We here at Beer Cache have just returned from a three-week brewery tour of the great craft brew state of Alaska.
We were lucky enough to stroll around bright tanks, peak into mash tuns, hang out in chilled serving fridges and pull nails from barrels to sample back-room casked ales with the generous owners and brewers of some truly amazing micros.
One of the most interesting things we discovered during our dutiful bout of tasting was the use of nitrogen in lighter beers, primarily IPAs.
Traditionally, beer gas is used to serve beers that are creamier in mouthfeel (stouts, porters, milds and bitters) as the smaller bubbles and the lighter carbonation are fantastic complements to these styles.
These ales are commonly served a little warmer, which also adds to the fuller, smoother taste.
As you can imagine, a warmer, less carbonated beer has to hold its own, so a delicious hop aroma/flavor and a hearty grain bill are key features for a nitro beer.
However, an IPA was certainly not an ale that we were expecting to see served smooth and creamy.
If you have ever left your home on St. Patrick's Day, then you have tasted a beer carbonated and pushed with nitrogen: Guinness.
The use of nitrogen as a carbonation and serving gas is really very clever. It is an artificial carbonation method that mimics the texture of that lovely casked-ale style: lighter in carbonation with smaller, silkier little bubbles.
(Refresher: cask conditioning is priming your beer with sugar, therefore needing no artificial carbonation.)
Usually, your draught beer will be carbonated and pushed with carbon dioxide. Nitrogen, or 'beer gas', is actually a blend of both nitrogen and CO2 - about 70/30 respectively.
Before we were readily using CO2 as a serving gas, naturally carbonated beer would be hand-pumped from the barrel down to the serving tap. (These barmaids were ripped.)
As they were using air as the pusher, they were using a force that is made up of 78 per cent nitrogen. When beer gas was created to mimic the delicious serving texture of the hand-pumped cask ale, 70 per cent nitrogen seemed like a pretty decent bet.
Frequently, establishments will also use a restrictor faucet for beer gas beers. These taps have a small, penny-sized disk with five holes in it, fitted to the inside of the serving nozzle.
Nitro beer is always served under high pressure, and these small holes help knock the CO2 out of solution, creating those nice tiny bubbles that move and shake into that awesome cascading effect in your glass.
And this is where the controversy sneaks into the conversation: when we start to throw around the word 'artificial'.
Beer gas artificially creates a dense white head and smooth creamy mouthfeel and, with the addition of a restrictor, the delicate cascading bubbles.
Some people argue that bubble size, head, carbonation levels and mouthfeel should be created by the beer itself, not by the addition of a foreign carbonation/serving gas.
This got us thinking while we sipped on our creamy, thick-headed nitro IPAs. What we were interested in was whether lighter, hoppier beers brewed to style actually tasted better with the added dynamic of nitrogen.
It was time for a taste test.
Midnight Sun brewery in Anchorage came up trumps. It had on tap a nitro version of Sockeye Red IPA, which is an ale that we have drunk on CO2 numerous times, making it a great option for an informed comparison.
The verdict: not so impressed. We found that the nitrogen version of the Sockeye really lost its kick. The hop aroma was still fair, but the hop taste - the genius of this IPA - was thin.
The texture didn't blow us away either. It was certainly smooth and creamy - too creamy, heavy almost, which we were not looking for in this style of beer.
Other nitro IPAs we tried got the same sort of reaction from us – not bitter enough, with the smoothness of the beer relying on the nitro texture rather than the beer's taste.
But don't think that we are giving up – and nor should you.
If you get the chance to head into a micro, chances are they will have something light on nitro as it is pretty darn trendy right now. Try them (all), and let us know: to gas or not to gas?
Please enjoy this article responsibly.