www.nthba.org

what is beer gas vs co2? pontificate..

It's a mixture of CO2 and nitrogen, I can't remember what the percentages of each are. I don't know anyplace you can purchase it around here however so I have never messed with it. That stuff does however dumb down the flavor or many beers so if you use it, you need to reformulate your recipes to take that into account. The real ale guys over in the UK see that as pretty "slutty" by the way, I'm sure Scott would have something to say about all that.

the reason I ask, I was at a restaurant openning, the taps weren't working because the co2 tank was empty... unfortunately mine was too... he said that the vendors are pushing the beer gas ... I hadn't heard of it... so I'm asking..

We heard a talk about beer gas at NHC. It is a mixture that Guinness created for their beer. It should not be used for anything other than Guinness. If it is used on regular beer the beer will become flat. The vendors push it because it is easy but wrong.

thanks Jimmy, just what I wanted to know... I've passed the info along..

From Wikipedia:

In modern beer dispensing, a metal keg is pressurised with carbon dioxide (CO2) gas or nitrogen (N2) gas or a combination of both. Pressure in the keg drives the beer to the dispensing tap, or faucet.

Pressurised CO2 in the keg's headspace maintains carbonation in the beer. The CO2 pressure varies depending on the amount of CO2 already in the beer and the keg storage temperature. Occasionally the CO2 gas is blended with nitrogen gas. CO2 / nitrogen blends are used to allow a higher operating pressure in complex dispense systems.

Nitrogen is used under high pressure when dispensing dry stouts (such as Guinness) and other creamy beers because it displaces CO2 to (artificially) form a rich tight head and a less carbonated taste. This makes the beer feel smooth on the palate and gives a foamy appearance. Premixed bottled gas for creamy beers is usually 75% nitrogen and 25% CO2. This premixed gas which only works well with creamy beers is often referred to as Guinness Gas, Beer Gas, or Aligal. Using "Beer Gas" with other beer styles can cause the last 5% to 10% of the beer in each keg to taste very flat and lifeless.

Note: From the class at NHC I believe they were suggesting that much more than the last 5-10 percent of the keg will be flat.

And the reason that the beer tastes less carbonated is because it is. Nitrogen is not very soluable in beer so it comes out of solution very quickly (causing the cascading effect you see in a glass of Guiness, it is also resonsible for the creamy head). As the headspace gets bigger in the keg (as it is emptied), more and more CO2 comes out of solution in the keg (causing the beer to become less and less carbonated). Since the beer has less CO2 to begin with (the majority of the pressure in the keg is related to the nitrogen) as the keg is emptied the beer contains less and less CO2 and gets pretty flat near the end. Review your basic college chemistry, specifically Boyles Law of Gasses and all will be revealed.

I would personally rather see bars put in hand pumps, even if they need to use a cask breather to make the beer last longer. I would just love to have one of those things at home but they are very expensive relative to regular CO2 systems and somewhat more trouble to maintain. Based on poking around on the internet, I estimate it would cost about $1,000 to get one of those set ups and run it correctly. You would need a dedicated frige since you generally want to serve "real ale" at around 55F or so, otherwise the carbonation would become too high and cause problems with the dispense using a hand pump.

Here ya go Bill,

Invite me over when it is done.

http://www.northernbrewer.com/brewing/k ... -unit.html