Jokes aside, when you need to avoid contact with oxygen, pushing the air out and replacing it with a blanket of neutral (or inert) gas seems like a pretty logical way to go. And there are many instances where this can come in handy, whether it’s to protect a tank where wine is stored before bottling, or to flush air out from the pipes carrying wine through a pump—or even serving wine on tap.
For Thomas Perrin, of Château Beaucastel and Famille Perrin wines, in the Rhône valley, using neutral gases in the winery is just common sense. For example: “If you’re working with large tanks, you’ll need some kind of protection, in particular at stages like bottling. Just imagine if you’re halfway through a large tank that holds tens of thousands of liters, and there is half a tank left and you have to stop for some reason. Leaving the wine without protection would be highly problematic. We invested in nitrogen gas systems to resolve such problems, and it’s been extremely worthwhile.”
There can be further advantages to using neutral gases: They can reduce the need for sulfite additions. If the wine is protected by gas, it won’t need the anti-oxidative effects of SO2 quite as much. Since sulfites can sometimes have a negative impact on aromatic expression (by muting aromas, for instance), cutting down on sulfites without risking oxidation is likely to be beneficial for the wine once it reaches the consumer.
Handle with Care
Using neutral gases isn’t a simple as just opening a valve, however. It’s not because they’re neutral—in the sense that they are not particularly reactive—that they don’t have specific attributes or effects on the wine. As with everything in winemaking, care must be exerted.
For one thing, regular applications may be required if the protection is meant for the longer run. At Tawse Winery, in Niagara, Canada, winemaker Paul Pender says he uses weekly additions of argon gas on tanks to make sure they stay protected.
There can be negative side effects, depending what gases are used and in what context. For instance, if you blanket a tank with a gas mix that is low in CO2 (for instance 100% nitrogen, which is commonly used), it can actually cause CO2 to migrate from the wine into the tank headspace, causing the wine to lose some crispness.
Solutions and Dissolution
So why not just use CO2, then? It is a possibility, of course, and its low cost and accessibility make it a commonly used neutral gas in many wineries, especially smaller ones.
However, adding CO2 isn’t a magic bullet either, since CO2 is highly soluble in wine, meaning that it tends to dissolve into the wine when it is sprayed above the surface. And while too little carbon dioxide can be problematic, too much can affect the aromatics or even lead to still wines that get a bit fizzy.
That’s where argon comes in. It is far less soluble in wine, so it stays on top without entering the wine quite as much. Its downside is that it is much more rare than CO2 and nitrogen, and therefore much more expensive.
Some systems use blends of these gases, hoping to balance their advantages and disadvantages. A blend of nitrogen with some CO2, for instance, could provide proper protection without the risk of degassing. Keeping things in balance is key here as elsewhere in winemaking.
When choosing a neutral gas and deciding how often to apply it, it’s important to use what is really needed—for proper protection as well as to control costs. When “inerting” a tank, the temptation is to err on the safe side and add a significant amount of gas to be sure that the wine is protected, which might mean using more gas than necessary. The key is to regularly measure oxygen in the headspace of the tank using a suitable oxymeter (a NomaSense for instance) to ensure that neutral gases are used when needed and only in the amount needed. It can be a good way to help protect both the wine and the winery’s balance sheet.