James on different wine closure alternatives

James explains the alternative options for wine closure, including cork, diam, vino lock and screwcap.

Cork vs Screwcap debate continued

The cork, screwcap and diam debate

The passion and spirit of the late Dr John Middleton continues to walk the paths of the Yarra Valley. Mount Mary’s recent newsletter has some interesting things to say about screwcaps, against a background of a move from one-piece natural cork to Diam. I have no quarrel about the choice of Diam, although I question the belief of the Mount Mary team that the overriding problem of one-piece natural cork is or was TCA, when in fact the major problem is random oxidation due to the inherent variability of each and every cork’s oxygen barrier capacity.

What is intriguing is the assertion that one should ‘consider the copper that is added to wines under screwcap to keep the sulphides at bay’. No competent winemaker would add copper in such an amount and at such a point of time that any copper or copper sulphate would remain in the wine. We certainly don’t do that at Coldstream Hills, and I am pretty certain there are very few who do.

The carbon footprint issue also arises. Anyone who has been to Portugal to see the cork production process knows that considerable amounts of energy are used at various stages of the harvesting and treatment of cork, before it is then transported around the world. Diam involves an extra level. It may be light, but it has a considerable volume, and this is part of the shipping cost calculation. Screwcaps are made in Australia with minimal transport/carbon footprint consequences. This, I readily acknowledge, will have passionate advocates on either side of the debate. Also, I am unaware of aluminium toxicity causing proven health problems in Australia. It’s certainly not asbestos.