Corks, screwcaps and closures

Natural cork allows a small, variable amount of oxygen through over time, which many believe contributes positively to development. Its historic problem is TCA contamination, which has been substantially reduced but not eliminated.

Screwcaps eliminate cork taint entirely and allow very little oxygen through. That preserves freshness and can, in some wines, encourage reduction — which is a real trade-off, not a defect of the closure.

Technical closures — agglomerated cork, DIAM, synthetic — sit between the two and offer more consistent oxygen transmission than natural cork.

Australia and New Zealand adopted screwcaps close to universally as a deliberate industry decision. It was about eliminating TCA, not about cost.