The Cloudy Reason Reese's Peanut Butter Cups Have Ridges

Reese's Peanut Butter Cups are continually ranked as one of America's favorite candies. With their combination of smooth, sweet milk chocolate and salty, slightly crumbly peanut butter, these disc-like treats have been considered iconic for nearly a century. Reese's Cups fall somewhere between a classic candy bar and a truffle, but that's not the only feature that makes them unique. For decades, one question has puzzled numerous loyal snackers: Why, exactly, do Reese's Peanut Butter Cups sport those zigzagged ridges around the perimeter? 

Spoiler alert: there's no clear-cut answer, but there are several tasty contentions to support the confection's crimped design. For example, one theory states that the ridges are a purely aesthetic way to differentiate Reese's from other indulgences on store shelves. As one Redditor wrote, "The design is very iconic and about as recognizable as the logo itself."

By incorporating an accordion-esque edge, Hershey's has created a visual element that makes its product instantly recognizable. This strategy is important in the crowded candy market, where brand recall is often a key to success.

It's also believed that the ridges on Reese's Cups serve a truly functional purpose. In other words, the ridges create a thick boundary between the chocolate exterior and the peanut butter filling, allowing a solid amount of chocolate in each bite. This promotes a more satisfying eating experience, as the contrast between the two textures and flavors is noticeable. Hershey's Chocolate World shares that a Reese's Peanut Butter Cup's illustrious "gear wheel" shape — with the ridges representing a gear's teeth — does indeed offer a high peanut butter-to-chocolate ratio.

An insightful member of the Showerthoughts subreddit even suggests a hypothesis that the ridges make it easy to remove the dark brown paper wrapper without getting chocolate on your fingers. Yet another theory states that this prominent attribute was designed to resemble the slight indents in cupcakes, which are formed by the liners as the batter bakes.

Regardless of the reason behind their grooves, Reese's Peanut Butter Cups are among the best-selling candies on the planet. The brand also releases a few holiday-themed, seasonal, ridgeless shapes throughout the year, including hearts for Valentine's Day, eggs for Easter, pumpkins for Halloween, and trees for Christmas. This limited edition Reese's offer a higher volume of peanut butter per serving, much to fans' delight. Oh, and in case you were wondering, there are 66 ridges on a standard Reese's Cup.