Eat Chocolate in the Name of Science!
Try this simple experiment
- Break off two squares of a chocolate bar. Wrap each square in foil. Place one square in the freezer for a few hours and leave the other at room temperature.
- Unwrap the room temperature square and place it on your tongue. How fast does the chocolate melt? How long does it take to taste the chocolate flavor?
- Take a few sips of water or bites of an apple or saltine cracker to cleanse your palate.
- Unwrap the square from the freezer and place it on your tongue. Is the experience the same as the room-temperature square?
- Predict what would happen if you did the experiment again, but grated each square into small shavings first. Try it!
Why is it important to have a melting point close to body temperature?
Because the speed at which chocolate melts in your mouth affects its flavor!
This short experiment is based on “Project 15: Viscosity and Flavour” from The Science of Chocolate, 2nd ed., by Stephen T. Beckett.
The author explains "...the speed at which a food melts in the mouth affects its taste as well as its texture. This is because the chocolate viscosity affects the speeds at which the different molecules reach the flavor receptors."
Students should notice a difference between the taste and texture of the room-temperature and frozen chocolate because the frozen chocolate must first be warmed up in the mouth before it melts, while the room-temperature chocolate quickly melts in the mouth. The difference in taste and texture of the frozen grated chocolate should be less because although it is still frozen, it melts more quickly on the tongue than a solid piece of frozen chocolate.
Since palmitic acid has a melting point of 63°C (145°F) and stearic acid has a melting point of 70°C (158°F), the differences in the melting temperatures of the six β forms of chocolate falls heavily on the amount of unsaturated oleic acid present, which has a melting point of 16°C (61°F).