Mold In French Press Filter: How To Clean And Prevent

Discovering mold growing in the filter or anywhere within your French press is a frustrating and sometimes gross experience. So if you’ve come to this article, I take it you are wondering what the most effective way of cleaning it is.

To clean a moldy French press coffee filter, pour 1 cup of white vinegar into the French press and push the plunger down, covering it in the vinegar. Leave to sit for 10 minutes to kill the mold, then pour away the vinegar and wash with warm soapy water. Scrub the filter with a toothbrush if needed.

In this article, I’ll be thoroughly explaining how to clean your French press of mold step-by-step, so keep reading.

Mold in french press machine how to clean

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Moldy Coffee And Mycotoxins: Do You Need To Worry?

How to clean a moldy French Press Filter

In many cases, the filter part of a French Press coffee maker is the most likely part to find mold growing on, as small particles of coffee grounds can easily get stuck in the mesh.

In order to be certain the mold is dead and fully removed, you can use the following steps:

Step 1. Measure 1 cup of white distilled vinegar and pour it into the beaker.

Step 2. Push the plunger down with the filter still attached so that it is fully covered in the vinegar.

Step 3. Leave the filter to sit in the vinegar for ten minutes. This will be plenty of time for the Vinegar to kill the mold.

Step 4. Pour away the vinegar and wash all the components with warm soapy water. Use an old toothbrush or soft-bristled brush to clean the filter if needed.

Step 5. Ensure the French Press is fully dry before storing it away. Any residual smell of vinegar will disappear in a few days.

How to remove mold from a French Press (deep clean methods)

There are two quick and easy tips to deep clean a moldy French Press that removes and kills the mold along with any of its spores.

You can use either white distilled vinegarOpens in a new tab. or baking soda, and for a really infested coffee maker, you can even use a mixture of the two.

The great thing about using vinegar or baking soda is that they are cheap, highly effective, and environmentally friendly. I often don’t recommend using bleachOpens in a new tab. or any harsh chemicals to clean mold out of any vessel that is meant to contain food or drink, as even the smallest residue left behind could cause serious harm to anyone who ingests it.

Vinegar method

To use vinegar to clean mold from a French Press, use the following steps:

Step 1. Make a solution of 1 cup of distilled vinegar to 1 cup of water.

Step 2. Pour the solution into a spray bottle.

Step 3. Disassemble the French Press as much as possible.

Step 4. Liberally spray the components (including the pot itself) with the vinegar solution and leave them to sit for ten minutes.

Step 5. Wash the components with warm soapy water.

Step 6. Ensure every part of the French Press is completely dry before reassembling and putting it away.

Baking powder method

To use baking soda to clean mold from a French Press, use the following steps:

Step 1. Make a solution of one tablespoon of baking soda to two cups of water and pour it into a spray bottle.

Step 2. Disassemble the French Press machine.

Step 3. Liberally spray the baking soda solution all over the components of the French Press.

Step 4. Leave until dry, this can take between ten minutes to an hour depending on the heat of the room you are in.

Step 5. Rinse under a cold tap to remove any residue, and store away when fully dry.

Is Mold In A French Press Safe To Use?

You may think that because you will be pouring boiling water into the French press it would kill the mold and any bacteria within it, and whilst it is true that some strains would be killed by such high temperatures, it would be very difficult to make sure that all of it was dead, mycotoxins that fungi release as a defense mechanism can also withstand very high temperaturesOpens in a new tab. and would not be killed by the water. This means that you could end up still drinking a portion of toxins along with your morning cup.

Inhaling or ingesting mold toxins or its spores can cause a myriad of health complaints, so it really is not worth taking the risk. Instead, ensure the filter and any other parts are completely cleaned before use, or if the growth is too substantial or has been growing for too long, it may be worthwhile investing in a new set.

Finally, when fungi grow, they often create a foul, musty odorOpens in a new tab. and bitter taste to anything added to it, so there would be very little enjoyment to come from any coffee made in a moldy French press.

For further detail on some of the health complaints that can be caused by drinking from a moldy French press, read on.

Can you get sick from mold on a French Press?

If you are either allergic to or susceptible to mold or its spores, you could become IllOpens in a new tab. from using a coffee maker that has mold in it.

Many mold strains are entirely harmless, however, some can produce metabolites called mycotoxins as a defense mechanism whenever they feel threatened or have been disturbed in any way.

If ingested or inhaled in small amounts, these mycotoxins would cause little concern unless you were very allergic to them, but in larger amounts or if ingested or inhaled over a prolonged period, they have the potential to cause any of the below symptoms:

  • Headache
  • Nausea
  • Vomiting
  • Gastrointestinal discomfort
  • Breathlessness

For these reasons, it is always suggested that you use the proper PPE (protective clothing) when dealing with any kind of mold yourself, such as a breathing mask, rubber gloves, and protective goggles. It may seem a little over the top to wear this kind of equipment when simply cleaning something that makes you coffee in the morning, but the dangers associated with mold can be very serious and should be treated as so.

Why do French Presses get moldy?

French Press coffee makers can become moldy for exactly the same reason that any other appliance can. As long as there are nutrients, and moisture and the temperature is correct, you can be certain that in only a matter of time, mold will begin to growOpens in a new tab..

Mold will find its nutrition from the old coffee grounds left behind after the previous use if not cleaned out properly, its moisture comes from leftover liquids from condensed steam trapped in the lid, or even the moisture in the air if in a humid climate, and, if left on a kitchen counter for the weekend in a warm temperature, you’ve given a colony of mold pretty much everything it needs to thrive.

What kind of mold grows in a French Press coffee maker?

There are several strains of mold that can be found growing in a French Press. The most common types are PenicilliumOpens in a new tab., Stachybotrys AtraOpens in a new tab., and CladosporiumOpens in a new tab.. You may also find a type of fungus called Trichoderma growing on any remaining coffee grounds.

The color of these molds can vary from white, black, grey, blue, green, red, and sometimes orange, with the textures often described as being powdery, velvety, or slimy. They often start life as small patches of white growth in a circular pattern that spreads over time.

How to prevent mold growing on a French press

The best way to prevent mold from growing in a French Press coffee maker is to clean it thoroughly after each use and make sure it is completely dry before returning it to a cupboard.

Mold cannot grow if it doesn’t have what it needs, so washing your French Press to remove any traces of coffee groundsOpens in a new tab. and then drying it fully will take away both the nutrients and moisture levels that mold needs to live.

Keeping a used French press sitting on the kitchen counter over the weekend will certainly be long enough for mold to begin to form, so if you want to avoid this, it needs to be cleaned as soon as you are done with it.

What is the black residue in my French Press?

After using a French press coffee maker, you may have noticed that there was a black residue or sludge left behind. The good news is that this is unlikely to be mold or anything dangerous. Instead, it is made up of natural oils from within the coffee that are released when the grounds are pressed and the majority of the moisture is removed. Any kind of black mold would have a slimy texture and grow in small clusters. There would also be a musty smell, rather than the pleasant smell of freshly brewed coffee.


French Press coffee makers are just as susceptible to mold growth as any other appliance if you do not follow simple rules to prevent it.

As long as you clean it after use and keep it dry, mold will not be able to grow, but should you find yourself in a situation where it was used and forgotten about, you can use the cleaning methods above to reclaim your French Press for another day. The types of mold that can grow in any coffee maker have the potential to cause sickness and the potential to be very dangerous to certain people, ensure you are wearing the correct safety equipment before starting to clean your coffee maker.

Over to you

I hope this article has given you some guidance on how to clean a moldy coffee filter from a French press, and I also hope you’ve learned a little about how to prevent it from happening again, but now I’d like to turn things over to you. Have you ever drunk coffee that came from a moldy French press? Do you have any extra tips that didn’t quite make it into this article? If so, I’d love to hear your stories and suggestions in the comment section below 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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