Mold In Coffee: Should You Worry About Mycotoxins?

So, should you be concerned about the rumors you have heard about coffee containing mold and the negative effects it can have on you?

Mold can grow in coffee beans, and some strains can produce a substance called mycotoxins that can be harmful to human health. However, the amount that would grow would be too small to cause harm, and any growth during the growing process would be killed as the beans were roasted.

In this article, we will be uncovering the truth about mold in coffee, how it gets into your cup in the first place, what effects it can have on the body, and whether you really need to be worrying in the first place. So, for the full run down on mold in coffee, keep reading.

Coffee mold

Does coffee have mold?

First things first, yes, some coffees do contain mold strains, and some of these strains can be potentially harmful to the body. However, what’s important to know here is that in most cases, you will rarely ingest enough of the mold and it’s mycotoxins (more on this later) to have a negative impact on your health.

One of the main reasons you may be more aware of mold in coffee is largely down to marketing ploys by high-end coffee brands stating that their particular beans are “mold-free”, insinuating that other brands have high levels of mold as standard.

This is simply not true, and as you will see throughout this article, despite some brands having trace amounts of mold in their coffee, the levels fall well within what is considered safe to consume by the Food and Drug Administration.

Why is there mold in coffee?

Mold is a living substance that can be found anywhere that is moist, has a consistent temperature, and has little sunlight. This is exactly the kind of environment that is provided when coffee cherries are picked and left to dry.

Green coffee cherries are picked and left to dry before roasting, the outer green layer of the cherry has a high moisture level, and if not dried quickly enough and stored in a dark place, will quickly begin to develop mold.

There is even the possibility that mold could have begun to grow on the coffee plant itself before the cherries were even picked. If this is the case, the potential for mold spores to have traveled from the plant to the cherry during processing is possible and could lead to the growth of new molds whilst in storage.

Can moldy coffee make you sick?

Coffee is full of health benefitsOpens in a new tab., from potentially lowering the risk of diabetes, supporting brain health, aiding in weight management, supporting heart health, and more.

Mold (or at least traces of mold), however, can be found in most coffees, so can it make you sick and undo the health benefits you would normally gain?

The main symptomsOpens in a new tab. associated with drinking mold found within coffee are:

  • Stomach problems
  • Coughing
  • Sneezing
  • Shortness of breath
  • Nausea
  • Runny nose/eyes

As you may have noticed, many of these symptoms can be associated with drinking coffee in the first place if you are not used to it, and with the quantities of mold and mycotoxins found in coffee, you’d have to drink a large number of cups in a day to reach the levels of mycotoxins that would actually cause symptoms.

So, drinking coffee with mold is unlikely to make you ill unless you are drinking vast quantities of it in a single day.

What are mycotoxins in coffee?

MycotoxinsOpens in a new tab. are toxins produced by mold spores found in both the Penicillium and Aspergillus mold strains. The two most common mycotoxins produced by these strains are Ochratoxin A and Aflatoxin B1.

These toxins have the potential to cause physical illnesses if consumed in high enough quantities.

Both the above-mentioned mycotoxins have been proven to be carcinogenicOpens in a new tab., with Aflatoxin B1 being the more damaging of the two as far as studies have so far shown.

Whilst this may sound distressing, because of intensive monitoring by the growers, producers, and food and drink administration, the quantities of mycotoxins found in most coffee and coffee blends are so little that you would need to drink high quantities of coffee to see any negative effect as a direct result of mycotoxin ingestion.

Do you need to worry about your coffee being “moldy”?

No, coffee producers are bound by strict rulesOpens in a new tab. to ensure the coffee they sell has only trace amounts of mold, in minute quantities.

Much as you may have heard about mold in coffee causing illnesses, the likelihood of these being caused by mold in your coffee is extremely low.

Even if mold were to be present on or within the beans before they were roasted, the roasting process has been shown to lower the amount of mold and mycotoxins by up to 93%Opens in a new tab. in light-roasted beans and up to 99% in dark-roasted varieties.

What if you accidentally drank moldy coffee?

The good news is if you were to find out that the coffee you have been drinking had mold growing in it, there would be very little to be concerned about as mentioned above. If you were severely allergic to moldOpens in a new tab. or its spores, it’s likely that you would notice symptoms fairly quickly, things like breathlessness, coughing, nausea, itchy throat, and any other manner of allergic reactions, but this is rare.

In most cases, you would have probably consumed very little mold, which for most people would not result in symptoms presenting. Of course, if you were to start to feel nauseous, or see any other symptoms you believe are related to drinking the coffee, you should seek medical advice just in case.

If you don’t see any immediate symptoms but are still concerned, you should monitor yourself for the next few days to see how you feel. Once again, if any unfamiliar symptoms appear, you can talk to a medical professional.

The additional factor here is that if you were to have coffee with mold levels high enough to cause harm, you would certainly be aware of it. The coffee would have a musty and unpleasant smell instead of the characteristic aromas you would expect, and a sour, bitter, or rancid taste that would instantly tell you to stop drinking.

How do you get rid of mold and fungus in coffee?

If you find that there is mold already growing in your coffee, there is very little you can do to save the batch. Even if you were to scrape off the top layer of mold, you would inadvertently be pressing some of the fungi and its spores deeper down into the granules or beans, which you would then end up consuming at a later date.

The safest and best option is to simply throw away the coffee that has mold growing on or within it and buy a fresh batch.

Why does my coffee taste moldy?

The most likely cause of your coffee having a moldy taste and musty smell is that it has been stored incorrectly.

Coffee producers (even the cheaper brands) have to comply with strict regulations and quality guidelines to ensure the coffee they sell is safe to consumeOpens in a new tab., so it’s unlikely the mold problem stemmed from a poor producer.

Many people store their coffee in perfect conditions to promote mold growth. These include:

  • A dark place with little movement of air
  • Humidity levels over 60Opens in a new tab.%
  • Temperatures between 77-86 FahrenheitOpens in a new tab.

If you’re storing your coffee in a cupboard or shelf in a kitchen, you are likely to see mold form on it at some point. The moisture and temperature levels of a kitchen are perfect for mold to grow. This means how you store your coffee is vital to preventing that moldy taste from occurring.

To prevent this, make sure your coffee is stored in a container that can be shut tight, rather than an open bag. Do not store your coffee in the fridge, as they are very humid environments, and try to make sure it is in the driest place in your kitchen, away from the cooker, kettles microwaves, and any other appliances that can create steam.

Does instant coffee go moldy?

Instant coffee in individual packets should remain free of mold for several months as long as it is stored correctly, however, it can begin to lose its flavor within a few months. Instant coffee has a much longer shelf life than freshly roasted beans, but if stored in moist environments and not in a sealed packet such as a jar on a kitchen counter, instant coffee can grow moldOpens in a new tab. just as easily as fresh beans.

How long does it take for mold to grow in coffee?

Mold can begin to form very quickly if the correct environment is provided. Should coffee powder or grounds become moist or be stored in an area with a humidity level in excess of 60%, and a temperature of between 60-80 degrees Fahrenheit, mold can begin to develop within 24-48 hoursOpens in a new tab..

There are a number of additional factors that can speed up or slow down the rate at which it can grow, these include, the amount of airflow around the beans, the pH level of the coffee, and the amount of light it is exposed to.


Without airflow, stale, moisture-laden air can build in humidity to the point where water droplets can condense and become a source of hydration for mold. When natural airflow is introduced, it replaces the stale air with fresh, dry air, keeping overall humidity and moisture levels low.

pH levels

The acidity of the coffee you have purchased can play a big part in the rate at which mold can grow in it, as some strains prefer to grow in slightly acidic environments, while others prefer neutral to slightly acidic environments. For example, African and Central American beansOpens in a new tab. tend to have higher acidity levels, and variations of strains such as Penicillium, Aspergillus, and Mucor can all quickly grow in the environment they provide.

Light exposure

The sun’s UV rays have anti-microbial and anti-fungal propertiesOpens in a new tab., which can slow down the rate at which mold can grow when it is exposed to them, in some cases it can even damage the very DNAOpens in a new tab. of the fungi, reducing its ability to reproduce and spread.

Whilst some strains prefer to grow in the dark because of this, there are others that can happily grow in sunlight, but this is less often the case, therefore the amount of natural sunlight your beans are exposed to can play a big part in how quickly mold can grow on or around them.

It’s important to note that placing your coffee beans in direct sunlight to prevent mold growth is not recommended, as light exposure can speed up oxidization and spoil the beans and their delicate flavor profiles.

Does decaf coffee have more mold than standard coffee?

Removing the chemical trimethylxanthine (caffeine), not only removes the naturally occurring stimulant effect of coffee but also reduces the bean’s ability to protect itself against molds and bacteria. Caffeine works as a natural fungicide, making it much less likely to become infected with mold. As a result of this, decaffeinated coffee is more likely to grow mold than standard.

Having said this, as long as the coffee is stored correctly, kept away from moisture sources in an airtight jar, and is used within the expiration date written on the jar or tin you purchased it in, it should still last for a considerable time.

Does organic coffee have mold?

Organic coffee is affected by mold in the same way as non-organic. The difference between organic and non-organic coffee is that organic is grown without any additional chemicals or pesticides. The fact that it is certified organic will make no difference as to whether or not it will grow mold.

Organic and non-organic coffee beans are processed in the same way after processing, so whether or not they contain mold is purely down to the height the beans are grown, and the environment they are stored in before being roasted.


Coffee can indeed contain mold. However, you have very little to worry about if you store your coffee correctly in a dry location. Coffee bought straight from the store and kept under the correct circumstances will contain only trace amounts of mold, not enough to cause any health concerns.

Over to you

I hope this article has given you some guidance about the presence of mold and mycotoxins within your coffee and whether you actually need to worry about it. Now I’d like to turn things over to you. Have you ever drank moldy coffee? Or do you have any additional storage tips you swear by to keep your coffee fresh?

If you do, I’d love to hear about them in the comments below, or if you have any questions about anything in the article, just let me know and I’ll get back to you ASAP.

Chris Walker

Chris Walker has struggled for several years with mold after buying his own property. After finding the solutions to several issues around his home, he decided to create this site in order to answer as many questions about mold and mildew as possible to help others dealing with the same problems.

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