In 1979, two University of Colorado Physics professors with a passion for hops and barley, David Hummer and Randolph “Stick” Ware — along with engineer Al Nelson — founded Boulder Beer Company. From humble beginnings in a small northeast Boulder farm shed, with roaming goats, to the spacious and bustling Wilderness Place taproom and 50-barrel brewhouse it is today, Boulder Beer Company is the little brewery that could.

And did.

Celebrating four decades of exceptional service, industry trendsetting and delicious brews, Colorado’s very first craft brewery (the 43rd brewery in the United States) will mark the monumental milestone with a free bash kicking off at noon Saturday, complete with beer tastings, live music and karaoke.

Born out of the insight of home brewers, this Boulder landmark has remained a steady constant amid the ever-changing storefronts of the city.

“The meat of the party is the specialty beers the guys have been working on,” said marketing director Tess McFadden, who has been with the company for 21 years. “It’s super small batch. We are excited to be celebrating our history of innovation.”

A Pecan Nut Brown, a Key Lime Gose and a Honey Blossom Wheat are among the new flavors that will be offered. While entry to the party comes at no cost, tasting ticket packages with a commemorative glass will be available for purchase. At 3 p.m., those who want to take their experience to the next level can buy tickets to a tasting at the brewhouse with brewmaster David Zuckerman. Attendees can enjoy 6 vintage Killer Penguin Barleywines for $20, along with the opportunity to buy bottles post-tasting.

Boulder Beer Company has also crafted a batch of “40th Anniversary Ale.” The 9 percent alcohol-by-volume oak-aged imperial golden ale with pineapple and champagne yeast, is decked out in a bottle with 1970s-inspired lettering and a sparkly green wax top. Available on draft and for purchase, the festive packaging of this brew is another detail indicative of this homegrown company’s desire to stay uniquely its own.

“It’s a big strong beer, but a light-in-color beer,” said McFadden. “Very complex.”

Providing a platform for a selection of musicians to share their artistry with beer enthusiasts, Boulder Beer Company hosts bands outside throughout the summer. The Matt Flaherty Band and bluegrass band Timber will be providing the soundtrack to Saturday’s anniversary party — an event that McFadden expects to draw up to 500 people throughout the day.

Those who want to get in on the action early can do so with a morning fun run along Boulder Creek Path, organized by Rocky Mountain Brew Runs. The run starts and ends at Boulder Beer Company, right before festivities kick off Saturday. Cost for the run, starting at 10 a.m., is $35 and includes Beer Olympics games, a Boulder Beer Co. brew, custom pint glass, coaster and sandwich from Jimmy John’s.

One of the latest refreshers, perfect for smooth summer sipping, is the rosé-colored “Perilous Prickly Pear Wheat.” The team at Boulder Beer proves inventive, steadily offering a diverse arsenal of seasonal and award-winning brews that often gain the seal of approval from committed beer enthusiasts and those just seeking an inimitable flavor.

“It’s really a group effort,” said McFadden. “Brewers always want to experiment with new ingredients, and we’re always looking to see what the market wants.”

At Saturday’s event, comment cards will be distributed to tasters so they can weigh in on which brews they would like to see brought into permanent rotation. This feedback process has allowed Boulder Beer Company to produce larger batches of sought-after items to the consumer. “Hazed & Infused,” once only brewed for a limited time, was brought on board permanently after drinkers expressed their adoration for the now bestseller.

“It’s interesting to see where the industry goes,” said president Gina Day, an original owner of Walnut Brewing Company who purchased Boulder Beer Company with her husband Frank in 1990. “Now there are small breweries on every corner.”

Markings of the brewery’s initial efforts can be found in the framed original faded labels of “Bitter” “Porter” and “Stout” and the 1979 brewer’s license that graces the often-packed taproom. Today, current cans bare colorful and eye-catching designs by Boulder-based international design firm Moxie Sozo.

The recently upgraded outdoor vine-draped patio, dotted with flowers planted by McFadden herself, is the ideal place to enjoy one of the latest offerings crafted by the brewmasters at Boulder Beer Company. A smoke shack serves up tender barbecue items to patrons, cornhole boards offer a mid-day game break and sun shade sail canopies keep the rays at bay.

“I’m proud of the really different and enjoyable culture that we’ve developed through the years,” said Day. “In general, smaller microbreweries that aren’t bought by larger companies still have that culture.”

A vibrant outdoor mural, designed by Boulder’s Husky Creative for the brewery’s anniversary last year, pays artful homage to some of Boulder Beer Company’s most noteworthy beers. A mushroom representing “Hazed & Infused,” a lighthouse for “ Due East New England Style IPA, a buffalo for the mildly malty “Buffalo Gold Golden Ale” and an orange slice for “Pulp Fusion Blood Orange IPA” all center around a psychedelic astronaut.

In addition to offering unique flavors throughout the years and an environment that lends itself to leisurely afternoons and laid-back evenings, Boulder Beer Company has made donations to multiple Colorado-based charities. Certain proceeds from a Saint Patrick’s Day puppy parade, that brought around 200 costumed dogs into the taproom, were donated to the The Humane Society of Boulder Valley. For Pride month, the crew created “Gender Fluid” and donated 10% of the German-style pilsner’s sales to The Human Rights Campaign. In 2008, Boulder Beer Company became a sponsoring partner in Boulder’s “10 for a Change Challenge,” an initiative designed to reduce energy consumption by 10 percent via eco-friendly improvements for increased energy efficiency.

With full-strength beer now on the shelves of supermarkets and convenience stores throughout Colorado, Boulder Beer Company’s product has reached an even bigger market.

“For consumers, it’s an awareness window to us,” said Day. “Walking down the grocery aisle they can find us. It gives us more exposure. It’s all about keeping a pulse on the consumer — on what their needs and wants are. I credit our staying power to the team here continuing to recreate, reinvent and stay current with the times.”

From being super dog-friendly, even offering a burger pet-owners can purchase for their canines, to having a full bar providing an array of spirits for those who prefer wine or bourbon, Boulder Beer Company continues to be a hub for the community to gather and graze.

“Over 40 years, so many breweries have come and gone,” said McFadden, who had her wedding reception on site in 2005. “I’m really proud that we have been able to stand the test of time.”

If you go

What: First to Forty: Boulder Beer Company’s 40th Anniversary Celebration

When: noon- 10 p.m. Saturday, Timber plays at noon and Matt Flaherty Band plays at 3 p.m., free brewery tours at 2 p.m. and 4 p.m., karaoke at 6 p.m.

Where: Boulder Beer Company, 2880 Wilderness Pl., Boulder

Cost: free, with select tasting packages available for purchase $10-$20

More info: boulderbeer.com/pub-events/40th-anniversary-celebration