Amorim claim the carbon saved with a cork offsets the carbon cost of the glass
Cork producer Amorim claim that the net carbon absorbed in the production of a cork is 300-500g, while the estimated carbon released in the production of a glass bottle is estimated to be 400g. The claim of absorbing 300-500g is significantly lower than the 1g cost used in a report by Viña De Martino “The truth about CO2 emissions in the wine industry” which said that a cork produced 1g of CO2 in production while synthetic corks and screw caps produced 3g.
The study, commissioned by Corticeira Amorim, but independently conducted by Ernst & Young during December 2019, has revealed that a single natural cork stopper (around 5g) is proven to capture up to 309g which is sixty times its weight in carbon, while the larger sparkling wines were 562g.
Such a large carbon reduction makes the carbon lost due to faulty corks insignificant. The Viña De Martino report estimated the carbon cost of a bottle of wine in its entire lifetime as 1.5kg. Assuming a 2% fault rate from corks the average carbon lost to cork taint is 30g per bottle.