How Inert Gas Is Used in Winemaking

Most people are aware of the variety of applications that use 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 frequently discussed is the employment 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 expert or someone who prefers the occasional glass at certain events, you may be unaware that there are some specialty gases actually are a significant factor 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 most likely spoil. In order to protect the wine, it is crucial to maintain satisfactory sulfur dioxide levels and keep containers full. Likewise, the level of protection is notably increased by purging headspaces with inert gas in order to get rid of the oxygen. In regards to sulfur dioxide, its advantages and details about its employment in this process can be found in the majority of winemaking literature. Yet, while these texts may touch on purging with inert gas, they usually do not effectively explain the actual techniques required to perform the application. First, it must be understood that it requires more than merely dispensing some argon into the headspace of your vessel in order to create an effective gas blanket to safeguard your wine. The goal of this article is to explain the techniques required to properly use inert gas to purge headspaces in order to successfully safeguard your wine. First, we will detail the significance of safeguarding your wine from coming into contact with oxygen, and after 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, around 20% of which is oxygen. While a steady supply of oxygen is vital for humans, it is certainly not beneficial when it comes to the successful 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, long 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 containing theseflaws are referred to as oxidized, because they occur as a result of exposure to oxygen. One of the key objectives in correct wine aging is learning the best methods to lower 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. 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 the liquid faces as a result of changes in temperature. Because gas is more easily compressed than liquid, it does not significantly increase the pressure in 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 is exposed to a spike in temperature, it will expand and the subsequent pressure will end 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 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 an effect of the liquid contracting. Thus, if there is a possibility 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 keep a headspace, there is still the problem of leaving room for contraction and expansion while still avoiding the negative effects of oxidative reactions. The resolution, 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 are actually heavier than air, a property that proves valuable 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 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 successful creation of this protective blanket.

There are 3 steps recommended to create a protective inert gas blanket. The first step is maintaining purity by avoiding turbulence. When utilizing carbon dioxide or argon to generate [[a successful|an effective|a sufficient[122] blanket, it is useful 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 lead to a churning effect that causes the oxygen-containing surrounding air to mix in with the inert gas. If this occurs, the inert gas’ capability to protect the wine is diminished due its decreased purity. It is vital to be sure that the delivery method attempts 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 needed to accomplish this is most often 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 thus blending the gas with the air we are attempting to get rid of. While any size tubing can employed 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 hasten the process of purging without compromising the gentle flow needed to generate a successful blanket, the diameter of the output tubing should be expanded. 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 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 leads to 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 combine all the we have discussed, the best way for purging a headspace with inert gas is as follows: First, make the adequate 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, insert 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 suggested. Next, turn on the gas and initiate the purging. Then ,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 in the vessel and you should keep inserting the inert gas. Keep employing the lighter test until the flame eventually goes out, which will indicate that there is no more oxygen.

Whether you’re seeking specialty gases to be utilized in winemaking, other food and beverage applications, or any other industry that utilizes specialty gases, Greco Gas has a plethora of products to meet all of the Pittsburgh specialty gas needs. Greco Gas has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Pittsburgh to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at info@grecogas.com or at (724) 226-3800.