How Inert Gas Is Used in Winemaking

Several people have heard about the variety of applications that use specialty gases. From welding and cutting, to research in laboratories, to the pharmaceutical industry, the uses and applications of compressed gases seem almost limitless. However, less commonly discussed is the employment of specialty gases in an industry that directly affects nearly all people no matter their location- the food and beverage industry. As an example, whether you’re a wine aficionado or someone who likes the occasional glass at dinner time, you might not be aware that there are some specialty gases actually are a significant factor in the process of making wine.

If a wine is not constantly protected from both oxygen and microbial spoilage during the aging process, it is likely to be spoiled. In order to safeguard the wine, it is crucial to maintain satisfactory sulfur dioxide levels and keep containers full. Also, the amount of protection is significantly increased by purging headspaces with inert gas in order to get rid of the oxygen. In regards to sulfur dioxide, its advantages and details about its use in this process can be read in a lot of winemaking literature. However, while these texts may touch on purging with inert gas, they frequently do not effectively explain the actual techniques required to perform the application. First, it needs to be understood that it requires more than merely dispensing some argon into the headspace of your vessel in order to generate a sufficient gas blanket to preserve your wine. The purpose of this article is to explain the techniques needed to adequately use inert gas to purge headspaces in order to successfully preserve your wine. First, we will discuss the significance of safeguarding your wine from coming into contact with oxygen, and afterwards we will explain the precise gas purging methods necessary to do so.

The space in a barrel or tank that is not filled by liquid is filled by gas. As is generally known, the air we breathe is a blend of gases, roughly 20% of which is oxygen. While a steady supply of oxygen is vital for humans, it is certainly not beneficial when it comes to the successful storage of most wines. The reason for this is that a series of chemical changes occur to wine when exposed to oxygen. If wine is exposed to oxygen for an uncontrolled, extended period of time, then the subsequent changes create undesireable flaws in the wine such as a diminishing of freshness, browning, sherry-like smells and taste, and acidity production. Wines containing theseimperfections are referred to as oxidized, since they occur upon exposure to oxygen. One of the main objectives in proper wine aging is learning the best ways to lower the wine’s oxygen exposure in order to prevent oxidation. One easy method to do so is to fill the wine’s storage vessel as full as possible, in order to remove headspace. Nevertheless, this approach may not always be possible.

Unless you are storing your wine in a storage vessel that is made certain to maintain temperature stability, carboys and tanks need to have a small headspace at the top in order to facilitate the contraction and expansion that occur to the liquid when the temperature changes. Because gas iscompressed more easily than liquid, it does not significantly increase the pressure in the storage unit if there is some space left at the top. It is because of this that you find a quarter-of-an-inch space below the cork in a new bottle of wine. If there is no headspace and the wine is exposed to a rise in temperature, it will expand and the following pressure will lead to the full force of the liquid being pushed against the lid. In some extreme spikes in temperature, this pressure could even be enough to push the tank lids out completely. If this were to occur, not only have you potentially created a mess and lost wine, but your wine is now exposed to elements that could lead to its spoiling. In an extreme temperature decline, on the other hand, the lids would be pulled inward as a consequence of the liquid contracting. Thus, if there is a chance that your wine could be exposed to temperature variations amid its storage, headspace should be left at the top of vessels.

While we now know we must keep a headspace, the problem still remains of leaving room for contraction and expansion while simultaneously avoiding the negative effects of oxidative reactions. The answer, however, is found by replacing the headspace air that contains oxygen with an inert gas, such as argon, nitrogen, or carbon dioxide. These gases, unlike oxygen, do not do not create negative reactions with the wine. In fact, carbon dioxide and argon actually weigh more than air, a property that proves valuable to winemakers. Purging headspaces with either carbon dioxide or argon, when properly executed, can get rid of oxygen by lifting it up and extracting it from the storage vessel, similar to how oil can float on the surface of water. The oxygen in the vessel has now been effectively displaced by inert gas, and the wine can remain safe from negative reactions during its storage/aging process. The essential factor to correctly safeguarding the wine in this way is to be up to speed on the specific techniques needed for the successful creation of this protective blanket.

There are 3 steps recommended to create a protective inert gas blanket. The first step is preserving purity by avoiding turbulence. When employing carbon dioxide or argon to generate [[a successful|an effective|a sufficient[122] blanket, it is essential to know that the gases readily mix with each other when moved. When trying to purge headspaces with inert gas, the purity of the final volume of the gas is determined by the gas’s flow rate as it exits the tubing. Larger flow rates lead to the creation of a churning effect that causes the oxygen-containing surrounding air to mix in with the inert gas. If this occurs, the inert gas’ capacity to protect the wine is reduced because of its decreased purity. It is necessary to ensure that the delivery method tries to avoid turbulence as much as possible in order to have a pure layer of inert gas that is lacking oxygen. The ideal flow rate necessary to do this is typically the lowest setting on your gas regulator. Usually, this means between 1-5 PSI, depending on the tubing size.

The second step to generating a protective inert gas blanket is to find the highest volume of gas that can be delivered while still maintaining the low flow-rate that is essential to avoid creating turbulence and thus mixing the gas with the air we are attempting to eliminate. While any size tubing can utilized in the delivery of an effective inert gas blanket, the amount of time it needs will increase as the delivery tubing diameter decreases. If you want to hasten the process of purging without compromising the gentle flow necessary to creating a successful blanket, the diameter of the output tubing should be expanded. A simple way to achieve this is to fasten a small length of a larger diameter tube onto the existing gas line on your gas regulator.

The third and final step to effectively creating an inert gas blanket is to have the gas flow parallel to the surface of the wine, or laminar, instead of pointing the flow of gas directly at the surface. This leads to the inert gas being less likely to combine with the surrounding air when being delivered because it will not bounce off the surface of the liquid. An effective and easy way to do so is to attach a diverter at the end of the gas tubing.

To wrap up everything we have learned, the recommended method for purging a headspace with inert gas is as follows: First, make the proper adjustments on the  gas regulator to find a flow rate that is as high as possible while still maintaining a gentle, low-pressure flow. Then, insert the tubing into the storage vessel and arrange it so that the output is close to the surface of the wine, roughly 1-2 inches from the surface is preferred. Next, turn on the gas and initiate the purging. Then ,to check the oxygen levels, use a lighter and lower the flame until it is inserted just a little below the rim of the vessel. If the lighter remains lit, there is still oxygen remaining in the vessel and you should keep dispensing the inert gas. Keep utilizing the lighter test until the flame eventually subsides, which will illustrate that the oxygen is gone.

Whether you’re in search of specialty gases to be employed in winemaking, other food and beverage applications, or any other industry that utilizes specialty gases, A-OX Welding Supply has a plethora of products to meet all of the Sioux Falls specialty gas needs. A-OX Welding Supply has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Sioux Falls to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at or at 605-336-1125.