A guy referred to as the Crazy Russian Hacker uploaded an epic discovery in his YouTube channel to show curious minds, like his, on what happens next whenever you place marshmallows in a vacuum?
He’s not talking about the actual vacuum cleaner that is typically used to suction up dust and dirt from carpets but a vacuum sealer having a hand pump, which draws out the air off its container.
After putting four pieces of marshmallows inside the clear container, he pumps out a bunch of air from it. The marshmallows start to expand, maintaining their barrel-like shape. While he allows the air out, they start to wilt back down to dimension, looking somewhat deflated and wrinkled.
The marshmallows diminish much more, resembling cubed raisins as he lets more air out.
Sadly, he doesn’t seem to check and see how the wrinkled marshmallows hold up toasted over the fire or in a s’mores sandwich.
Marshmallows are made of sugar foam with plenty of small air pockets. Whenever you place the marshmallows in a container and take away the air inside the jar (creating a vacuum) the pressure within the container decreases and thus, the air molecules inside the marshmallows will expand.
This is because the air tries to get out of the air pockets and causes the marshmallow to get bigger. Once the vacuum-seal is broken the marshmallows may shrink again and air pushes back into the container.