Wine myths
A screwcap means it is a cheap wine
“Serious wine has a cork. Screwcaps are for cheap bottles and wine that will not age.”
Screwcaps eliminate cork taint and seal far more consistently. Long-term trials show wine ages well under screwcap, and many of Australia’s and New Zealand’s finest wines use them.
The full answer
Cork taint from TCA affects a small but real percentage of cork-sealed bottles, and screwcaps remove that risk essentially completely. That alone is a substantial argument.
Consistency is the other. Natural cork is a variable biological product, and bottle-to-bottle variation in oxygen ingress within a single case is a documented and long-standing problem. Screwcap liners are manufactured to a specification.
The ageing objection has been tested. Long-running comparative trials, notably by the AWRI, have followed the same wine under different closures for decades, and screwcapped wine ages perfectly well — differently, more slowly and more reductively in some cases, but not worse.
Adoption settles the status question. New Zealand and Australia use screwcaps for the overwhelming majority of production including their most expensive wines, and some highly regarded producers elsewhere have followed.
Cork is not thereby the wrong choice. It remains a renewable material supporting a valuable cork-oak landscape, and many producers prefer its oxygen behaviour. The point is that the closure is a technical decision, not a price signal.
A relationship that has been measured across real samples — a correlation between growing-season temperature and harvest sugar, say — without a single demonstrated mechanism covering the whole path from cause to effect.
What would settle it: A larger or better-controlled study finding no association.
Sources
Sources consulted
- Longitudinal studies comparing wine closures — Peer-reviewed oenological literature
- Wine flavours, faults and taints — The Australian Wine Research Institute
- New Zealand Winegrowers annual report — New Zealand Winegrowers