This past weekend, friends and I made a pilgrimmage to Founders Brewery in Grand Rapids, Michigan. What happened between myself and a certain beer in the pub is probably best described as a tragic love affair. With Valentine's Day approaching, consider the rest of this post something of an open love letter to Founder's Frangelic Porter. It first caught my eye with its deep color, and then stole my heart with flavors of hazelnut, chocolate, and coffee, not to mention an exquisite creaminess.

Naturally, after my first glass of this unfamiliar and exotic delicacy, I wanted to take a growler with me. I sauntered up to the bar, looking forward to taking my new love back home to Chicago to meet my friends, and maybe even watch the Super Bowl with me. "Sorry, no growlers of the Frangelic," the bartender replied. "It's on nitro." My heart sinks. The same technology that creates the beautiful head and fantastic creaminess of the porter is the very reason I can't take it home in a growler. This started me thinking: What exactly is nitro pour, and why does it stand between me and 64 ounces of malty bliss?

Beers on nitrogen pour aren't all that common. Most beers on tap are pressurized by carbon dioxide, which forces the beer out of the keg and through a draft line. With nitrogen systems, a ratio of nitrogen and carbon dioxide around 75/25 is used to pressurize the beer. This requires special equipment that can withstand higher pressure (or just a bit of creative engineering with existing tap systems). When stouts were introduced in Britain, the only way to serve them was by pouring or pumping directly from a cask. Nitrogen pours recreate something of that original experience.

The nitrogen pour does this in a few ways. Most notably, it creates a creamier mouthfeel to stouts and porters. Nitrogen bubbles are smaller than carbon dioxide bubbles, meaning beers don't feel as carbonated when served on nitro. Nitrogen is also a large component in the air we breath, so the bubbles in the head don't feel the need to escape into the air as quickly, producing a thicker head. It's no surprise that the most common beer experienced on nitro pour is a Guinness.

Because of this special method of dispensing the beer, nitro beers don't travel so well. In growlers and even pitchers, it's hard to pour them properly, and they lose a lot of the magical texture that the nitrogen imparts. You likely won't see the cascading bubbles that ideally run from the head into the glass, and the silky feeling won't be the same on your palate. After researching the technology of nitro pour, I've come to grips with the fact that my relationship with Frangelic Porter was a fleeting one. While I'd love to see a bar in Chicago feature the beer, it might not be in the cards. Ultimately, 'tis better to have loved and lost.

–Kate Bernot