SAN FRANCISCO – A small annoyance in American’s beverage interactions may be getting a little less exasperating.

Shorter, thinner plastic caps that proliferated on milk, juice and other liquid cartons over the past few years were better for the environment but they could also be frustratingly difficult to open. Who wants to struggle with a cap first thing in the morning?

A new version of those caps, from an Illinois company, is hitting store shelves. Its design renders the tormenting tops a little less vexing by making them taller and spacing out the ribbing.

“It’s the knurling,” said New Berlin, Wisconsin, resident Fred Wolden, who recently noticed the difference. “They’re just easier to open.”

“Knurling?” you ask. Yes. That’s the textured pattern of lines along the carton’s plastic cap. That, plus being a little taller than their more frustrating-to-open counterparts, makes them easier to twist.

“You can get a good grip,” said Wolden. “It’s being able to put your thumb and finger on the cap. And then when you turn it, the knurls help with the turn.”

Americans consume about five million gallons of milk each year, about 17% of which is sold in traditional paper cartons. That’s in addition to juice, non-dairy milks, broths and other liquids that come in what the beverage industry calls “gable top” packages.

Almost all of them now come with nifty twist-off plastic caps, a miracle of modern packaging except as the closures grew shorter and thinner, they became harder to open.

Why did milk cartons get harder to open?

Manufacturers and food distributors in the multi-billion-dollar plastic food packaging industry have faced increasing pressure from consumers and environmental health advocates to design more environmentally sustainable and healthier containers.

Over the past decade and more, American food and beverage companies have made great strides in reducing the amount of plastic used to contain their products. This did several good things for the industry: reduced the amount of plastic needed**,** making items lighter which saved money on transportation costs which also reduced carbon emissions.


Companies “want to make things, safe, sealable, transportable and affordable,” said Andrew Dillon, a professor at the University of Texas. “But the tradeoffs can be hard, Dillon said. “The tradeoffs can be hard.”

Unfortunately, many of the first versions of the shorter, lighter “fitments” (as the whole plastic spout is called) for milk bottles and other packages are harder to open, something USA TODAY reported on in December – a story that seemed to have touched a nerve with readers.

Caps on the “greener” light-weight fitments required less plastic. But they were about a third of an inch, while the older, heavier versions were almost a half-inch. That**’s** enough to make them harder to unscrew.

“We’ve had to resort to using a pipe wrench to open them,” said Wolden, a retired contracting officer with the U.S. Coast Guard. He and his wife keep a pair of pliers in their kitchen drawer to wrestle with contrary caps.

But there’s hope for those struggling with those early morning “I just want to open the milk carton and have some cereal” blues.

Silgan Closures of Downers Grove, Illinois recently developed a newer spout and cap combination that uses less plastic but is as tall as the old ones.


A lighter cap that’s still easy to open

It might not seem that a simple milk-pouring spout would require years of testing and design, but it did.

Silgan started looking at its designs several years ago. First the engineers tried designing a closure half as tall as their previous versions. They weren’t happy with the initial results.

After multiple iterations over several years, Silgan engineers hit upon something they were pleased with: A normal-height cap that was lighter in weight due to thinner walls. Their design, with spaced-out ridges – the knurls – on the cap, also had the happy side effect of making them more prominent. And that made it easier to get a grip on.

“We put them in consumers’ hands, had them open them, and tell us what they thought, and that helped us narrow down the designs that were good,” marketing director AJ Miller said of the design team. “Then we had people use them at home and give feedback. All this took place over three years.”

The result was the Silgan F15 cap.


Good design wins out

“It looks good,” said Alaster Yoxall, a professor of packaging ergonomics at Sheffield Hallam University in the United Kingdom. “If it’s a lot easier and uses less plastic then it’s a win-win.”

The new caps are beginning to appear across the country but haphazardly. It’s very possible to reach into the milk and beverage case at a supermarket and find several different types of caps, sometimes even on the same brand of milk or other drinks.

“We are excited about the positive customer and consumer response to the F15 Fitment,“ said Elizabeth Wiese, president of Silgan Closures.

In Wisconsin, Fred Wolden is just happy he doesn’t need to get pliers out of the kitchen drawer quite as often.

“I know that sounds crazy, and I’m not a weak person,” he said. “But when you grab [the new cap], you can grip it a little better. And when you turn it, the knurls help with the turn.”