How Inert Gas Is Used in Winemaking

A lot of people are aware of the multitude of applications that utilize specialty gases. From welding and cutting, to research in laboratories, to the pharmaceutical industry, the variety of uses of compressed gases seem almost limitless. However, less often discussed is the employment of specialty gases in an industry that directly affects nearly all people everywhere- the food and beverage industry. As an example, whether you’re a wine connoisseur or someone who enjoys the occasional glass at dinner time, you might not be aware 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 be spoiled. In order to safeguard the wine, it is vital to maintain satisfactory sulfur dioxide levels and keep containers full. Also, the extent 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 benefits and details about its use in this process can be read in most winemaking literature. Yet, while these texts may touch on purging with inert gas, they frequently do not sufficiently describe the actual techniques necessary to execute the application. First, it should 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 function 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 importance of safeguarding your wine from coming into contact with oxygen, and afterwards 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 generally known, the air we breathe is a mix of gases, roughly 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. 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, lengthy period of time, then the following 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 key objectives in proper wine aging is learning the best techniques 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 as full as possible, in order to get rid of headspace. Nevertheless, this approach may not always be attainable.

Unless you are storing your wine in a storage vessel that is made certain to keep the wine at a stable temperature, carboys and tanks should have a small headspace at the top in order to facilitate the contraction and expansion that occur to the liquid when the temperature changes. 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 for this 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 faces an increase in temperature, it will expand and the following pressure will lead to 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 occur, 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 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 changes amid its storage, headspace should be left at the top of vessels.

While we now know we must keep a headspace, the problem still remains 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 do not create negative reactions with the wine. In fact, carbon dioxide and argon actually weigh more than air, a property that proves beneficial to winemakers. Purging headspaces with either carbon dioxide or argon, when properly carried out, can eliminate 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 effectively displaced by inert gas, and the wine can remain safe from negative reactions during its storage/aging process. The primary factor to effectively preserving the wine in this way is to understand the specific techniques necessary for the proper formation of this protective blanket.

There are 3 steps recommended to generate a protective inert gas blanket. The first step is preserving purity by avoiding turbulence. When utilizing carbon dioxide or argon to form [[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 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’ ability to protect the wine is diminished due its decreased purity. It is vital to be sure 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 necessary to do this is most often the lowest setting on your gas regulator. Most often, 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 that is essential to avoid creating turbulence and therefore mixing the gas with the air we are trying to remove. While any size tubing can used in the delivery of a sufficient inert gas blanket, the amount of time it calls for 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 must be increased. One easy way to accomplish this is to fasten a small length of a larger diameter tube onto the existing gas line on your gas regulator.

The third and last step to properly forming 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 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 put it all together, the best way for purging a headspace with inert gas is as follows: First, make the correct adjustments on the  gas regulator to create 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, approximately 1-2 inches from the surface is suggested. 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 inserting the inert gas. Keep using the lighter test until the flame eventually subsides, 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, GTW has a plethora of products to meet all of the Western Michigan specialty gas needs. GTW has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Western Michigan to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at or at 616-754-6120.