Apologies to those of you who find closures one of the most tedious subjects on the planet. I’m a geek and am proud to admit it. Secondly, not many wine journos want to write about it cos it is too techy so that doesn’t leave much competition when it comes to getting commissions! I also love the fact that there’s always controversy. The different closure companies love to have a go at each other too, making it a bit of a giggle.
The latest research closure reseach has revealed the rate of oxygen transmission (OTR) through a closure can affect the aromas a wine exhibits – and we’re not talking cork taint here, guys.
Studies from the Pontificia Universidad Católica de Chile, The Australian Wine Research Institute, INRA, Geisenheim, and UC Davis suggest that increased exposure to oxygen for some red varieties enhances their red berry characteristics, particularly Grenache, Shiraz and Carmenere.
By selecting closures with the right OTR, it appears to be possible to perform winemaking in the bottle and create wine styles suited to consumer tastes. In Chile, wines sealed with a lower OTR closure such as a screwcap, exhibited more caramel, violet and dried fruit characters while those with a higher OTR closure eg synthetic or natural cork, promoted berry fruits and tobacco.
The AWRI found that Shiraz’s jam, berry and chocolate aromas can be enhanced with very small amounts of oxygen during maturation.
In California, UC Davis report that Chardonnay aged on lees in stainless stell is very responsive to a closure’s OTR: a combination of lees ageing plus lower OTR closure reduced the production of oxidative spoilage compounds thus this information could see producers alter techniques in the winery depending on the closure.
We’re becoming increasingly knowledgeable about the effects of oxygen on the maturation of wine. It’s now clear that a high oxygen transmission rate will lead to premature oxidation while the anaerobic conditions of a tin-liner screwcap is conducive to reduction. However, this latest research is taking things a step further: it seems there will soon be a closure for every varietal and style.
