Visiting the factory where Peeps are made, in Bethlehem, Pa., is a true Willy Wonka experience. The building is crammed with pipes full of marshmallow and hoses full of sugar. Spray guns spray food coloring and flavors. Even the “whoops” moments that occasionally happen when the candymakers are testing new products seem like fun: “We have an engineer who is known for pushing buttons he’s not supposed to,” says Daniel Moyer, a food scientist at Just Born Quality Confections, the company that makes Peeps. “Sometimes he ends up completely covered in marshmallow.”

It wasn’t always so fun. Back in the early 1950s, some employees at the Peeps factory were ending every shift with limp, sore arms. They had spent hours hand-squeezing marshmallow into the shape of tiny chicks. Back then, each individual Peep took 27 hours to make from start to finish.

That all changed in 1954. That’s when Bob Born, who was a member of the family that founded the company, and a colleague invented a machine that could make Peeps automatically. Now it takes only six minutes from the moment marshmallow meets the conveyor belt to the final boxing.

Bob Born died in January at age 98. But his legacy lives on at that same factory, which now houses four production belts. They pump out 5.5 million Peeps on an average day, in all kinds of shapes (like bunnies, or skulls in the fall), flavors (sour watermelon, anyone?) and colors.

Of course, the classic Peep, especially during the busy Easter season, is still that fluffy little yellow chick. Here’s how they’re made.

STEP 1

Preparing the Sugar

The bright yellow (or pink, or blue) sugar that coats Peeps chicks starts as the same white stuff you have at home — except the Peeps factory pours it out of 100-pound bags. Four bags at a time go into giant rotating drums that tumble the sugar the way a dryer tumbles clothes. Then a worker pours food coloring into a funnel that feeds a spray gun, which shoots it into the drum, where the tumbling mixes and dries it.

The sugar-dyeing process takes about 18 minutes. Then the sugar is emptied into giant bins and brought over to the beginning of a long conveyor belt, where a vacuum sucks up the sugar and spreads it out on the belt.

STEP 2

Cooking the Marshmallow

If you’ve ever bitten into a Peep, you know that underneath its brightly colored sugar skin are insides made of marshmallow. To create all that fluff, 1,400 pounds of water, sugar and corn syrup are first heated into a hot, sticky syrup that candymakers call a bob. Gelatin is added to help the bob stiffen up so that it can eventually hold its shape, along with vanilla and other flavors. The process is overseen by marshmallow cooks, who hold one of the most specialized jobs at the factory. It’s their responsibility to make sure the marshmallow is perfectly fluffy — if it isn’t the right density, it could throw everything off.

STEP 3

Shaping the Chicks

How exactly does the marshmallow mixture transform from a blob of goo to a brood of beaky little chicks? Well, that’s a secret that Just Born keeps under wraps. But here’s the basic idea: The liquid marshmallow is pumped through an aerator — a wide tube full of spinning wires that whip air into it, making it fluffy — and into a machine called a depositor. Then the depositor squeezes the marshmallow onto the sugarcoated conveyor belt.