Cooking a Potato

In this segment of Chemical Engineering in Cooking we are going to look at the science, in particular the chemical engineering, involved in cooking a potato. Baking a potato is an activity that most people have done at one time or another, but most people have not stopped to think why a potato cooks or what would make it cook faster. These concepts are based on the chemical engineering concept known as heat transfer.

Heat transfer is the phenomenon that allows heat to move through substances, such as a potato. Heat transfer is involved in many everyday events. When a pot of water is set on a stovetop, the stovetop transfers heat from the hot coils to the pot of water. You can notice that the pot of water becomes very hot to the touch. You should not touch the pot, or you will burn yourself, but if you touch the plastic handle, you will not burn yourself. That is because the plastic handle does not heat up as fast as the metal pot. Different substances transfer heat at different rates. Materials such as metals transfer heat well, while materials such as plastic transfer heat much slower. Frying pans are made of metal with plastic handles because it is safer to the consumer to grab a plastic handle instead of a metal handle. The concepts behind consumer safety, in this instance, are therefore chemical engineering concepts called heat transfer.

The same idea is used when cooking a potato. The potato has heat transfer properties that allow the heat in the oven to travel through the potato to the center. Therefore the center of the potato will cook instead of just the outer layer. Without such heat transfer properties, a baked potato would be soft on the outside and hard in the middle.

How then, would you compare the cooking time for a small potato to a large potato? See answer.

What then would you guess would happen if a nail was stuck into the middle of the potato? See answer.

Proceed to the example
Return to Heat Transfer

[Introduction | Kinetics | Heat Transfer | Mass Transfer | Bibliography]

This project was funded in part by the National Science Foundation and is advised by Dr. Masel and Dr. Blowers at the University of Illinois.

2007 Arizona Board of Regents for The University of Arizona