffee even gets roasted and ends up in your up. It doesn't take a big leap of imagination to understand what adding moisture and temperature might do an agricultural product under those conditions.

How Do Coffee Pros Prevent Mold?

The biggest lever coffee pros have is monitoring and controlling moisture exposure.

For speciality-grade coffee that means moisture checks at every step in the value chain. For all of the businesses involved, controlling moisture levels and communicating them clearly leads to higher prices at market.

There is big incentive to minimize risk, across the supply chain.

Nathaniel Hirschler of Balzac Bros coffee traders explained to me that his team checks moisture, "several times throughout the importing process, the offer sample, pre-ship sample, and arrival sample, and we verify that the moisture content is no higher than 12.5%"

Hillary Rodriguez, a Q Grader from Primavera Green Coffee told me about some of the common steps that traders and farmers are taking at origin to ensure proper storage conditions. Her breakdown was extensive and, in many ways, similar to the protocols that Balzac Bros implements.

Rodriguez said, "We have an agronomy team that works with producers who process coffee, to help them ensure that they are drying coffee to our parameters of 10-12% moisture."

So, yes, coffee is inspected A LOT on it's path from farm to cup.

Shipping containers are inspected before coffee goes in, and before coffee comes out. And traders have a protocol so that, "Any off-flavors, leaky or damaged areas, or moisture would be enough reason to reject a container." says Rodriguez.

Sensory Monitoring

Specialty coffee business is driven by sensory quality. Basically, the better a green coffee tastes the higher price it commands at market.

And, behind the scenes, there is a whole segment of the industry focused on quality grading. These efforts are largely driven (and standardized) by a non-profit called the Coffee Quality Institute.

There is an army of pros testing coffee for defects and sensory quality. Those with a certification are called Q Graders, and you'll find them up and down the supply chain.

Chris Kornman, the Education and Lab Manager at Royal Coffee, wrote in his two-part series on this topic: "The long and the short of moldy green coffee is that, even after roasting, it generally tastes like mold. I’d encourage you to avoid that flavor in your coffee."

Hirschler, also a Q Grader, echoed this sentiment and explained some of the criteria his team uses on a daily basis. "Coffees with mold will have a moldy flavor when tested on the cupping table. This defect is cause for a sample rejection for specialty importers and roasters alike."

For Coffee Break, we cup lots of coffees before choosing which ones to offer in our community. I haven't gone through the extensive Q Certification process (yet) that all of our supply chain partners have, but I can say that we won't offer a coffee with off flavors.

What You Can Do

For your average coffee drinker, who doesn't have time or energy to understand the full coffee supply chain, the best way to avoid mold concerns is to buy from reputable roasters who source high-quality beans and prioritize transparency.

Here are a few tips,

Choose Specialty Coffee: Specialty-grade coffee undergoes rigorous quality control measures including consideration for moisture and defects.
Avoid Bargain Coffee: Low-cost, mass-produced coffee may lack the safety nets of specialty coffee.
Trust Your Taste: Moldy coffee tastes... moldy. You might be surprised in the ability of your palate to detect off-flavors.

Another thing to consider is that, according to an article by The Sprudge, "an average adult would need to consume up to 410,000 8 oz servings of brewed coffee per day to exceed safe levels" of mycotoxins.

So, there's that.

The Bottom Line

The fear of mold in specialty coffee is largely overblown.

More than anything else, "mold in coffee" seems to be a marketing tactic used by a small handful of brands that want to capitalize on fear.

Rodriguez had a similar take, "Honestly, it's just a health fad. In the past, health influencers and entrepreneurs made big money convincing people that there was some kind of problem with their coffee, and selling high-priced solutions."

At the top end of the coffee market, like the coffees we roast, where coffees are achieving above an 85 cup score this is very (very) unlikely to be an issue.

There are many safeguards in place across the supply chain to ensure these coffees are dried, processed, packaged, shipped, and roasted correctly. Including health and safety standards set by the FDA.

There are a ton of better (or more scientific) publications commenting on this issue. If you want to dig deeper, here are a few great ones to read next:

So what do you think?

Send your comments, questions, or objections this way. And, if you liked this article, let me know. I'll try to periodically address topics like this that are reaching our community.

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