The science and spectacle of microwaving Peeps

Seventy years ago, the late Bob Born invented a candy that has found a second life as a science experiment

By Ashlie D. Stevens

Deputy Food Editor

Published February 2, 2023 4:59PM (EST)

Pink and yellow Marshmallow Peeps. (William Thomas Cain/Getty Images)
Pink and yellow Marshmallow Peeps. (William Thomas Cain/Getty Images)

By 1999, Emory University researchers Gary Falcon and James Zimring had been "studying" the solubility of Peeps for two years. During that time, they had exposed the neon sugar-coated marshmallow candies to a number of challenging conditions, initially soaking them in tap water, then moving on to increasingly intense substances like boiling water, acetone, sulfuric acid and sodium hydroxide.

Left dumbfounded by Peeps' shocking resiliency, they finally reached for Phenol, a protein-dissolving solvent that is lethal to humans in very small amounts, and soaked a single marshmallow chick in the sickeningly tarry-smelling liquid.

According to a now-archived blog post by the university, after an hour, "all that remained in the beaker was a pair of brown carnauba wax eyes floating in a purple Phenol soup."

In the corresponding interview, Falcon and Zimring apparently joked that they hoped to "[take] a cue from NASA and John Glenn" and study Peep aging and space travel. However, their academic fascination with the candy started somewhere much closer to home. In 1997, the two men and their wives had met for dinner and gorged on Peeps for dessert. That was when they hatched the experiment that started it all.

"We went straight to the microwave oven," Falcon said.

Falcon and Zimring weren't the first to microwave a Peep. And 70 years after the confection was first brought to market, they were far from the last, a fact that was seemingly embraced — or at least tolerated — by their creator, Bob "Father of Peeps" Born, who died on Tuesday at the age of 98.

Born's father, Sam, was a Russian immigrant who started Just Born, a candy company, shortly before Bob's birth. The family later moved from New York to Bethlehem, Penn., where the company is still based. After receiving a degree in engineering physics and a distinguished career in the Navy, Born returned home to Bethlehem to pursue medical school.

Falcon and Zimring weren't the first to microwave a Peep. And 70 years after the confection was first brought to market, they were far from the last, a fact that was seemingly embraced — or at least tolerated — by their creator.

While waiting for classes to begin, he went to work at Just Born and decided to stay, going on to revolutionize the candy business. As the Associated Press reported, Just Born had recently acquired Rodda Candy Co., "a jelly bean maker that had a side business producing shaped marshmallow candies by hand. At the time, it took about 27 hours to make the marshmallows."

"Bob Born saw the candies' potential, so he and an engineer at the company designed and built a machine to make them in less than six minutes," the outlet wrote. "The company's current machines, which are still based on Bob Born's design, now pump out 5.5 million Peeps per day."

Much like candy corn, Peeps are a somewhat controversial candy. According to a 2016 FinanceBuzz survey of 1,000 U.S. adults, 25% of respondents said they loved Peeps, while 16% said they hated them. The rest were noncommittal, neutral or didn't recall ever eating one.

A more interesting statistic, though, is found in one of the subsections of the survey.

"While Peeps are obviously meant for eating, their role as a festive treat is not the only reason people love them," wrote Becca Borawski Jenkins, FinanceBuzz's director of editorial strategy. "The marshmallows have carved out a niche as a source of experimentation for the young and the young at heart."

"Our survey found that nearly 1/3 of people — 32% — have microwaved a Peep to see what happens."

She continued, "One of the most popular Peeps experiments is also one of the simplest. Our survey found that nearly 1/3 of people — 32% — have microwaved a Peep to see what happens."

What, exactly, happens when a Peep is microwaved? There are approximately 379,000 YouTube videos tackling this question. Most of them are pretty similar: A Peep rotates slowly behind the microwave door, spotlighted by the orange-yellow bulb above. Within 20 seconds, it begins to expand, though not all at once. Instead, random bits of the Peep chick — its flat base, the curved neck, the tail — distend until they look like bubbles about to burst.

Some of the videos cut just as the Peeps have smoothly ballooned to about four times their original size; others allow the microwave to run just a few seconds longer, capturing the moment they burst and deflate like a supermarket marshmallow roasted over the fire. It's an inexpensive spectacle that has become part of elementary school science curricula alongside other food-based experiments like dropping Mentos in Coca-Cola or wiring up a potato battery.

In the Exploratorium's Science of Cooking section, the public learning laboratory explains the science behind the Peeps Experiment in this kid-friendly language:

When you warm air in a closed container, the gas molecules move around faster and push harder against the walls of the container. As the air in the bubbles warms up, the air molecules bounce around faster and faster and push harder against the bubble walls. Since the sugar walls are warm and soft, the bubbles expand, and the marshmallow puffs up. If it puffs up too much, some air bubbles burst, and the marshmallow deflates like a popped balloon.

When you take the marshmallow out of the microwave and it cools off, the bubbles shrink and the sugar hardens again. When the microwave marshmallow cools, it's dry and crunchy. We think that's because some of the water in the marshmallow evaporates when the marshmallow is hot.

There are a number of riffs on the original microwaved Peeps experiment, the most popular probably being "Peeps Jousting." In 2010, Smithsonian Magazine explained that the game begins with two Peeps, each of which has been speared with a toothpick "sticking out of the front of it like a lance."

"Two Peeps, so armed, are placed in a microwave facing each other," the outlet wrote. "As they are heated, they expand, until one Peep's toothpick makes contact with the other." Whichever Peep pricks its opponent first is the winner.

While "Father of Peeps" Bob Born never publicly commented on how it felt to watch people's attempts to burst the candies in the microwave, he was no stranger to the experiments.

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On Feb. 15, 2019, Bethlehem mayor Robert Donchez declared it "Bob Born Day" after a special ceremony honoring Born held at the Just Born Headquarters. There — according to The Morning Call newspaper — those gathered watched a presentation featuring archival videos about the company, which included a few taped Peeps Jousting matches.

Afterward, Matt Pye, the company's senior vice president of sales and marketing, broke into song to the tune of "Here Comes Peter Cottontail."

"He invented the chick machine," Pye sang. "Yellow, pink, blue, lavender and green, clipped the wings so the chicks won't fly away. What once took 27 hours only takes six minutes today, and the bunnies are just as popular."

He took a breath before delivering the final line: "Especially in the microwave."

By Ashlie D. Stevens

Ashlie D. Stevens is Salon's deputy food editor.

MORE FROM Ashlie D. Stevens

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Bob Born Candy Deep Dive Food Food History Just Born Marshmallows Microwave Peeps