“I was ready to give up,” Koch said. “It was disappointing.”

The Bunker Hill crew retreated for several months and examined whether canneries could implement the eight test designs. It would likely cost millions of dollars to make changes to the manufacturing process, which has been refined over decades to produce roughly 2,000 cans per minute for pennies each.

In June 2012, the researchers traveled to Colorado to share the prototypes with Ball, which makes cans for Boston Beer’s Twisted Tea line. Ball showed them cans with rough edges — thought to help stimulate the lips and taste buds. The manufacturer also revealed several of its own innovations, including cans with different shapes and containers with extra holes on the lid. The Bunker Hill team decided to test all the ideas.

“We knew the odds were against us to get a can that would meet Jim’s expectations and make it to drinkers,” Gladstone said.

By the next month, it was clear Boston Beer’s research focus was off the mark. People thought the rough edges were a manufacturing flaw. The additional holes on top had little effect on flavor. But a blind taste test showed 10 out of 10 participants preferred a design featuring an hourglass curve below a wider lid.

On July 18 at 1 p.m., the Bunker Hill battalion invited Koch into the South Boston conference area known as the Tap Room. Gladstone was nervous. He figured the project was about to get killed. Researchers placed the eight designs in front of Koch and filled them with beer from a pitcher. Koch started sipping and silently began rearranging the containers in order of preference. After a few minutes, the hourglass can was number one.

Victory finally seemed possible. Over several months, Boston Beer tweaked the design six times, altering the slope of the curves, the size of the lid, the shape of the lip, and the placement of the opening. The aim was to make the experience as close to drinking from a glass as possible.

Bunker Hill also hired Desrochers, the beer specialist, to conduct professional tasting panels made up of beer aficionados who go through a year of training in the art of rating brews.

On Thursday, Desrochers gave his final evaluation to Koch. The new can, he said, had strong benefits both in ergonomics and flavor. The hourglass curve and wider lid deposits the beer further in the mouth so a drinker doesn’t have to tilt his head back.

“With a traditional can, you feel like you’re sucking liquid out,” Desrochers said. “With the new design, the beer flows in nicely . . . and you don’t get the sensation that it might spill out the side of your mouth.”

The bigger lid forces people to open their mouths wider, allowing more air to pass through and go up into the nasal passages. This increased exposure to the smells brings out the flavors of the beer — the hops, the grains, the fruitiness — earlier in the drinking experience, which is what consumers associate with a fresher beverage, according to Desrochers. And the outward-turned lip pours the beer directly on the palate, maximizing the sweetness from the malt.

“I was very skeptical at first. I’ve seen lots of can changes over the past 30 years and not a lot has had a true effect on the drinking experience,” Desrochers said. “But there is a meaningful difference here.”

And with that definitive stamp of approval, Bunker Hill is headed to market. New canning equipment has been ordered, and the plans are to roll out cans of Sam’s Boston lager and Summer Ale in time for beach-cooler weather.