As a sixth-generation brewmaster, Jim Koch, founder and owner of Sam Adams beer-maker Boston Beer Company, knew right away he was looking at a piece of brewing history.

He spotted an old wooden keg while on a visit to an Augusta beverage store.

Koch had seen similar kegs before, including in family photos of his great-grandfather, a brewer who was missing one of his fingers. Koch believes the finger was lost while his great-grandfather was stacking similar kegs which, when full, can weigh more than 200 pounds.

“He was missing a finger and I’m pretty sure that’s how it happened, stacking up one of these heavy kegs like this one,” Koch said while standing in front of the approximately 75-year-old wooden-staved keg bound together with sharp-edged metal hoops. “You get your finger caught between two of them and it’ll cut like a knife.”

The keg, with “Boston Beer Co., Boston Mass.,” burned into each end, was presented to Koch recently at Pine State Trading’s beverage distribution center in Gardiner, a gift from the Damon family. The Damons own six stores in central Maine, including Damon’s Beverage Mart in Augusta — the former Lou’s Beverage Barn — where, a couple of years ago, Koch had spotted the keg while making the rounds of the store.

The Damons found the keg, which they said had apparently been purchased by the store’s previous owners, Elsie and Lewis “Lou” Boucher, while they were going through the store after they purchased it from the Bouchers in 2009.

Koch, according to James Damon, one of the owners of the group of local stores, visits Damon’s Beverage Mart about once a year.

Koch said he visits stores that sell Sam Adams to make sure stores only sell his beer fresh.

Shortly after the Damons had taken over the store, Koch spotted the keg on one of those visits, and inquired about purchasing it. The Damons were initially hesitant, but ultimately agreed Koch could have the keg — which one estimate projects could be worth about $1,500 — for free.

“It’s important to him,” James Damon said of why they gave the keg to Koch. “To us, it was just a barrel sitting there. It had sentimental value to him. We didn’t need to make a profit on that.”

Jeff Damon, another co-owner of the Damon’s stores, said he felt like the keg was going home, to its rightful place.

Koch said the keg will be put on display in the museum at his Boston Beer Company’s brewery in Boston, where it will join the only other such keg he’s ever seen.

“This is the only one I’ve ever seen, outside of the one we have at the brewery,” Koch said. “It’s like finding a unicorn.”

Koch started his version of Boston Beer Company in 1984, and has built the company into the country’s largest craft brewer. He said his family has been brewing beer since 1840.

However they didn’t do so in Boston. Koch is from Ohio.

But his is not the first Boston Beer Company. The first, and the source of the old keg, Boston Beer Company started in 1828 and, until it closed in the early 1970s, was the country’s oldest brewery, according to Koch.

Nick Alberding, managing partner at Pine State Beverage, a division of Pine State Trading, praised the Damons for parting with the old keg.

Pine State’s Al McPherson, vice president of sales and marketing, was with Koch when they came across the keg. He said the way Koch reacted to it, he could immediately tell it was important to him.

Koch said the keg, which he said likely dates to “post-prohibition, but not by much,” was probably delivered to a bar and emptied, but never found its way back to the brewery.

“It’s an empty that never got returned,” Koch said.

Keith Edwards — 621-5647

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