How Inert Gas Is Used in Winemaking

Several people are familiar with the multitude of applications that employ specialty gases. From welding and cutting, to research in laboratories, to the pharmaceutical industry, the variety of uses of compressed gases seem almost immeasurable. However, less commonly discussed is the utilization of specialty gases in an industry that directly affects nearly all people worldwide- the food and beverage industry. For instance, whether you’re a wine connoisseur or someone who likes the occasional glass at dinner, you may not know that certain 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 will most likely be spoiled. In order to preserve the wine, it is necessary to maintain satisfactory sulfur dioxide levels and keep containers full. Additionally, the level of protection is considerably increased by purging headspaces with inert gas in order to remove the oxygen. In regards to sulfur dioxide, its advantages and details about its use in this process can be found in a lot of winemaking literature. However, while these texts may briefly discuss purging with inert gas, they frequently do not efficiently illustrate the actual techniques needed to execute the application. First, it must be understood that it requires more than just dispensing some argon into the headspace of your vessel in order to generate an effective gas blanket to preserve your wine. The goal of this article is to explain the techniques necessary to effectively use inert gas to purge headspaces in order to successfully protect your wine. First, we will detail the significance 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, approximately 20% of which is oxygen. While a steady supply of oxygen is necessary for humans, it is certainly not beneficial when it comes to the proper storage of most wines. This is because 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 resulting changes create undesireable flaws in the wine such as a decrease of freshness, browning, sherry-like smells and taste, and acidity production. Wines possessing theseflaws are referred to as oxidized, since they occur upon exposure to oxygen. One of the key objectives in sufficient wine aging is learning the best techniques to reduce the wine’s oxygen exposure in order to avert oxidation. One easy method to do so is to fill the wine’s storage vessel as full as possible, in order to eliminate headspace. Nevertheless, this technique may not always be feasible.

Unless you are storing your wine in a storage vessel that is assured to maintain temperature stability, carboys and tanks should 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 faces an increase in temperature, it will expand and the following 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 fully. 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 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 likelihood that your wine could face temperature fluctuations amid its storage, headspace should be left at the top of vessels.

While we now know we must keep a headspace, there is still the problem 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 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 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 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 aware of the specific techniques needed for the effective generation 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 employing carbon dioxide or argon to generate [[a successful|an effective|a sufficient[122] blanket, it is significant to understand that the gases readily mix with each other when moved. When seeking 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 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’ capability to preserve the wine is reduced because of its decreased purity. It is essential to make 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 has a minimum amount of oxygen. The ideal flow rate necessary to do 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 reach the highest volume of gas that can be delivered while still maintaining the low flow-rate that is vital to avoid creating turbulence and hence mixing the gas with the air we are attempting to eliminate. While any size tubing can utilized in the delivery of an adequate inert gas blanket, the amount of time it needs 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. A simple way to achieve 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 directing the flow of gas directly at the surface. This will have the effect of the inert gas being less likely to mix 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 adequate 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, roughly 1-2 inches from the surface is recommended. Next, turn on the gas and initiate the purging. Finally ,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 adding the inert gas. Keep using the lighter test until the flame eventually extinguishes, which will reveal that there is no longer oxygen in the vessel.

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, American Welding & Gas, Inc. has a plethora of products to meet all of the Indianapolis specialty gas needs. American Welding & Gas, Inc. has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Indianapolis to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at peter.vanslyke@amwelding.com or at .