Screwcaps emit four times the CO2 emissions of cork, says study

Screwcaps create over four times more greenhouse gases than cork, according to the world’s first carbon-footprint study into the impact of wine closures on the environment.

The study, by French agency Cairn Environment, compared a natural cork stopper dressed with a PVC capsule, a Diam closure (a treated cork designed to eradicate incidences of cork taint), also dressed with a PVC capsule, and a screwcap made with 35 per cent recycled aluminium. It found that cork emits 2,490kg of CO2 per tonne, the Diam closure 4,253kg and the screwcap 10,633kg.

The research, which was commissioned by Diam and screwcap producer Oeneo Bouchage, has been ratified by the French Environmental Agency.

However, the study doesn’t take into account the emissions factor as a result of wines that are shipped with corks that are tainted. Estimates for corked wine vary, but it is generally accepted to be around five per cent.