But a decade later, the solution had become a problem, and the search for a better can closure began. In the early 1970s, Coors came up with its “environmental package,” a curious two-opening top—the first was a small pressure-release valve, the second was a larger aperture for drinking—that some readers may recall. Like Coors itself, which for a Midwesterner had a certain exotic appeal, there was an intriguing novelty to the design of the “press tab,” as the company called it; one that quickly lost appeal for drinkers (particularly those on the downward slope of a six-pack) trying to puncture through, and then retract their fingers from, the smaller, sharp-edged opening.
But Coors wasn’t the only experimenter; as the website Rustycans.com notes: “Crown, Cork, and Seal tried a top that you pressed down then slid a tab to one side, pushing a hole into the can top. Continental’s Envir-o-can required the consumer to pull a metal strip from the top of the can, revealing several small holes in the top from which to pour the beer.”
The solution came from Daniel F. Cudzik, an engineer with Reynolds Metals, who for years had been toiling away on what would what become known as the “Sta-Tab.” As Cudzik told Studio 360, his search for a “convenience top” that was “more practical and less prone to litter” came to fruition one night when he was in living room, “half watching a movie.” While the idea might seem simple to a consumer raised on nothing but stay-on tabs, the design required some elegant engineering (and some subsequent legal battles over alleged patent infringements).
As Cudzik described the problem in his 1975 patent application: “The opening construction of the invention requires a tab which must be stiff against transverse bending and yet flexible enough and tough enough at the connection between the tab end wall to permit lifting and retracting the tab without causing a fatigue crack at the connection.” As elegantly explained in this video, the design operates both as a “second class” and as a “first class lever” at different points in the can-opening process—redirecting loads and shifting the fulcrum—using the inherent pressure from the carbonated beverage in its favor.
When the Sta-Tab launched in 1975, on Falls City beer and, quickly, other beverages, there was initial period of consumer testing and education (as soberly described by the New York Times in 1976: “New Yorkers are now faced with a new problem: how to open the new Stay-On-Tabs on Coca-Cola cans currently being sold in New York”). But the Sta-Tab was here to stay.
From a waste point of view, the consequences were clear: Notes Petroski, this time in Invention by Design: In the 16 years after Cudzik’s patent, “the stay-on-tabs alone amounted to over 4 million tons of aluminum that was recovered and recycled rather than discarded.” Curiously, the problem of ingested tabs has not gone away: In 2010, an article in Pediatric Radiology identified 19 cases of accidental ingestion at a single children’s hospital (with the majority radiographically invisible). Also still with us: can tab arts and crafts.
Cudzik said on Studio 360 that he thought can tab design had reached a point “where I don’t believe there’ll be too many changes anymore.” But is design ever done? A 2007 study that looked at the ergonomics of can-tab pulling (using finite-element analysis to analyze the “deformation of the fingertip pulp”), for example, suggested that a larger tab would reduce discomfort. And there’s always another basement tinkerer on the horizon. A Canadian golf course groundskeeper, for instance, is making the rounds with a new “smart tab,” which tackles the ergonomics problem with a tab that curves slightly upwards. The tab also spins around to act as a kind of cover for the opening (to keep out debris and bees). Will it catch on? Who knows—but the work of design , as much as it is about eliminating obvious flaws, is also about bringing to light the things we only realize are problems the very moment we no longer have to live with them.