Nitrogen wine-making is a way of storing the wine to protect it from oxidation. After the wine has left the cask, winemakers flush the inside of the container with nitrogen to remove evaporated wine. This removes any oxygen residue before the next batch is made.
Sometimes, a winemaker will need to transfer wine from one cask to another. Oxygen can easily mix with the exposed wine during this process. To combat this, winemakers flush tubes and vessels with nitrogen to remove oxygen residue before transferring the wine. Additionally, nitrogen can also assist with fermentation and eventually the bottling process. More about winemaking