Can Tea Bags Get Moldy? Spot And Prevent Mold In Tea Bags

Tea bag collections tend to grow out of control rather quickly. Sooner or later you will have more tea than you can drink. Will the older tea bags grow mold? Do you need to throw them out?

The growth of mold is heavily dependent on the environment. If you store your tea bags properly, there should be minimal growth of mold on your tea. But when exactly is your tea in danger? How can you avoid mold?

SHORT ANSWER – Can Tea Bags Grow Mold

Yes, tea bags can grow mold. Mold will grow on most organic material with the right humidity, temperature, and airflow. With proper storage conditions, you can avoid the growth of mold indefinitely. Whether or not your tea bags have become moldy is easy to determine visually and by smell or taste.

So, tea bags can get moldy. But how exactly do you prevent the growth of mold on your tea bags? And how do you determine whether they already have grown mold or not? Let’s find out.

Can Properly Stored Tea Bags Get Moldy?

Properly stored tea bags should not be able to grow mold at all. On the packaging of all tea bags you will find the instructions to store them in a cool and dry environment. The reason for this is partially the prevention of mold growth.

When Can Tea Bags Grow Mold

Mold requires three things to grow. Without any of these three things, you will never have any mold on your tea bags. You need to have the right temperature, humidity, and some airflow to grow any mold.


The growth of mold requires temperatures between 32 °F (0 °C) and 120 °F (49 °C). The optimal temperature for mold growth is somewhere around 80 °F (27 °C) but mold can thrive anywhere in the given temperature range.

 Any temperature above or below this will prevent the growth of mold. That is why food stored below the freezing point will not ever get moldy. The same goes for tea. But who stores their tea in the freezer? I don’t.


The most easy factor for you to control is the humidity of your tea bag storage container. The risk of moldy tea bags rises with humidity levels above 60-65% (relative humidity). Above 70-75% you will have a very high risk for mold growth, as droplets of water can form on the tea itself.

While you do not want to store your tea with too high humidity, be careful not to dry out your tea completely either. The tea will not go bad anytime soon, but lose most of its flavor due to the dryness.

I would recommend storing your tea bags in a room or storage container that has humidity levels anywhere between 50% and 65%. These levels are a compromise between the longevity of your tea bags and the preservation of the taste of your tea.


Just like people do, mold requires air to live and reproduce. Without air, mold will die sooner or later. The only thing that may be left could be tiny amounts of spores. Without air, there is no mold growth at all.

Tea that is stored under a vacuum or a nitrogen atmosphere will therefore not grow mold or go bad. The tea will be good for many years. Furthermore, tea that is stored without air contact will keep its flavors for much longer.

How To Know When You Should Throw Out Your Tea Bags

Now, you may have some tea bags that have been lying around for quite a while. You are not sure whether these tea bags are good to use, have grown mold or gone bad in another way? Here are 3 things that you should keep an eye on.

Moldy Tea Bags

You were looking for information on tea bags getting moldy, so obviously you would need to check for mold on your tea bags. There are a few obvious signs for the growth of mold that you can quickly notice on your tea collection.

Look at your tea bags. Are there any signs of mold on the paper (or plastic) bag or the paper tag? If so, the tea has significant growth of mold, as the mold grows outward from the tea to the bag itself.

You will have a hard time looking at the tea itself. But there is a quick and easy test for mold you can do. If you take the tea bag and let the tea slide up and down physically within the tea bag, are the leaf pieces moving as a single piece or lump?

If so, you have mold in your tea bag that has formed mycelium throughout the tea leaves. If the broken leaves are moving individually like they would with a newly purchased tea bag, mold is unlikely to have formed in your tea.

Smell your tea bags. Our sense of smell has developed and perfected itself over many generations. By smelling tea or other food, you can notice any off-taste that indicates harmful mold in your tea.

If the tea smells weird in any way, you should throw it out immediately. Weird and disgusting smells will always indicate some form of microorganism or poisonous compound in your tea.

Other Microorganisms

For one, you can easily smell other microorganisms, too. Bacteria will have an acidic smell and yeast also has a characteristic awful smell to it. Smelling is the easiest and most reliable way to sense if anything is wrong with your tea bags.

Furthermore, the growth of bacteria will leave your tea bag looking and feeling wet. Bacteria tend to flourish in liquid water, often discoloring the tea bag. A wet, brownish tea bag with awful smell should never be used for tea brewing. But nobody would use those anyway!

Noticeable Off-Taste

Imagine that you have not been able to determine anything wrong with your tea bags. You have decided to brew this tea you bought years ago that still looks and smells fine. The resulting brew looks and smells good, too.

Then, as you are tasting the tea, you notice that the taste is somewhat off. You remember the tea differently and you are sure that this weird taste is not supposed to be there. But the tea must be good, you have checked it beforehand?

In small amounts, both bacteria and mold will not be visible and may sometimes give off too little smell to be noticed. If you notice unusual and unwanted flavors in your tea, you should be careful. If you are not sure whether the tea could have gone bad or not, you should always be safe and throw it out.

There’s a lot more to learn about tea! If you are looking for a good place to start, I highly recommend the book Tea: History, Terroirs, Varieties. You can check its current price on Amazon here.