Bottlers of noncarbonated soft drinks, juices, water, wine and beer many times use LN2 injection equipment to insert small measured drops of LN2 into their containers.
Bottlers of noncarbonated soft drinks, juices, water, wine and beer many times use LN2 injection equipment to insert small measured drops of LN2 into their containers. Processors of nuts and other perishable items also often use LN2 to provide an inert atmosphere in containers. Soft food packages are also pressurized by liquid nitrogen injection to protect the package contents from crushing.
When used for inerting, the dosed liquid rapidly evaporates into tasteless, colorless, odorless, inert gaseous nitrogen that displaces the oxygen-laden air in the container. The container is then sealed, resulting in an inert environment. By reducing the oxygen content of the environment, the LN2 dramatically extends the product shelf life.
When used for pressurizing, a small dose of liquid nitrogen typically is introduced into the container after it has been filled with product. The container is immediately capped or sealed, trapping the expanding gaseous nitrogen and creating positive pressure inside. Pressurizing enables processors to use thin packaging materials and yet be able to stack them for distribution.
Liquid nitrogen pressurization is often used in hot filling operations. The pressure introduced as a result of the nitrogen dose compensates for the vacuum conditions created when the hot product cools to ambient temperature. Without a dose of liquid nitrogen, some thin containers made from such materials as HDPE or PET would collapse when the hot contents cool to ambient temperature. Pressurized PET bottles are also less prone to “jamming” on high-speed lines and create a better surface on which to affix labels. The enhanced surface makes it possible to use less costly labeling materials and reduce overall packaging costs.