Does Oobleck Dry Out, Expire, Mold Or Rot?

Oobleck is a fun and interesting substance that can keep you and your children entertained for hours at a time. Oobleck is a great science experiment for older children, and it is a great tactile and fine motor stimulant for toddlers and babies to play within a messy play session. But can oobleck expire, dry out, grow mold, or rot?

Oobleck can defiantly expire, dry out, grow mold, and rot, as oobleck is made of food products and is therefore considered a food product itself. The best way to avoid these things from occurring is to store the oobleck correctly and only for about two weeks, after which it should be disposed of.

Making oobleck is an easy process that does not take too long to do, but there are some situations that call for the oobleck to be made ahead of time and stored. This is where the oobleck can dry out, grow mold, rot, or even expire if made too early. So how do you store oobleck correctly to ensure these do not happen? We will discuss this in this article. 

Can Oobleck Go Off Or Expire?

If stored properly, oobleck can actually last quite a long time, but as oobleck is considered to be a food product, it can go off or expire after a while. The length of time it takes for the oobleck to expire or go off will depend on your oobleck storage methods.

However, even if you store the oobleck correctly, there is a recommended amount of time where the oobleck is still considered “good,” after which it is highly recommended to dispose of the oobleck to ensure that you do not play with or accidentally ingest oobleck that could cause you some harm.

The dangers of consuming expired or off oobleck are not life-threatening, but it can cause some discomfort in the stomach and the intestines, which do tend to go away on their own in a few hours.

It is important and highly recommended to keep track of how long you have had the oobleck for, especially if you are giving it to toddlers to play with.

To help keep track of this, you can either write down the date the oobleck was made on the container you keep it in, or you can write its date down in a notebook that you can then keep close to the stored oobleck.

Can Oobleck Grow Mold?

As oobleck is technically a food product, it can grow mold, although this is most likely to occur if the oobleck is stored using improper storage methods and is kept this way for an extended period of time. If the oobleck is not stored correctly, then it can begin to grow mold after three or four days.

During this time of three to four days, it may not be safe to play with the oobleck as the mold spores are still present in the oobleck and are not visible to the human eye. These spores can also be dangerous to your health if they are ingested, so it is better to avoid this situation in its entirety and just store the oobleck correctly from the beginning.

Oobleck can also grow mold if kept for too long, even if proper storage methods were used. This is because, as mentioned earlier, oobleck is a food product, and all food products can grow mold after a certain time frame.

Although, if the oobleck is stored correctly, it significantly slows this process down, and it will take longer for the mold spores to develop and grow, making the oobleck safe to play with for longer.

Can Oobleck Dry Out?

Oobleck can dry out, but this is actually considered to be one of the perks of oobleck as it makes for an easy clean-up once all the fun is done. The oobleck will dry up after a few hours of being left in the air.

When the oobleck is all dried up, it will turn back into normal corn starch, which means that you can just vacuum it up or sweep it up from the surfaces that it is left on, which is an easy clean.

It is not recommended to use this corn starch that was once oobleck in any other way other than to make more oobleck as the corn starch may have picked up some germs during the initial oobleck play session that are not a good idea to consume. 

This is also only recommended if the person or child that will be playing with the re-hydrated oobleck will not be inclined to eat the oobleck; in other words, re-hydrated oobleck is not suited for babies or toddlers.

Can Oobleck Rot?

Oobleck can rot in very particular conditions; this means that it does not happen often, but it can still occur as, remember, oobleck is a food product. For oobleck to rot, it needs to be kept as oobleck; in other words, it can not be allowed to dry out.

This means that you need to keep adding in water to ensure that the oobleck is hydrated. Then you need to improperly store the oobleck in a cool, dry cupboard. After a few days in these conditions, the oobleck will begin to rot. To avoid this, you need to store oobleck correctly.

How To Correctly Store Or Dispose Of Oobleck

Storing oobleck correctly is quite easy to do; for this, you will need an airtight container big enough to hold your batch of oobleck, a fridge, a notebook and pen, a spoon, and some water.

Once the batch of oobleck has been made, place it into the airtight container and seal it properly. Then place the container containing the oobleck into the fridge, preferably on the top shelf of the fridge as this is known to be the coldest part in the fridge.

Then write done the date that the oobleck was made in the notebook and keep the notebook next to the fridge for easy access.

Then you need to mix in a little bit of water into the oobleck every day to ensure that the oobleck does not dry out. You can store your oobleck in this way for two weeks; after this time, it is recommended that you dispose of the oobleck.

To dispose of the oobleck, add in a good amount of water to make a slurry out of the oobleck. Then pour the slurry down the drain while the hot water tap is open. The hot water will help dissolve the corn starch in the slurry, ensuring that it does not clog your drain.


Oobleck can indeed go off, expire, dry out, grow mold, and rot, as oobleck is made out of food products and is therefore considered a food product itself. For this reason, it is best to store oobleck properly to ensure that you have “good” oobleck that will not harm your health and that you get the most out of your oobleck. Enjoy your oobleck play sessions!


Article checked by:
Dr Binu George – Consultant General Pediatric
(MBBS, FRCPCH, Dual CCST (UK), Paediatric Neurodisability)
Head Of Department, Child Development Department at
NMC Royal Hospital, Khalifa City, Abu Dhabi, United Arab Emirates

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