How Inert Gas Is Used in Winemaking

Many 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 widespread employment of compressed gases seem almost unending. However, less frequently discussed is the employment of specialty gases in an industry that directly pertains to nearly all people no matter their location- the food and beverage industry. For instance, whether you’re a wine connoisseur or someone who likes the occasional glass at certain events, you may be unaware 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 will most likely spoil. In order to safeguard 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 read in most winemaking literature. Nonetheles, while these texts may touch on purging with inert gas, they usually do not effectively illustrate the actual techniques needed to execute the application. First, it needs to be understood that it requires more than just dispensing some argon into the headspace of your vessel in order to implement an efficient gas blanket to preserve your wine. The function of this article is to discuss the techniques necessary to adequately use inert gas to purge headspaces in order to successfully preserve your wine. First, we will discuss the significance 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, about 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 safe 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 resulting changes create undesireable flaws in the wine such as a diminishing 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 primary objectives in correct 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 technique may not always be attainable.

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 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 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 result 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 happen, 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 experience 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 at the same time 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 have negative impacts on the wine. In fact, carbon dioxide and argon are actually heavier than air, a property that proves beneficial 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 key to effectively safeguarding the wine in this way is to understand the specific techniques required for the effective generation of this protective blanket.

There are 3 steps suggested to create 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 know that the gases readily combine with each other when moved. When seeking to purge headspaces with inert gas, the determining factor in the purity of the final volume of gas is the gas’s flow rate as it exits the tubing. 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 safeguard 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 contains little 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 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 thus combining the gas with the air we are attempting to get rid of. While any size tubing can used in the delivery of a sufficient inert gas blanket, the amount of time it needs will increase as the delivery tubing diameter decreases. If you want to shorten the process of purging without compromising the gentle flow needed to generate a successful blanket, the diameter of the output tubing must be increased. 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 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 best way for purging a headspace with inert gas is as follows: First, make the correct 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, place 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 best. 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 in the vessel and you should keep adding 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 seeking specialty gases to be used in winemaking, other food and beverage applications, or any other industry that utilizes specialty gases, Elite Air has a plethora of products to meet all of the Riverside specialty gas needs. Elite Air has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Riverside to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at info@cal-tool.com or at (951) 686-7822.