How Inert Gas Is Used in Winemaking

Many people are aware of the variety of applications that call for specialty gases. From welding and cutting, to research in laboratories, to the pharmaceutical industry, the uses and applications of compressed gases seem almost immeasurable. However, less commonly discussed is the employment 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 connoisseur or someone who prefers the occasional glass at dinner time, you may be unaware that some specialty gases actually are a significant factor in the process of making wine.

If a wine is not protected from both oxygen and microbial spoilage during the aging process, it is likely to go bad. In order to protect the wine, it is vital to maintain satisfactory sulfur dioxide levels and keep containers full. Additionally, the level of protection is notably increased by purging headspaces with inert gas in order to eliminate the oxygen. In regards to sulfur dioxide, its benefits and details about its use in this process can be seen in most winemaking literature. Yet, while these texts may mention purging with inert gas, they usually do not efficiently explain the actual techniques required to carry out the application. First, it must be understood that it requires more than simply dispensing some argon into the headspace of your vessel in order to implement an effective gas blanket to safeguard your wine. The purpose of this article is to describe the techniques required to adequately 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 required to do so.

The space in a barrel or tank that is not filled by liquid is filled by gas. As is commonly known, the air we breathe is a blend of gases, roughly 20% of which is oxygen. While a consistent 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, long period of time, then the resulting changes generate undesireable flaws in the wine such as a decrease of freshness, browning, sherry-like smells and taste, and acidity production. Wines exhibiting theseunwanted characteristics are referred to as oxidized, since they occur upon exposure to oxygen. One of the key objectives in proper wine aging is learning the best methods to lower the wine’s oxygen exposure in order to avert oxidation. One easy method to do so is to fill the wine’s storage vessel to its full capacity, in order to get rid of headspace. Unfortunately, this method may not always be attainable.

Unless you are storing your wine in a storage vessel that is assured 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 is more easily compressed than liquid, it does not add a lot of pressure the storage unit if there is some space left at the top. This is the 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 a spike in temperature, it will expand and the resulting pressure will end in the full force of the liquid being pushed against the lid. In some extreme rises 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 caused 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 result of the liquid contracting. Thus, if there is a possibility that your wine could be exposed to temperature fluctuations throughout its storage, headspace should be left at the top of vessels.

While we now know we must have a headspace, there is still the problem 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 negatively react with wine. In fact, carbon dioxide and argon actually have a greater weight than air, a property that proves advantageous to winemakers. Purging headspaces with either carbon dioxide or argon, when properly carried out, can rid the vessel of oxygen by lifting it up and eliminating 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 ramifications during its storage/aging process. The primary factor to correctly protecting the wine in this way is to understand the specific techniques necessary for the effective generation of this protective blanket.

There are 3 steps suggested to form a protective inert gas blanket. The first step is maintaining purity by avoiding turbulence. When employing carbon dioxide or argon to form [[a successful|an effective|a sufficient[122] blanket, it is significant to be aware that the gases readily blend with each other when moved. When attempting 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. Greater flow rates generate a churning effect that causes the oxygen-containing surrounding air to mix in with the inert gas. In this scenario, the inert gas’ capacity to safeguard the wine is decreased as a result 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 has a minimum amount of oxygen. The ideal flow rate required to succeed in doing this is most often the lowest setting on your gas regulator. Usually, this means between 1-5 PSI, depending on the tubing size.

The second step to creating 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 thus mixing the gas with the air we are attempting to eliminate. While any size tubing can utilized in the delivery of a sufficient 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 necessary to creating a successful blanket, the diameter of the output tubing must be increased. One easy way to accomplish this is to attach a small length of a larger diameter tube onto the existing gas line on your gas regulator.

The third and final 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 will have the effect of 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 simple and correct method 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 adequate 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, lower 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 suggested. Next, turn on the gas and initiate the purging. Lastly ,to check the oxygen levels, use a lighter and lower the flame until it enters the vessel just barely below the rim. If the lighter remains lit, there is still oxygen inside the vessel and you should keep dispensing the inert gas. Keep using the lighter test until the flame eventually goes out, which will illustrate that the oxygen is gone.

Whether you’re looking for specialty gases to be employed in winemaking, other food and beverage applications, or any other industry that utilizes specialty gases, Mississippi Welders Supply Co., Inc. has a plethora of products to meet all of the Winona specialty gas needs. Mississippi Welders Supply Co., Inc. has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Winona to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at winona@mwsco.com or at (507) 454-5231.