Edible Holiday Slime

Last year, we learned how to make Christmas slime and it was so much fun! Who wouldn’t want to play with slime? And for many people, playing with something gets much more interesting when you know you can eat it afterwards. This week, we’ll be focusing on edible slime and how it is different from the varieties of slime that aren’t safe to ingest.

Previously, we’ve used some ingredients in slime that wouldn’t be safe - or enjoyable - to eat. Slimes made with non-toxic won’t cause any harm if you happen to eat a little, but it won’t taste very good! On the other hand, slimes made with laundry detergent and borax are definitely not safe to ingest and are toxic, especially for young children. Typical slime made with glue and starch is seen below!

​Most edible slimes will use condensed milk and cornstarch, which are ingredients that you can use for baking, so they are completely safe to eat and might just taste a little better too! The edible slime is still a polymer, so nothing too drastic has changed for you to be able to eat it. Polymers are a macromolecule (larger and more complex than a molecule) that has multiple parts, or monomers. When we talk about slime as a polymer, we mean that the different ingredients are bound together to become one ball of goo! For more about polymers, check out our previous blog about Christmas slime here.

Here, instead of polymer cross-linking reactions linking the molecules of glue and starch together, we get our slimy texture from the expansion of cornstarch granules in some hot liquid. As the starch granules expand, they absorb and trap the liquid, creating a gel-like consistency. In order to evenly mix all of the ingredients, we need to heat up the cornstarch so it thickens the mixture considerably. Adding heat to the cornstarch excites the molecules, making them more likely to bind with molecules of the condensed milk. Then, the starch expands and swells as it absorbs the liquid, giving you the perfect slimy texture!

Make Edible Slime!

Now that we know more about the science behind slime, let’s get to making our own! We know that most edible slimes use condensed milk and cornstarch as the main ingredients, and from there you can add any sort of flavoring you’d like, but in spirit of the holiday season here are two festive recipes to try out!

Chocolate Slime

You will need:
14 oz. can of sweetened and condensed milk
3 tbsp chocolate syrup
¼ cup cornstarch
Chocolate chips (optional mix-in)

Combine the milk, cornstarch, and chocolate syrup in a pot and bring to a boil, stirring frequently until the mixture has thickened considerably. Dust a cutting board with more cornstarch and pour out the slime in the pot onto it. You’ll want to give it a few minutes to cool down, and then you can start to knead the slime into the cornstarch. If the slime is still too thin after a few minutes of kneading, you can add a little more cornstarch. However, this slime will stay very sticky. If you’d like, you can add in a handful of chocolate chips to add to the texture of your slime!

Marshmallow Slime

You will need:
6 jumbo marshmallows
1 tbsp coconut oil (or any vegetable oil)
1 tbsp cornstarch

In a microwave safe bowl, combine the marshmallows and coconut oil. Microwave on high for about 30 seconds. Add half of the tablespoon of cornstarch to your bowl and mix it in with a spoon. Keep stirring until the slime cools down enough to start kneading and playing with it! You can add more cornstarch to make your slime stiffer and more like putty.

​The last step is to enjoy playing with your edible slime!