"To cork or not to cork..." seems to be one of the many topics floating around tasting rooms lately. Often, the perception is that a corked wine is of higher quality than one with a screw top. Why do some wines feature a REAL cork, and others use plastic? Does it really matter all that much?
Real corks (harvested from a cork tree) come from a renewable resource, as the tree does not die when the bark is stripped to make the corks. The bark is stripped by hand every 9-12 years and the trees can live up to 300 years (CorkReharvest.org). They are biodegradable and environmentally friendly. They also support thousands of families as a main source of income. However, corks can often go bad and leak oxygen into bottles. They can also be somewhat frustrating to remove (ever been with a bottle and no corkscrew?)
An alternative to the natural cork is the synthetic, or plastic cork. Synthetic corks are immune to cork taint and cheap to manufacture (cellaraiders.com) These can be recycled, but according to winetimes.co.za, less than one percent of them ever are. If a plastic cork is not recycled, they can be a much bigger threat to the environment, as they are not biodegradable. Plastic corks are poor choice for wines with a long shelf life, as plastic often loses elasticity over time and will not prevent oxidation. Plus, there is still the trouble of opening the darn thing.
The third option is a screw-top. The argument for screw-tops is that it saves wine from being "tainted". Only about 2% of screw-top wines are tainted (compared to the estimated 5 - 10% of cork wines that encounter this problem). They can provide a better seal than natural and synthetic corks and are becoming increasingly popular with producers. They are easy to open and require no special equipment. However, the screw-top is not recyclable and has been argued to be harmful to the environment for this reason.
In closing (pun intended), it seems that both natural corks and screw tops are viable options for wine. Don't discriminate against the screw-top option, but keep in mind that natural corks support a trade and are a renewable resource. And whichever type of bottle you decide to open that evening...Cheers!