The project’s code name — Bunker Hill — hinted at the formidable challenge Boston Beer Co. faced: could the craft brewery that revolutionized American beer put its Sam Adams lager in a can without sacrificing the taste millions of consumers expect with every sip?

For decades, company founder Jim Koch snubbed aluminum containers because of the metallic flavor they impart to liquid. His resolve cost the Boston-based brewer millions of dollars in potential revenue from airlines and sports arenas, a price Koch said he paid to preserve the quality of a brew whose tagline until recently was: “Take pride in your beer.’’


Koch refused to budge when manufacturers created a can lining that kept the beverage from touching aluminum, or as other craft brewers, such as Oskar Blues, Sierra Nevada, and Fat Tire began embracing the metal containers over the last 10 years. But two springs ago, Koch decided to take another look at the market, and ultimately, create his own can.

“We thought Jim would eventually change his mind and he’d just come around,’’ said Jay Billings, director of innovation and marketing for Ball, a Colorado canning company that packages Oskar Blues and 150 other craft brewers’ products. “It took us a long time to understand that Sam Adams was not going to go in a standard 12-ounce beverage can.’’

The quest for a better can took the Bunker Hill team to a plastic coffee lid collector in New York, a museum of beer cans in a Taunton basement, and tailgating parties at Gillette Stadium. The two-year effort cost more than $1 million, including the hiring of a renowned design firm and professional beer consultants, as well as the purchase of expensive canning equipment. Now, Koch is finally ready to release his precious Boston lager in a patent-pending can he claims is superior to the regular metal vessel most people drink from.


“I’ve been the holdout,’’ acknowledged Koch, who founded the company 29 years ago. “I’ve been the purist.’’

To launch the initiative, Koch contracted with IDEO, the high-profile designers of the original Apple mouse, and assembled the Bunker Hill team in Boston, led by commander (a.ka. project manager) Peter Gladstone.

In summer 2011, they traveled to Ball’s factory near Denver to study the canning process — the thickness of aluminum, molecular properties, how beer pours from a can, and what impacts the flow. They hung out with well-lubricated football fans in Foxborough to understand why drinkers prefer beer in cans — they account for roughly 57 percent of the US retail market, according to SymphonyIRI Group, a Chicago market research firm. The Bunker Hill team interviewed taste experts around the world and examined thousands of plastic coffee cup lids to understand the range of drink delivery options (the peel, the pucker, the pinch, and the puncture).

The big discovery: Conventional cans don’t allow enough air into people’s mouths as they drink. Turns out, much of what consumers believe they taste is actually smell — that’s why food tastes so bland when people are congested. Increasing exposure to the beer’s aromas of hops and fruit can make a big difference in taste, said Roy Desrochers, a professional beer taster at GEI Consultants in Woburn.

So the team began looking for ways to improve air flow. Over several months, IDEO proposed dozens of designs and created eight prototypes that expanded the size and shape of the can’s opening. Larger apertures — one shaped like a bell, another like a peanut — were supposed to enhance the air flow and access to aromas. The most promising idea, according to Koch, was a design that allowed drinkers to tear off the entire top.


In winter 2011, Gladstone passed around the prototypes to workers at Boston Beer’s office in South Boston and at the brewery in Jamaica Plain. They noted modest improvements in taste. But there were problems: the tear-off top violated litter laws in most states. And the gaping opening made people nervous. They were worried about cutting their nose or lip on the edge, afraid of bugs flying inside, or the drink spilling.

“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.

As the beer experts popped open the cans for one last tasting on Thursday, Koch scrunched up his nose. “I’m still getting used to that sound,’’ he said.