Beer has a new pilgrimage within its Irish territory—Open Gate Brewery, the experimental brew house of Guinness, which quietly just began welcoming visitors into their century-old idea lab for the first time. Ever.

The two-story factory warehouse where Guinness brews its newest recipes has been hidden in plain sight behind a common black lacquered door among the cobblestone streets of St. James’ Gate, the Guinness Dublin campus. Right around the corner is the Guinness Storehouse, one of Ireland’s most iconic tourist landmarks—a seven-story, interactive museum dedicated to the heritage beer, replete with panoramic top-floor bar.

Open Gate is much more intimate. Inside is a small warehouse taproom with some chalkboard menus, a purple up-lit brewery in the background, and a few tables made of reclaimed wood where you sit and try a mix of unreleased, small-batch Guinness and the largest selection of international Guinness varieties in the world. Some, like Guinness Foreign Extra Stout, are only widely available in the Caribbean and Africa, and they have the only tap in Ireland that pours Nitro IPA, a variety only found in the U.S.

The brew house is open on Thursday and Friday nights, reservations are required, and space is limited. For the six-Euro price of admission, you get a flight of four 1/3-pint beers of your choice. Find one you like and it’s only five or six Euro more for a pint.

Each brew on offer has the telltale smoothness of a nitro beer (a creamy beer with smaller bubbles that’s been tapped with nitrogen rather than carbon) that Guinness helped to pioneer, and that’s having a big moment in the American beer scene—and not just with stouts. Sam Adams is releasing a new line of nitro beer sometime this year and in November, Left Hand Brewing, a small craft brewery in in Longmont, Colorado hosted the second-ever, nitro-exclusive beer festival, “Nitro Fest.” (Don’t let the chemical names scare you, think of nitro as beer's version of molecular gastronomy).

“We wanted to have conversations about our developmental beers with people at an earlier stage,” Padraig Fox, Manager of Open Gate Brewery, says from behind the bar as he hands me a Hop House 13, a light and fruity Guinness that’s just been released in Ireland. The concept of Open Gate Brewery, he explains, mixes the amusement of sampling unreleased, small batch, and market-specific Guinness (aka “drinking”) with knowing your feedback could, potentially, weigh in on the brand’s next release. Once you’ve had some time with your pours, Guinness encourages you to give your opinion to your bartender or server. “The feedback you give will definitely factor in to how we develop our recipes and if a product is ready to get produced,” he says.

Fox walks us over to a scotch whiskey barrel set off to the side. “This beer can’t legally be sold, but we can let you have a taste,” he says as a milky, obsidian-colored brew pours out of the tap. “This is a personal experiment of our brewers. This is where our ideas begin. What do you think?” 

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