Does Espresso Have Mycotoxins? Separating Fact From Hype

December 29, 2025 •

4 min read

Multiple studies have shown that high-temperature roasting can reduce ochratoxin A (OTA) levels in coffee beans by a significant margin, sometimes by as much as 96%. The question of mycotoxins in coffee, including espresso, has become a popular topic of debate, fueled by health-conscious marketing and misinformation.

Quick Summary

Trace amounts of mycotoxins can be present in green coffee beans, but strict quality controls, roasting, and the espresso brewing process work to minimize the risk for consumers. Regulatory bodies worldwide set and monitor safety limits, which commercial coffee products almost always fall well below.

Key Points

Low Risk, High Safety: While mycotoxins can exist in raw coffee beans, processing, roasting, and espresso brewing reduce their levels to below internationally regulated safety limits.
Roasting is Key: The high heat during roasting, especially for darker roasts, is highly effective at destroying mycotoxins like OTA.
Espresso Brew Advantage: The high pressure and short brew time of an espresso machine extract fewer mycotoxins compared to other methods like auto-drip or moka pots.
Quality Matters: Specialty-grade, high-altitude Arabica coffee that is wet-processed has the lowest risk of mycotoxin contamination.
Myths and Marketing: Be wary of brands that market their coffee as uniquely "mycotoxin-free," as the term is unregulated and their claims are often unsubstantiated compared to standard specialty coffee.
Avoid Decaf and Instant (if concerned): Decaffeinated and instant coffees may sometimes contain higher mycotoxin levels, as caffeine naturally inhibits mold growth.

The Science Behind Mycotoxins in Coffee

Mycotoxins are toxic compounds naturally produced by certain fungi, such as Aspergillus and Penicillium, that can grow on crops like coffee beans under specific conditions. The two mycotoxins most relevant to coffee are Ochratoxin A (OTA) and Aflatoxin B1. OTA is associated with kidney issues, while Aflatoxin B1 is a known carcinogen, and their potential presence has become a concern for some health advocates.

Contamination typically occurs during pre-harvesting, processing, or storage if the beans are exposed to warm, humid conditions. However, it is crucial to remember that the mere presence of mold does not automatically mean mycotoxins are present. The coffee industry has long been aware of this risk and has implemented robust measures to mitigate it.

How Coffee Processing and Roasting Reduce Mycotoxins

The journey from green coffee bean to a shot of espresso involves several stages that act as natural barriers against mycotoxins. The initial processing of the coffee cherries is critical. The 'wet' processing method, common for high-quality Arabica beans, involves washing the cherries, which is highly effective at removing most surface molds and mycotoxins. In contrast, lower-quality 'commodity' coffee often uses the 'dry' method and can be more susceptible to mold growth.

Following processing, the roasting stage is arguably the most significant step in ensuring a safe product. Studies have repeatedly shown that the high temperatures used during roasting can destroy a substantial portion of any remaining mycotoxins. This thermal degradation is why darker roasts generally have lower mycotoxin levels, though some reduction occurs even at lighter roasts. Darker roasts may sacrifice some flavor nuances, but for those most concerned about mycotoxins, this can be a beneficial trade-off.

Brewing Method's Role in Mycotoxin Reduction

The brewing process itself provides another layer of protection. A Spanish study on ochratoxin A (OTA) found that the method of coffee preparation plays a significant role in reducing a consumer's exposure. The espresso machine's high pressure and short contact time with the coffee grounds are particularly effective.


Brewing Method	Estimated OTA Reduction	Key Factors
Espresso	~50%	High pressure, short brew time, and high temperature.
Moka Pot	~32%	Medium pressure and heat.
Auto-Drip	~15%	Lower extraction rate and longer water contact time.
Instant Coffee	Lower	The processing used for instant coffee can lead to higher mycotoxin concentrations in the final product.

As the table shows, brewing with an espresso maker results in a final beverage with a lower concentration of mycotoxins compared to other common methods. This is due to the rapid, efficient extraction that leaves more compounds behind in the used grounds.

How to Minimize Mycotoxin Risk in Your Espresso

For consumers, especially those with heightened sensitivity, there are several practical steps to further reduce mycotoxin exposure from espresso:

Choose high-altitude Arabica beans: Higher altitudes are less hospitable to mold growth. Combining this with the fact that most specialty-grade beans are Arabica, you significantly lower your risk.
Opt for wet-processed beans: The wet processing method is more effective at washing away mold spores from the coffee cherries than the dry process.
Buy from reputable roasters: Companies that specialize in high-quality, specialty-grade coffee often have stricter quality controls and faster inventory turnover, which minimizes the risk of mold growth during storage. Some brands, like Purity Coffee or Lifeboost, also provide third-party testing results.
Properly store your beans: After purchase, store your whole beans in an airtight container in a cool, dry place to prevent moisture from causing mold growth.
Grind your own coffee: Grinding beans increases the surface area exposed to air. Buying whole beans and grinding them just before brewing can help maintain freshness and reduce mold risk.
Avoid decaf and instant coffee (if concerned): Caffeine is a natural inhibitor of mold growth. Decaffeinated coffee is therefore more susceptible, and instant coffee often contains higher concentrations, though levels generally remain within safety limits.

Are "Mycotoxin-Free" Claims Legitimate?

Some brands market their coffee as "mold-free" or "mycotoxin-free," often at a premium price. The consensus among many coffee experts is that such marketing should be met with skepticism. Emma Sage of the Coffee Quality Institute notes that testing is required to confirm contamination and that the term "mycotoxin-free" is unregulated. Since trace amounts of mycotoxins are found in a wide variety of foods, and regulatory limits are already set at safe levels, paying a premium simply for the "mycotoxin-free" label may not be a worthwhile investment. The focus should be on selecting quality, specialty-grade beans from a roaster with transparent sourcing practices. More information on coffee quality control can be found at the Coffee Quality Institute.

Conclusion

The concern over mycotoxins in espresso is largely overblown due to modern processing standards and the nature of the brewing method itself. While mycotoxins are naturally occurring and can exist in coffee beans, the combination of high-quality sourcing, effective wet processing, high-temperature roasting, and the espresso brewing process work together to drastically reduce the levels to a point considered safe by international health organizations. Consumers who take a few simple steps, like choosing specialty-grade beans and proper storage, can enjoy their espresso with confidence, knowing the health risks are minimal and far outweighed by the benefits of a quality cup of coffee.

A Simple Guide to Reducing Mycotoxin Risk

Select Quality Beans: Opt for specialty-grade Arabica coffee from reputable roasters.
Choose Wet-Processed: Look for beans processed using the 'wet' method to minimize mold exposure.
Prefer Darker Roasts: If highly sensitive, a darker roast level offers higher thermal degradation of mycotoxins.
Store Properly: Use an airtight container and store in a cool, dry, and dark place.
Grind at Home: Grind whole beans just before brewing for maximum freshness and safety.
Use Espresso Method: The high-pressure, quick-brewing method is highly effective at reducing mycotoxin extraction.
Be Skeptical of Marketing: Don't overpay for unregulated "mycotoxin-free" claims. Focus on verifiable quality and process.

Frequently Asked Questions

At high levels, certain mycotoxins like Ochratoxin A (OTA) and Aflatoxin B1 can be harmful, potentially affecting the kidneys and liver. However, the levels found in properly processed commercial coffee are so low that they are considered safe for human consumption by regulatory bodies.

Yes. Arabica beans grown at higher altitudes and processed using the 'wet' method are less likely to contain mycotoxins compared to lower-quality Robusta beans or those from less controlled processing.

Studies have shown that brewing with an espresso machine results in a greater reduction of mycotoxins, specifically Ochratoxin A, than brewing methods with longer water contact times, such as auto-drip.

The only way to confirm mycotoxin presence and levels is through laboratory testing. As a consumer, your best approach is to choose reputable brands that follow strict quality control standards, or brands that share third-party test results.

For most people, paying a premium for coffee marketed as 'mycotoxin-free' is unnecessary. Reputable specialty coffee already has low levels well within safety limits. The term is often a marketing tactic, and the best defense is choosing high-quality, properly sourced and roasted beans.

Caffeine is a natural inhibitor of mold growth. This is why decaffeinated coffee may have slightly higher mycotoxin levels, though these are still typically well below safety thresholds.

Store your beans in a cool, dry, and dark place in an airtight container to prevent moisture exposure. Humidity and high temperatures are the primary factors that encourage mold growth.