Controlling the oxygen level in wine is critical to the winemaking process. Too much oxygen can result in a shorter shelf life, color loss or browning, a shift from fresh and fruity to off-note aromas, a flat taste, and a thin, lackluster mouthfeel. Too little oxygen can lead to stuck fermentations, sulfury off-tastes, tannins that fail to soften, underdeveloped aromas, and a lack of complexity.

The winemaker's solution is to eliminate oxygen in different stages of the winemaking process, including sparging, transferring the wine, and bottling. In sparging, nitrogen gas is bubbled through the wine to remove any suspended oxygen in the liquid. In the transfer process, nitrogen pushes the wine from vessel to vessel or into the final packaging. In bottling, nitrogen evacuates oxygen from the bottle's headspace to extend the wine's shelf life. There are many other applications, making nitrogen gas an essential tool in the cellar.

Shrinking Nitrogen's Cost

"The #1 concern when wineries contact Atlas is to reduce their nitrogen costs," says Carter Thiel, Product Marketing Manager at Atlas Copco. "We save our winery customers an average of 75% of their nitrogen generation costs by installing one of our systems for on-site generation."

Large California wineries with continuous around-the-clock nitrogen gas usage can save as much as $15,000 a month—$180,000 annually—by transitioning from delivered bulk gas to generating it on-site. Savings that significant rack up quickly, allowing the winery to pay for the capital expense outlay for the on-site system in just over a year. After that, the only costs are maintenance, upkeep, and utility bills for the energy used.

Wineries' nitrogen needs vary depending on their production output, winemaking protocols, and nitrogen purity requirements. One of the drawbacks of buying nitrogen from a gas company is that wineries end up paying for the 99.99% purity that most gas companies produce. While a high 99.9% nitrogen purity level is best when racking tanks to remove the leaves after fermentation or sparging to remove dissolved oxygen, not all winery protocols require it. For example, 95% or even lower purity can be sufficient for blanketing tanks to prevent oxidation, pressurizing to transfer the wine, or purging hoses, pumps, bottling lines, and other equipment to remove air and moisture. With an on-site generator, the winery can dial in the purity level—from 95% to 99.999%—depending on what it needs for any step in the winemaking process.

On-site generation also removes the risk of missed deliveries, supply chain disruptions, and gas scarcity in some parts of the country, which leads to gas company allocation limits. This approach shifts the cost structure from variable to fixed, eliminating the risks inherent in delivery contracts, such as price escalation clauses triggered by unforeseen circumstances such as HAZMAT, fuel, or tire surcharges. There is also a hidden cost of nitrogen lost when "empties" are returned to the gas company with nitrogen left in them. Additionally, 3% of nitrogen gas "boils off" from tanks into the atmosphere daily.

Reducing Carbon Footprint

"Our mission at Atlas Copco is to help our customers reduce their carbon footprint by providing the most energy-efficient compressed air systems we possibly can," says Thiel. "This is critical because it takes a lot of energy to compress air. If a winery uses 100,000 kilowatts a year at $0.36 per kilowatt hour, that very quickly turns into a big number. These compressors haven't always been cost-effective, but our newer technology is much more efficient."

Generating nitrogen with an in-house air compressor uses less energy than required to compress it off-site and transport it to the winery. A winery should always consider two levels when computing its carbon footprint. One is the winery's direct impact from its internal wine production operations, and the other incorporates indirect impacts, including transporting materials like gas and glass to the middle of the wine country. Nitrogen deliveries are typically on a weekly delivery schedule, which multiplies the transportation costs.

Atlas Copco is a 160-year-old global air and gas equipment manufacturer that began making nitrogen generators when customers began encountering delivery delays and sought an alternative solution that would allow them to make nitrogen themselves. It offers a breadth of nitrogen generators in both PSA and membrane technologies. 

"What separates us from the competition," says Thiel, "is that we provide the entire package, from the air compressor to the tanks to the filtration to the nitrogen generator. Many of our machines are smaller in size than those of the competition, as well. As a one-stop shop, we also offer a solution to determine a winery's CO2 emissions footprint and help guide it in reducing its carbon footprint."