How Inert Gas Is Used in Winemaking

Several people are aware of the large number of applications that call for specialty gases. From welding and cutting, to research in laboratories, to the pharmaceutical industry, the widespread employment of compressed gases seem almost unending. However, less commonly discussed is the employment of specialty gases in an industry that directly involves nearly all people worldwide- the food and beverage industry. For example, whether you’re a wine expert or someone who likes the occasional glass at dinner time, you may not know that certain 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 will probably be spoiled. In order to protect the wine, it is important to maintain adequate sulfur dioxide levels and keep containers full. Additionally, the extent of protection is notably increased by purging headspaces with inert gas in order to remove 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 mention purging with inert gas, they usually do not effectively explain the actual techniques required to perform the application. First, it needs to be understood that it requires more than simply dispensing some argon into the headspace of your vessel in order to implement a sufficient gas blanket to safeguard your wine. The purpose of this article is to discuss the techniques necessary to effectively use inert gas to purge headspaces in order to successfully safeguard your wine. First, we will touch on the significance of safeguarding your wine from coming into contact with oxygen, and after we will explain the precise gas purging methods needed 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, about 20% of which is oxygen. While a consistent supply of oxygen is vital for humans, it is certainly not beneficial when it comes to the proper storage of most wines. The explanation 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 following changes produce undesireable flaws in the wine such as a reduction of freshness, browning, sherry-like smells and taste, and acidity production. Wines exhibiting theseflaws 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 reduce 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 remove headspace. However, this method may not always be attainable.

Unless you are storing your wine in a storage vessel that is assured to keep the wine at a stable temperature, 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 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 spike in temperature, it will expand and the subsequent pressure will lead to 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 fully. If this were to take place, not only have you potentially caused a mess and lost wine, but your wine is now exposed to elements that could cause it to spoil. 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 face temperature changes throughout its storage, headspace should be left at the top of vessels.

While we now know we must leave a headspace, we still are left with the problem of leaving room for contraction and expansion while at the same time 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 weigh more than air, a property that proves advantageous to winemakers. Purging headspaces with either carbon dioxide or argon, when properly executed, 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 sufficiently displaced by inert gas, and the wine can remain safe from negative effects during its storage/aging process. The primary factor to effectively safeguarding the wine in this way is to be up to speed on the specific techniques required for the effective generation 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 using carbon dioxide or argon to form [[a successful|an effective|a sufficient[122] blanket, it is significant to know that the gases readily combine with each other when moved. When seeking 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. Larger 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 protect the wine is diminished due its decreased purity. It is essential to make sure that the delivery method attempts 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 generally 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 attain the highest volume of gas that can be delivered while still maintaining the low flow-rate that is vital to avoid creating turbulence and therefore blending the gas with the air we are attempting to get rid of. While any size tubing can employed 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 made larger. A simple way to achieve 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 aiming the flow of gas directly at the surface. This will have the effect of the inert gas being less likely to blend 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 correct adjustments on the  gas regulator to determine 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 best. Next, turn on the gas and initiate the purging. Lastly ,to check the oxygen levels, use a lighter and lower the flame until it reaches just below the rim of the vessel. If the lighter remains lit, there is still oxygen inside the vessel and you should keep dispensing the inert gas. Keep employing the lighter test until the flame eventually subsides, which will indicate that there is no more oxygen.

Whether you’re needing specialty gases to be utilized in winemaking, other food and beverage applications, or any other industry that utilizes specialty gases, WestAir Specialty Gases and Equipment has a plethora of products to meet all of the Southern California specialty gas needs. WestAir Specialty Gases and Equipment has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Southern California to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at info@westairgases.com or at 866-WESTAIR.