Most corks used in closure of wines are made from the bark of the cork oak tree. For a cork tree’s bark to be harvested and used for cork production, the tree needs to be between 25 to 30 years old. The bark of an oak tree that is below 25 years is considered non-viable for harvesting. If you are an environmental enthusiast, there is no need for alarm because the oak tree is not cut down. About half of the bark of the tree is removed to make the cork instead of chopping the entire tree down. As you can imagine, the process of removing bark from a tree without affecting its growth is a labor-intensive procedure that requires skills and special tools. The entire process of harvesting and making the corks is one of the reasons why corks are costlier compared to other bottle closures.
Effect of wine corks on aging
Although wine corks have their imperfections, they are still the more preferable option in the sustainability of wine as compared to other synthetic closures. Wine corks are also a better alternative since they are compostable and will not pollute the environment once you dispose then. This is unlike synthetic closures that may have a negative impact on the environment.
Different kinds of corks affect wine aging differently because of their material. Here is a breakdown of types of corks and their effects:
Natural corks (100 percent)
These types of corks are entirely natural and devoid of plastic or synthetic material. Natural corks come in different grades based on water content, surface, visual inspection, and porosity. If you intend to age wine for more than 5 years, then you may want to consider using corks that are 100 percent natural because their flexible nature makes them seal the wine completely and for a long time.
Colmated corks are simply natural corks whose pores come sealed using cork dust and glue. These types of corks have smooth textures that allow them to slide easily off the bottle when you pull them out. Colmated corks are good for aging wine for about 5 years.
Multi piece corks
These are basically two or more large pieces of corks that are glued together. Multi piece corks are denser as compared to single piece corks such as natural and colmated corks. Cork manufacturers use up the scraps left from the production of single piece corks and combine them to form multi piece corks. These corks are favorable for giant bottles of wine that have wider openings that single piece corks cannot fit. After all, corks are harvested from barks, implying that they have a size limit. The large cork pieces, however, are not recommended for aging wine over long periods.
These corks are made from cork dust and glue. They are cheaper and denser as compared to colmated corks. Note, however, that agglomerated corks are not the best for sealing wine. If you intend to age wine for more than 1 year, therefore, then you need to avoid these corks.