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Mold in Coffee: Facts, Myths, and How to Avoid It

Mold in Coffee: Facts, Myths, and How to Avoid It

Clark Clark
8 minute read

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The last thing you want to think is, could there be mold in mycup of coffee?We typically laud coffee for its health benefits; it’s a great source of antioxidants and is potentially anti-inflammatory

However, mold toxins have become a concern for many consumers. Coffee consumption shouldn’t generally make your heath worse, but the levels of mycotoxins (mold toxins) in your coffee could cause some harm.

Is there really mold in coffee? Mold can develop in/on coffee beans; however, the mold itself is not as harmful as its byproducts — mycotoxins. Not only can they be found in coffee beans, but also in cereals, nuts, dried fruits, and spices.

The Food and Drug Administration warns that mycotoxins can cause health problems such as neurologic impairment, liver damage, kidney damage, or heart failure.

But let’s be clear: The levels of mold in coffee are almost never going to be high enough to cause major harm. It’s a myth that most coffee is full of harmful levels of mold spores.

Let’s break down the facts.

Why is there mold in coffee?

Mold spores are fairly difficult to trace, so it’s hard to pinpoint exactly where they get in the coffee. Though there are plenty of opportunities for mold to grow, this doesn’t mean that it always does. 

Several factors contribute to moldy coffee:

  • Climate: Mold tends to grow in warm, moist conditions. Since the Bean Beltis primarily tropical, coffee is at a mold risk from the get-go.
  • Acidity: Mold doesn’t mind a high pH and can thrive in places bacteria tend to avoid. (Low-acidcoffee might be an excellent alternative.)
  • Growth conditions: Mold could be present in the soil coffee beans are grown in. 
  • Processing: Mold can grow on green coffee beans if they go through wet processing and are not dried properly. It could flourish on green coffee beans that go through dry processing because the bean remains with its moist outer layers for a longer period. Mold can also creep in during the fermentation process.
  • Storage time: The longer beans remain in storage, the more likely they will grow mold.

But surely mold can’t survive the roasting process, right? In reality, roasting can help get rid of mold but not entirely eliminate it. If roasting machines aren’t properly and regularly cleaned, mold can get into roasted coffee and subsequently brewed coffee.

Is coffee mold harmful? Trace amounts of coffee mold are not considered harmful, according to a 2015 study. However, heavy exposure over a long period can cause serious health issues. 

What is the mold in coffee?

The mold in coffee typically includes themycotoxinsochratoxin A andaflatoxin B1.

Mold is a multicellular fungus. Like any other fungus, it’s known for its role in decomposition. This is why keeping an eye out for mold matters — mold signals spoilage due to decay. Mold metabolites (the result of mold’s metabolism process) are called mycotoxins.

There are several hundred types of mycotoxins. Only a handful are harmful to humans if ingested. These include fumonisin, patulin, zearalenone, ochratoxin A, and aflatoxin B1. 

The two most notorious foodborne mycotoxins are ochratoxin A and aflatoxin B1, both of which are produced by a specific type of mold, aspergillus. Both are considered carcinogens.

Ochratoxin A (OTA) has been linked to kidney damage, immune system suppression, and liver cancer

The World Health Organization considers aflatoxin B1 among the most poisonous foodborne toxins. It has been linked to liver cancer and DNA damage.

What is coffee mold called? Coffee mold is just called coffee mold. When people discuss the harmful mold specific to coffee, they are usually referring to the mycotoxins produced by mold.

Health Risks of Drinking Moldy Coffee

TL;DR — Exposure to tiny amounts of mold in coffee is common and not associated with significant health risks. But if you’re drinking coffee with significant mold content, it may causeside effects.

Long-term risks of mycotoxins have been established. But ingesting coffee mold can cause some possible short-term symptoms.

What happens if you drink moldy coffee? Drinking moldy coffee is unlikely to cause much harm. It’s not unusual to consume tiny amounts of mold in food. However, ingesting mold could cause a short-term reaction usually resolved within 24-36 hours.

For starters, the taste would likely be different. The coffee wouldn’t have the vibrant flavors you’d expect from a fresh brew. There might be an earthy or musty taste to it.

Taste aside, sometimes mold consumption can lead to side effects such as:

  • Upset stomach
  • Fatigue
  • Headaches
  • Brain fog
  • Respiratory issues (coughing, sneezing, runny nose)

While it’s good to be aware of these possible symptoms, it’s also worth knowing you may not experience any symptoms. One 2021 study indicates that the OTA levels in coffee are very low-risk.

How to Avoid Coffee Mold

Trace amounts of coffee mold are difficult to avoid. But there are some ways to increase the likelihood of mold-free coffee.

To avoid coffee mold:

  • Purchase high quality, organic coffee beans
  • Clean your coffee maker regularly and disinfect frequently, especially if you see evidence of mold growth
  • Properly store coffee beans or coffee grounds
  • Visually examine coffee before brewing
  • Drink regular coffee as opposed to decaf coffee (caffeine is a natural mold deterrent)
  • Be wary of coffee blends and instant coffee (cheap types of coffee are more likely to contain mold)
  • Look for a lab certification on the label

How do you make coffee without mold? To make coffee without mold, purchase the highest quality coffee, stow it carefully, and brew it near the purchase date. Some coffee brands boast mycotoxin-free coffee, which could be worth researching.

Coffee mold could be more prevalent than we’d like to think. One study showed that 45% of commercial coffee beans contain OTA. This sobering study might make us want to monitor our morning cup a bit more carefully. 

Getting Rid of Mold in Coffee

You know coffee beans have developed mold if they have a coating of white fuzz. You can also detect mold if the coffee beans have different textures, smells, or tastes. It is worth noting that mold growth is not always detectable.

If your coffee has become moldy, the best thing you can do is throw it out. However, if you really want to save to beans, there’s a way.

What is the best way to clean mold from coffee? 

  1. Rinse the moldy coffee beans in cool water.
  2. Use a blunt knife to cut away mold that didn’t wash off.
  3. Fill an airtight container with 2 parts water and 1 part vinegar.
  4. Pour beans in solution, cover the container, and wait for 30 minutes as the vinegar leeches mold from the coffee.
  5. Drain the solution and once again rinse the beans in cold water.

Though this process helps extract mold from coffee beans, it’s not necessarily foolproof in getting every bit of mold out. Also, the vinegar can alter the taste of the coffee.

Drink Better Coffee

One of the best ways to ensure low to no mycotoxins is to buy high-quality coffee beans. Organic, pesticide-free coffee is best. Also, look for brands whose coffee beans were grown in high altitudes, as this means a drier climate.

Golden Ratio is better coffee incarnate. Skip the mold, bitterness, and acidity of the other guys and try gold coffee today!


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  2. Effect of roasting conditions on reduction of ochratoxin a in coffee
  3. Analysis of mycotoxins in coffee and risk assessment in Spanish adolescents and adults
  4. Ochratoxin A and human health risk: A review of the evidence
  5. Ochratoxin A - an overview | ScienceDirect Topics
  6. The occurrence of ochratoxin A in coffee

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