Cheers to the technology behind better beer
By Ed Westemeier
The Pub at Rookwood Mews taps Guinness using liquid nitrogen and carbon dioxide. The results are authentically Irish.
I'm not much of an athlete, but I do enjoy an early morning or lunchtime run. And I've noticed something about serious runners and other athletes. Many appreciate a glass of beer after a race. And most appreciate better beers, rather than mass-market products.
I mentioned this to Julie Isphording, a former Olympic marathoner who also loves an occasional glass of Guinness stout. As we discussed the unique qualities of this great beer, it became clear that she knew more than I did, so she introduced me to Charlie Wright, CEO of Wright Brothers. The company provides the gas for much of the Greater Cincinnati beverage industry.
Mr. Wright took me to the Pub at Rookwood Mews in Norwood, where he showed me a remarkably elaborate setup, carefully designed to pour the perfect pint of Guinness. A low level of carbonation; a thick, creamy head; the tiniest bubbles; the right temperature and pressure must combine for the most satisfying experience.
But these qualities of draft Guinness only have been perfected through use of a special technique. Most beer is dispensed with gas pressure from cylinders of carbon dioxide, a mixture of carbon dioxide and nitrogen, or even (shudder) compressed air. It usually works well enough, but there's a problem that customers seldom see.
By the time a keg is nearly empty, far more carbon dioxide than necessary is dissolved in a small amount of liquid. So the last pints served are likely to be foamy, which means waste for the bar, and a less-than-perfect glass of beer for us.
Guinness is very sensitive to this issue. It wants its draft beer to taste the same everywhere, which means it must be dispensed perfectly. To get the special Guinness combination of thick head and drinkability, a unique gas mixture of 25 percent carbon dioxide and 75 percent nitrogen is used. Mixing the two in exactly the right proportion, and keeping the correct pressure all the way to the bottom of every keg, present a challenge.
Guinness employs a staff of "draft technicians" who travel to pubs constantly to check on the dispensing system. They're so picky about it that Mr. Wright said the process of obtaining certification as an official Guinness gas supplier was quite involved.
The setup he showed me in Norwood is the only one in the Tristate. Instead of the standard cylinders, it has two larger, stationary tanks. One holds carbon dioxide, the other holds liquid nitrogen.
Both tanks are fixed in place, and are filled by special trucks. In fact, the small liquid nitrogen tanker used by Wright Brothers is one of the most sophisticated of its kind. Using liquid nitrogen lets the bar keep a substantial quantity on hand, without devoting much space to storage of cylinders.
Both tanks have individual regulators to feed the gas out at the right pressure, and a special mixing apparatus blends the two gases in exactly the right proportion to push the Guinness to the tap.
What happens when it gets to your glass is just as interesting. Since nitrogen is less soluble than carbon dioxide, it's released in those signature tiny bubbles. As they gradually make their way to the surface, they gather in that delightfully thick head. The remaining liquid underneath, with its low remaining carbonation, has a smoothness and drinkability found in few other beers. At the same time, it avoids the problems of flat beer which would occur if merely low pressure were used.
Next time you order one of these black beauties, give a thought to the technology that brought it to you, and join me in a toast to all the folks on the other side of the bar.