Why Do You Need to Pierce Potatoes Before You Bake Them?

Close-up of potatoes stacked high on top of each other

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A baked potato is one of the easiest foods to prepare and can accompany a wide range of dinner menus. The one rule that you should always remember when baking potatoes is that you must pierce them with a fork before baking. The reason is that potatoes can explode in the oven if they are not properly pierced, resulting in a ruined dinner and a hard-to-clean mess. The reasons for this phenomenon are simple and follow basic scientific principles.

Scientific Explanation

All potatoes have skin that helps them retain the moisture inside. As a potato begins to heat up in the oven, steam is created from this moisture and begins to build up beneath the skin. Eventually, if the potato has not been pierced, the steam creates enough pressure on the skin that it breaks open suddenly, causing a messy explosion. While not all potatoes that haven't been pierced explode, piercing them eliminates this risk.

Proper Technique

When piercing a potato, the important thing is to insert the fork deep enough into the flesh to allow the steam to fully escape. Many cooks make the mistake of only piercing the skin superficially, resulting in a potato explosion. As a general rule, insert the fork about halfway into the potato and pierce it three or four times.

Microwaving Potatoes

Potatoes baked in the microwave also run the risk of explosion if not pierced, according to the University of the District of Columbia. A microwave oven heats the potato by depositing energy in its water, and when this water begins to boil, the potato explodes just as it would in a standard oven. Be sure to poke holes in your potato if you decide to cook it in the microwave.

Safety and Cleanup

If you forget to poke holes in your potato and end up with a messy explosion, make sure to take the proper safety precautions for cleanup. Turn off the oven as soon as you notice the explosion and allow it to cool down completely before cleaning off the exploded potato. Use a damp rag and metal spatula to clean off the bits of potato stuck to the oven. Don’t eat the exploded potato, which may have picked up dirt and bacteria from the oven.