Natural cork is made from the bark of the cork oak tree, grown primarily in Portugal and Spain. The bark is harvested every nine years without killing the tree. A good natural cork allows tiny, controlled amounts of oxygen into the bottle over time. This slow, steady oxidation is what allows fine wine to evolve and improve over decades.
The problem with natural cork is a compound called TCA (trichloroanisole), which causes cork taint. A corked wine smells like wet cardboard or a damp basement. It is not dangerous but it ruins the wine completely. Somewhere between 2% and 7% of all natural-corked wine is affected, which is not a small number.
Screwcaps eliminate cork taint entirely. They are hermetically sealed, meaning no oxygen enters the bottle. This makes them excellent for wines meant to be drunk within a few years. The wine stays exactly as it was bottled. No variation between bottles.
The trade-off is ageing. Without oxygen, wines under screwcap develop differently over long periods. Some research suggests they age more slowly. Others note they can develop reductive characters like rubber or struck match. The long-term data is still being collected because screwcaps only became widespread in the early 2000s.
The practical answer: screwcap is generally better for wines you will drink within three to five years. Natural cork is still preferred for wines intended to age beyond that.
There is also a perception issue. Many consumers still associate screwcaps with cheap wine. New Zealand and Australia adopted screwcaps widely and changed that perception over twenty years. It is still a slow shift elsewhere.
Synthetic corks made from plastic or plant-based materials are a third option. They eliminate cork taint but allow variable oxygen ingress, making them less predictable than either natural cork or screwcap.
