We supply three types of inert gas: nitrogen (N2) (with a fraction of argon (Ar) mixed in - 11.6% by volume), pure argon (99.99%), and food-grade CO2. For wines and spirits, we recommend N2. Some of our customers prefer CO2 for white wines, which helps to keep these wines bright and crisp.
One thing to keep in mind when putting wine and spirits under inert gas is that these liquids readily absorb gases that aren't already in solution. For example, an unopened bottle of wine has essentially zero percent dissolved oxygen (O2). Any O2 that made it into the bottle during filling, and over time as ingress through the cork, will have reacted with sulphur dioxide or the wine compounds. This is why a bottle of wine opened to the atmosphere will immediately start absorbing O2. Contrary to popular belief, reactions with O2 take time - hours to days, but absorption can happen quickly, especially if there's agitation.
N2, the largest component of the atmosphere at 78% by volume, is inert at room temperature with respect to wine, and remains in solution at a saturated concentration from the time the wine is a grape to when it's fully matured in a bottle. The only way to get more N2 into solution is to increase its partial pressure and/or lower the solution temperature.
Argon, on the other hand, only constitutes 1% of the atmosphere, which means that it is not normally found in solution at any significant concentration in grapes. Argon sparging is rare in winemaking, which means that most wines have essentially no concentration of dissolved argon. So any argon introduced into a bottle of wine, will be soaked up like a sponge, increasingly so as the pressure increases. While it’s true that argon does not react with wine compounds due to it being extremely inert, dissolved argon can soften older more fragile wines, essentially decanting the wine in the bottle. This may or may not be desired.
This is why we prefer N2 to serve and preserve wine. Simply put, N2, in concert with the Pungo’s low operating pressure of 1-2 psi, does the best job of leaving the wine's delicate chemistry intact.;