How Inert Gas Is Used in Winemaking

Most people are aware of 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 limitless. However, less commonly discussed is the use of specialty gases in an industry that directly involves nearly all people worldwide- the food and beverage industry. As an example, whether you’re a wine expert or someone who enjoys the occasional glass at dinner time, you may not know that certain specialty gases actually play a very important role in the process of making wine.

If a wine does not remain constantly protected from both oxygen and microbial spoilage during the aging process, it is likely to go bad. In order to preserve the wine, it is crucial to maintain adequate sulfur dioxide levels and keep containers full. Additionally, the amount of protection is considerably increased by purging headspaces with inert gas in order to eliminate the oxygen. In regards to sulfur dioxide, its advantages and details about its utilization in this process can be read in a lot of winemaking literature. Nonetheles, while these texts may touch on purging with inert gas, they frequently do not sufficiently illustrate the actual techniques needed to carry out the application. First, it should be understood that it requires more than merely dispensing some argon into the headspace of your vessel in order to implement an effective gas blanket to safeguard your wine. The function of this article is to describe the techniques needed to effectively use inert gas to purge headspaces in order to successfully safeguard your wine. First, we will discuss the priority of safeguarding your wine from being exposed to oxygen, and after 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 mixture of gases, about 20% of which is oxygen. While a constant supply of oxygen is crucial 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 produce not wanted flaws in the wine such as a decrease of freshness, browning, sherry-like smells and taste, and acidity production. Wines possessing theseunwanted characteristics are referred to as oxidized, since they occur upon exposure to oxygen. One of the primary objectives in sufficient wine aging is learning the best techniques 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 as full as possible, in order to get rid of headspace. Unfortunately, this method 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 must have a small headspace at the top in order to facilitate the contraction and expansion that that the liquid experiences as a result of temperature fluctuations. Because gas iscompressed more easily than liquid, it does not add a lot of pressure 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 experiences a rise in temperature, it will expand and the subsequent pressure will result in the full force of the liquid being pushed against the lid. In some extreme increases in temperature, this pressure could even be enough to push the tank lids out completely. If this were to take place, not only have you potentially made a mess and lost wine, but your wine is now exposed to elements that could cause spoilage. 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 likelihood that your wine could face temperature fluctuations during its storage, headspace should be left at the top of vessels.

While we now know we must leave a headspace, the problem still remains of leaving room for contraction and expansion while simultaneously avoiding the negative effects of oxidative reactions. The solution, 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 are actually heavier than air, a property that proves beneficial to winemakers. Purging headspaces with either carbon dioxide or argon, when properly executed, 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 effectively displaced by inert gas, and the wine can remain safe from negative effects during its storage/aging process. The key to effectively 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 that are helpful to generate a protective inert gas blanket. The first step is maintaining purity by avoiding turbulence. When utilizing carbon dioxide or argon to create [[a successful|an effective|a sufficient[122] blanket, it is useful to be aware that the gases readily mix with each other when moved. When trying 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. Higher flow rates lead to the creation of a churning effect that causes the oxygen-containing surrounding air to mix in with the inert gas. In this scenario, the inert gas’ ability to preserve the wine is diminished due its decreased purity. It is necessary to ensure that the delivery method makes effort to avoid turbulence as much as possible in order to have a pure layer of inert gas that has a minimum amount of oxygen. The ideal flow rate needed to accomplish this is typically the lowest setting on your gas regulator. Typically, this means between 1-5 PSI, depending on the tubing size.

The second step to forming a protective inert gas blanket is to attain the highest volume of gas that can be delivered while still maintaining the low flow-rate required to avoid creating turbulence and thus blending the gas with the air we are attempting to get rid of. While any size tubing can applied in the delivery of an adequate inert gas blanket, the amount of time it requires will increase as the delivery tubing diameter decreases. If you want to speed up the process of purging without compromising the gentle flow required to form a successful blanket, the diameter of the output tubing should be made larger. One easy way to accomplish this is to connect a small length of a larger diameter tube onto the existing gas line on your gas regulator.

The third and concluding step to correctly generating 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 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. An effective and easy way to do so is to attach a diverter at the end of the gas tubing.

To combine all the we have discussed, the recommended method for purging a headspace with inert gas is as follows: First, make the correct 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, 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 recommended. Next, turn on the gas and initiate the purging. Lastly ,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 using the lighter test until the flame eventually extinguishes, which will illustrate that the oxygen is gone.

Whether you’re seeking specialty gases to be employed in winemaking, other food and beverage applications, or any other industry that utilizes specialty gases, Coastal Welding Supply has a plethora of products to meet all of the Beaumont specialty gas needs. Coastal Welding Supply has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Beaumont to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at jcmazoch@coastalws.com or at 800-852-4177.