How Inert Gas Is Used in Winemaking

Most people are aware of the large number 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 limitless. However, less commonly discussed is the utilization of specialty gases in an industry that directly involves nearly all people no matter their location- the food and beverage industry. As an example, whether you’re a wine expert or someone who likes the occasional glass at dinner, 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 protected from both oxygen and microbial spoilage during the aging process, it will probably go bad. In order to safeguard the wine, it is necessary to maintain adequate sulfur dioxide levels and keep containers full. Also, the level of protection is considerably increased by purging headspaces with inert gas in order to eliminate the oxygen. In regards to sulfur dioxide, its benefits and details about its use in this process can be found in most winemaking literature. However, while these texts may touch on purging with inert gas, they frequently do not efficiently illustrate the actual techniques needed to carry out 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 generate an efficient gas blanket to safeguard your wine. The function of this article is to explain the techniques needed to properly 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 afterwards 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 commonly known, the air we breathe is a mix of gases, roughly 20% of which is oxygen. While a constant 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, lengthy period of time, then the subsequent changes produce not wanted flaws in the wine such as a reduction of freshness, browning, sherry-like smells and taste, and acidity production. Wines exhibiting theseimperfections are referred to as oxidized, because they result from exposure to oxygen. One of the key objectives in sufficient wine aging is learning the best ways 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 it can be, 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 resist temperature changes, carboys and tanks need to 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. 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 experiences a rise in temperature, it will expand and the following pressure will end in the full force of the liquid being pushed against the lid. In some extreme spikes in temperature, this pressure could even be enough to push the tank lids out completely. If this were to take place, not only have you potentially created 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 experience temperature changes amid its storage, headspace should be left at the top of vessels.

While we now know we must leave 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 have a greater weight 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 sufficiently displaced by inert gas, and the wine can remain safe from negative reactions during its storage/aging process. The essential factor to effectively preserving the wine in this way is to be up to speed on the specific techniques needed for the proper formation of this protective blanket.

There are 3 steps recommended to form a protective inert gas blanket. The first step is protecting purity by avoiding turbulence. When employing carbon dioxide or argon to generate [[a successful|an effective|a sufficient[122] blanket, it is useful to understand that the gases readily combine 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. If this happens, the inert gas’ capacity to safeguard the wine is decreased as a result of its decreased purity. It is necessary to ensure that the delivery method makes effort 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. Typically, this means between 1-5 PSI, depending on the tubing size.

The second step to generating a protective inert gas blanket is to reach the highest volume of gas that can be delivered while still maintaining the low flow-rate required to avoid creating turbulence and therefore combining 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 requires will increase as the delivery tubing diameter decreases. If you want to quicken the process of purging without compromising the gentle flow necessary to creating a successful blanket, the diameter of the output tubing must be increased. 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 effectively creating 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. A feasible method 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 proper 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 preferred. Next, turn on the gas and initiate the purging. Lastly ,to check the oxygen levels, use a lighter and lower the flame until it is inserted just a little below the rim of the vessel. If the lighter remains lit, there is still oxygen remaining in the vessel and you should keep adding the inert gas. Keep utilizing 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 applied in winemaking, other food and beverage applications, or any other industry that utilizes specialty gases, AOC Mexico S.A. de C.V. has a plethora of products to meet all of the Mexico specialty gas needs. AOC Mexico S.A. de C.V. has a large selection of specialty gases and specialty gas equipment, along with the resources and experts on hand in Mexico to answer your questions and assist your needs. For more information, browse our online catalog or contact us via email at herrmann@aoc.com.mx or at 818-647-7427 .