Perfect popcorn, the physicist’s way

3 minute read

Tired of unpopped kernels and burnt popcorn? Sick of that yellow salty/greasy artificial “butter”? Upgrade your popcorn experience with these simple tricks and make perfect popcorn by understanding the basic physics behind it. You’ll be rewarded by a healthy, whole grain and low calories delicious snack.

First, let’s look at how a corn kernel pops:

Heat transforms the water content of the kernel into water vapor, and when the pressure is high enough, the kernel pops. That brings our attention on the two main parameters of our experience : water content of the kernels and heat transfer from the pan to the kernels.

Water content : soak it

If your corn kernels are a little old, chances are they do not pop properly. Soak them in water for 15 minutes, pat them really dry and pop them.

I tried this simple experiment : I popped 1/4 cup of kernels, then I popped 1/4 cup of soaked and pat-dried kernels. I ate the two popcorn bowls (joking – I saved most of it for later) and counted the unpopped or half-popped kernels. The result? It’s a tie : 10 for the dry kernels and 13 for the soaked kernels (the difference is not significant enough to draw a conclusion). My kernels are still really fresh, so I will have to retry this experiments with older and drier kernels to see if it really makes a difference (but according to Bill Nye the science guy, it does). So, if your kernels are still fresh skip the soaking step.

Heat transfer : a little oil goes a long way

I learned this the hard way. I was tried to make a no-fat popcorn but it was a disaster. The kernels popped very unevenly, so by the time the last ones popped, the first ones were burnt. Also, they were smaller than usual, and often hard and half-popped. Disaster, I say.

Oil is essential to pop corn kernels on the stove top. Oil promotes an even heat transfer from the pan to the kernels. A heavy bottomed pan also helps for the same reason. I usually use 0.5 to 1 tablespoon of olive oil per 1/4 cup of kernels.

To successfully pop kernels on the stove top, heat the oil and the corn kernels on hi in a heavy bottomed pan with a lid on. Lift the pan, shake it and put it back on the stove top from time to time so that the kernels are heated evenly. Do that lift-and-shake maneuver more often when the kernels start to pop. When the pops are 2 seconds apart, remove the pan from heat and let it cool for a minute with the lid on. Transfer to a serving bowl and salt to your taste. Mmm…

Other tips

  • Use very fine salt, such as the one you get from a salt mill. It sticks to the popcorn, as opposed to table salt which ends up at the bottom of the bowl.
  • Olive oil is healthier than many other oils, but it doesn’t withstand heat very well. Grape seed oil would do a better job here.
  • Plain corn kernels are way cheaper than buying bags of microwavable popcorn. Buy organic ones if you can find them. They are 4$/kg at my local grocery store. Beat that, Orville Redenbacher!
  • 1/4 cup of kernels yield about 5-6 cups of popcorn.
  • There are about 35 Cal per cup of popcorn, plus the calories from the oil (about 15 Cal per cup if you used 1 tbs of oil for popping), so it’s about 50 Cal per cup of oil-popped popcorn.
  • Pimp your popcorn with spices and herbs. I like mixes such as cumin-cayenne-allspice-cinnamon, or Italian herbs and grated Parmesan cheese. Be creative and share your favorite popcorn flavor in the comments below!