How Inert Gas Is Used in Winemaking

A lot of people are familiar with the large number of applications that utilize specialty gases. From welding and cutting, to research in laboratories, to the pharmaceutical industry, the uses and applications of compressed gases seem almost unending. However, less often discussed is the use of specialty gases in an industry that directly affects nearly all people everywhere- the food and beverage industry. For instance, whether you’re a wine expert or someone who likes the occasional glass at certain events, you may be unaware that some specialty gases actually have a significant impact 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 important to maintain sufficient sulfur dioxide levels and keep containers full. Additionally, the level of protection is significantly increased by purging headspaces with inert gas in order to remove the oxygen. In regards to sulfur dioxide, its beneficial uses and details about its utilization in this process can be found in the majority 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 should be understood that it requires more than simply dispensing some argon into the headspace of your vessel in order to generate a sufficient gas blanket to safeguard your wine. The function of this article is to discuss the techniques needed to properly use inert gas to purge headspaces in order to successfully protect your wine. First, we will mention the importance of safeguarding your wine from being exposed to oxygen, and later 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 widely known, the air we breathe is a blend of gases, roughly 20% of which is oxygen. While a constant supply of oxygen is necessary 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, lengthy period of time, then the following changes create unwanted flaws in the wine such as a reduction of freshness, browning, sherry-like smells and taste, and acidity production. Wines exhibiting theseimperfections are referred to as oxidized, because they result from exposure to oxygen. One of the primary objectives in sufficient wine aging is learning the best ways to decrease the wine’s oxygen exposure in order to prevent oxidation. One easy method to do so is to fill the wine’s storage vessel to its full capacity, in order to eliminate headspace. Nevertheless, this technique may not always be attainable.

Unless you are storing your wine in a storage vessel that is made certain to resist temperature changes, carboys and tanks must have a small headspace at the top in order to facilitate the contraction and expansion that the liquid faces as a result of changes in temperature. Because gas iscompressed more easily than liquid, it does not add significant pressure to the storage unit if there is some space left at the top. It is for this reason 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 experiences an increase 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 entirely. If this were to occur, not only have you potentially made a mess and lost wine, but your wine is now exposed to elements that could cause it to spoil. In an extreme temperature decrease, on the other hand, the lids would be pulled inward as a result of the liquid contracting. Thus, if there is a possibility that your wine could experience temperature fluctuations throughout its storage, headspace should be left at the top of vessels.

While we now know we must keep a headspace, we still are left with the problem of leaving room for contraction and expansion while still 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 performed, can eliminate 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 properly displaced by inert gas, and the wine can remain safe from negative reactions during its storage/aging process. The essential factor to effectively safeguarding the wine in this way is to understand the specific techniques required for the effective generation of this protective blanket.

There are 3 steps that are helpful to form a protective inert gas blanket. The first step is protecting purity by avoiding turbulence. When employing carbon dioxide or argon to generate [[a successful|an effective|a sufficient[122] blanket, it is useful to know that the gases readily mix with each other when moved. When attempting to purge headspaces with inert gas, the gas’s flow rate as it exits the tubing acts as the determining factor in the purity of the final volume of gas. Greater flow rates generate a churning effect that causes the oxygen-containing surrounding air to mix in with the inert gas. If this happens, the inert gas’ capability to preserve the wine is diminished due its decreased purity. It is vital to be sure that the delivery method makes effort 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 usually the lowest setting on your gas regulator. Most often, this means between 1-5 PSI, depending on the tubing size.

The second step to forming a protective inert gas blanket is to find the highest volume of gas that can be delivered while still maintaining the low flow-rate needed to avoid creating turbulence and therefore blending the gas with the air we are attempting to get rid of. While any size tubing can used in the delivery of an effective inert gas blanket, the amount of time it calls for will increase as the delivery tubing diameter decreases. If you want to speed up the process of purging without compromising the gentle flow necessary to creating a successful blanket, the diameter of the output tubing should be made larger. One way to easily do this is to connect 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 directing the flow of gas directly at the surface. This results in 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. A feasible method to do so is to attach a diverter at the end of the gas tubing.

To combine all the we have discussed, the suggested method for purging a headspace with inert gas is as follows: First, make the proper adjustments on the  gas regulator to generate a flow rate that is as high as possible while still maintaining a gentle, low-pressure flow. Then, lower the tubing into the storage vessel and arrange it so that the output is close to the surface of the wine, approximately 1-2 inches from the surface is best. Next, turn on the gas and initiate the purging. Finally ,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 inside the vessel and you should keep inserting the inert gas. Keep utilizing the lighter test until the flame eventually goes out, which will reveal that there is no longer oxygen in the vessel.

Whether you’re seeking specialty gases to be employed in winemaking, other food and beverage applications, or any other industry that utilizes specialty gases, Weldstar has a plethora of products to meet all of the Northern Illinois specialty gas needs. Weldstar has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Northern Illinois to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at starrant@weldstar.com or at 855-998-4875.