Does oobleck go bad?

In this brief article, we will answer the question, “does oobleck go bad?” and discuss the shelf life of oobleck, how to know if oobleck has gone bad and the risks of consuming spoiled oobleck. 

Does oobleck go bad?

Yes, oobleck can go bad, dry out, and even rot, and usually remain its best for just about a day. However, this will depend on its storage conditions.

Oobleck is mainly composed of starch and water and has a high moisture content. In general, high moisture food products are susceptible to microbial growth and should be kept refrigerated for a limited time (1,3).

Cornstarch and other types of starch can naturally carry fungal spores, yeasts and other microorganisms, which develop when conditions are favorable, such as increased availability of water and favorable temperatures (1,3,5).

In addition, during storage, the texture of the oobleck changes considerably. Oobleck is a cornstarch dough and therefore undergoes a process called retrogradation, in which the starch chains are reorganized, losing their initial structure. As a consequence, syneresis occurs, expelling water from the dough (3).

How to know if oobleck has gone bad?

To know if oobleck has gone bad, look for signs of possible indications of spoilage, which include (1,3,5):

  • changes in the texture: dryness, exudation, increased hardness, slimy, rot texture
  • presence of off-odors: odors such as sour, moldy, musty, fermented
  • mold growth: colored spots, growth of mycelia on the surface (coton-like structures)
  • formation of slime on the surface 

Is it dangerous to consume spoiled oobleck?

Yes, it is dangerous to consume spoiled oobleck. Even though it is not life-threatening to consume spoiled or ‘bad’ oobleck,  it can result in stomach discomfort and intestinal pain, even if not ingested. 

By handling the oobleck and not washing the hands, and bringing the hands to the mouth or eyes, there is a risk. That is because it can contain microorganisms or toxins produced by microorganisms, which are toxic if in contact with the mucosa or inhaled (1,5). 

On the other hand, if color paint was added to the oobleck, it can cause intoxication due to the presence of heavy metals. Symptoms can include hives, itching, flushing, swelling, sneezing, runny nose, cough, wheezing, shortness of breath and nausea (2).

Can you store oobleck?

Yes, you can store oobleck, although you should not store oobleck, as stated by Chemistry Professors from the Duke University in Canada. Oobleck can be spoiled by molds, which makes its storage unsafe (4).

However, if the oobleck will be used on the same day, or even on the next day, it is possible to store ir. For this, it should be stored in an airtight, tightly sealed container and ideally placed in the fridge. It is preferred that you put the container of oobleck on the top shelf since this is the coldest area of the fridge (4).

How do you make oobleck?

Here’s what you need to make a batch of oobleck (4):

  • Two cups of cornstarch/ cassava starch 
  • One cup of water
  • Food coloring (Optional)
  1. Mix the cornstarch and water in a large bowl. Keep mixing until you achieve your desired consistency. If you want to add color, mix the food color and water before you add the cornflour. 
  2. If the mixture seems too watery and isn’t forming into a solid oobleck, add some more cornstarch. Alternatively, if the oobleck seems too hard and inflexible, aad some more water. Remember: the key to perfect consistency is experimenting.


In this brief article, we answered the question, “does oobleck go bad?” and discussed the shelf life of oobleck, how to know if oobleck has gone bad and the risks of consuming spoiled oobleck.

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Rahman, M. Shafiur, ed. Handbook of food preservation. CRC press, 2007. 


Martin, Sabine, and Wendy Griswold. Human health effects of heavy metals. Environ Sci Technol briefs cit, 2009, 15, 1-6.  


Kilcast, David, and Persis Subramaniam, eds. The stability and shelf-life of food. 2000.


Greenhill, Andrew R. Food safety and security of sago starch in rural Papua New Guinea. Diss. James Cook University, 2006.