Roasted Marshmallows- by Gillian Willis.

  

Marshmallows contain a high percentage of sugar but also contain corn syrup, gelatine and corn starch. Roasting marshmallows is a fun and common practice especially around campsites although it can be done at home as well, using candles. Have you ever wondered about what actually happens when you roast a marshmallow? From my research, I will have a go at trying to explain!

When a marshmallow is placed near a flame it goes through a series of stages. As the marshmallow heats up the bonds that hold the sugar and oxygen atoms together begin to break and rearrange themselves forming water molecules and carbon dioxide gas.

As the water molecules turn to steam, the marshmallow begins to expand and tiny holes develop in the surface of the marshmallow for the steam to escape.

As the marshmallow depletes of moisture, it becomes a crispy char.  Oxygen in the air rushes to its surface and it begins to burn. A bluish flame is sometimes seen due to the carbon (from the sugar) reacting with oxygen.

  As it burns, the marshmallow goes through various colour changes. If left to burn over the fire the center will collapse and will also burn in available oxygen from the air. You will then end up with a black, residual mass of crispy char (carbonization of the sugar). Can you guess what this black mass really is??

So what’s your favourite type? Lightly toasted and golden brown? Black and charred on the outside yet gooey on the inside, or do you just prefer them straight out of the pack?

 

 

 

References:

google images

http://teachers.bsd405.org/dightmanb/biology/dailywork/unit1_part2_lesson4.pdf

Accessed: 25^th Feb. 2012

All Biochars are Not Created Equal, and How to Tell Them Apart. 2009

McLaughlin, H., Anderson, P., Shields, F., Reed, T.