Friday, September 9, 2011

Argon beer, an alternative to the usual CO2 carbonation



Most beer is carbonated with 100% CO2. Some beers, notably Guinness and some other porter/stouts, contain a mixture of nitrogen and CO2 in a ratio commonly 75/25 N2/CO2. The nitrogen is less soluble in water, and allows the beer to be served at a higher pressure without dissolving too much gas into the beer itself. The higher serving pressure churns up the beer as it exits the spout, and creates a creamy head that is the signature of a good Guinness pour. Some pubs use 75/25 gas to push normally carbonated beers out of the tap, but the beers themselves contain only CO2.

In this video I wondered what would happen if I used argon instead of nitrogen. I started by using %100 argon since the solubility of Ar is between that of N2 and CO2. As it turns out, the Ar is not soluble enough to produce a decent head on the beer. Additionally, the complete lack of CO2 makes the beer taste sweet (like it's flat) since the CO2 is necessary to form carbonic acid in water, and this is an important flavor component of beer.

Xenon has anesthetic properties at atmospheric pressure, while the other noble gasses can become anesthetic at higher pressures. Does anyone want to explore xenon beer, or have any experience with xenon used as an anesthetic?

6 comments:

Anonymous said...

You weren't worried about it bursting when you were pressure testing?

Ben Krasnow said...

Anonymous, I wasn't too worried. It's only 50 psi, and the stainless certainly can handle it. I suppose the threads on the cap/neck might slip past each other, but the fit is actually fairly tight.

Anonymous said...

Cool experiment! Looking forward to the follow up with co2.

Couple of comments.
When I carbonate my kegs, it takes 2 weeks at pressure for the co2 to properly stay in the beer (I'm sure there is a better term for that). My limited understanding from homebrewing is that the absorption of the co2 into the liquid is a function of contact space, volume (pressure) and time. How long are you leaving the argon in the beer?

I would expect the pressure drop to be from the temperature drop in the fridge.

Nice fermentor BTW

Keep up the good work!

Patrick said...

What about a Helium-Beer next time ;-) ?

MordecaiV said...

Ben, I'm not an expert by any means, but my understanding was that after the pouring very little nitrogen is anywhere but the head. I think the "widget" and the tap structure are key components, and that a full nitrogen beer would taste more flat than your Ar beer, as nitrogen is even less soluble than Ar. I think you'll need some kind of micro agitation happening when you release the pressure, or you'll just have low-carbonated beer with a nice atmosphere of argon.

nitrous said...

gas absorption is also a function of temperature. At colder temperatures, more gas is solubilized into the liquid so, to dissolve the most gas into a liquid, make sure it is as cold as possible.
This is Henry's Law and explains why carbonated beverages, under pressure 'fiz up' as soon as that pressure is released. Warm soda fizzes a lot more than cold soda does.

Doug

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