New Beer Tap Turns Barrel-Aged Brews into Nitro Pours
By Matt Allyn
Barrel-aged beer meets nitro carbonation in the latest brewing innovation from the Dogfish Head Brewery.
This is the Rack AeriAle system, a new beer-serving technology that can pull a pint from a wooden barrel, chill it, inject nitrogen, and fill your glass within seconds. Yes, we're talking about the same bubbles that give Guinness its thick head and creamy feel, which was invented by the iconic Irish brewery. But Dogfish Head's Rack AeriAle brings nitrogenation to brews aged in wine and spirits barrels.
Dogfish Head designed the Rack AeriAle in partnership with draft beer specialists AC Beverage, the company that built Dogfish Head's first tap system in 1995 in Rehoboth Beach, Delaware. But for this new beer-spewing contraption, the biggest hurdle they faced was creating a way to pull beer directly from a wooden barrel and into a tap line. Normally, when a brewer decides a batch of barrel-aged beer is ready, it's transferred to a stainless steel keg which is pressurized and carbonated with CO2. No existing tap system could serve beer directly from a barrel, much less cool and carbonate it in the tap line.
The most exciting aspect of the Rack AeriAle is that the balance of nitrogen and CO2 can now be customized for each beer.
So the duo began outfitting a stainless steel swan neck hose with a gasket around the top. The swan neck, regularly used by brewers and winemakers to move liquid from a barrel, reaches the bottom of the barrel and draws beer out. Meanwhile, the gasket attached around the bunghole to create a seal that keeps out oxygen (an enemy of fresh beer) also creates the pressure to push beer out of the barrel and into the tap line.
Out of the barrel, the beer runs through a heat exchange, which drops the beer down to a pleasant serving temperature. Next, it hits an in-line nitrogenator which injects a mixture of nitrogen and CO2. (That same nitrogenator also keep the barrel's empty space filled with gas to prevent oxidation.) Finally, the beer hits a standard nitro tap where it runs through a restrictor plate at the end of the line, where the beer's essential shoved through six tiny holes. This pulls the gas out of the solution, creating that mesmerizing cascading bubbles effect nitro beers are known for.
The most exciting aspect of the Rack AeriAle, says Dogfish Head founder Sam Calagione, is that the balance of nitrogen and CO2 (normally a 3-to-1 ratio) can now be customized for each beer.
"If we're serving a beautiful imperial stout...and want to emphasize the soft, creamy notes, we'd bump up the nitrogen," he explains. "But if you're serving a lambic style sour and want that bite of carbonation to interweave with acidic notes, you'd bump up the CO2."
Calagione is unveiling the Rack AeriAle in conjunction with Boston's Extreme Beer Festival this weekend. And the first system will be installed in Eataly Boston's Terra Restaurant, with a barrel rack sculpture holding 15 barrels with three goosenecks. The design is meant to hold five wood barrels each of three different beers, with one barrel of each beer tapped while four of its siblings wait and age.
Dogfish Head plans to install a smaller Rack AeriAle this spring at its Milton, Delaware tasting room. Calagione says it'll hold six barrels with two goosenecks and feature beers like the 12-percent ABV Palo Santo its 18 percent World Wide Stout. "You need beefy, flavorful beers that can hold up with the complex aromas and flavors of wood."
Coincidentally, Guinness announced plans earlier this week to open an experimental brewery and tasting room in Baltimore. Maybe someday we can taste the world's first nitro beer served through the latest nitro technology.