Time to Take a Stand in the Cork Versus Screwcap Debate

Posted on July 30, 2012 by Nick

What’s your stand on cork versus screwcap? Personally I am in favour of cork. There are arguments on both sides concerning taste, contamination, ageability and environmental issues. Harpers reported last week that in a surprising u-turn Rusden Wines have abandoned screwcap for cork after five years of “persistent quality control issues” using screwcaps. The Barossa Valley winery will now bottle its entire product range under cork.

Rusden winemaker Christian Canute told the Australia’s Wine Business Magazine:

“Our wines are handmade and bottled without fining or filtration. Under a screwcap I have noticed the wines ‘sweat’, producing overly dominant reductive characters, a problem we have never had under cork.”

He added that Australian sommeliers had confirmed the reductive, ‘sweaty’ characters he was experiencing in the winery with the wine under screwcap. Trade customers were also experiencing high incidence of bottle variation.

“From a technical point of view, from a sustainability point of view, from a consumer point of view and from an aspirational, premium factor point of view, cork is the best companion to wine.”

 


Harpers noted that 2 other wineries have returned to cork – the South African winery Klein Constantia (which had been using screw cap) and Napa Valley-based Rutherford Wine Company (which had been using synthetic cork). Their decisions were driven by concerns over reductive characters under screwcap and both environmental and technical benefits.

If you are wondering what ‘reductive characters’ are this refers to the rotten egg like sulphur odours (known as reduction) that can build up in screw capped wines. Sulphides exist naturally in wine and when they degrade they produce a compound called a thiol which is what gives sulphur its smell. Corks allow oxygen into the bottle, which desulphides the thiols and stops them smelling, but screw caps do not allow this. Excess use of sulphur dioxide during bottling can exacerbate the problem.

 

Copper sulphate can be added to the wine to get rid of the smell but this can also cause problems. Traditionally copper sulphate is added to bulk wine at very low levels and is filtered out before bottling. Some industry sources say its use became more common as screw caps increasingly replaced corks. In 2007 high copper levels were found in a 4000 case shipment of New Zealand screwcapped wine that was rejected by a German company as it said that the level of copper in the wine was well over the European recommended limit.

Those who support the use of screwcaps say the risk of smelly wine is better than discovering that your bottle has been ‘corked’. TCA – the chemical compound 2,4,6-trichloroanisole which is found in corked wine – is responsible for ruining the wine. Corks are the preferred closure for premium wines as they help the ageing process. Screwcaps have been the closure of choice for younger wines that are intended to be drunk quickly.

There are trials going on to prove which closure is best – the real acid test of cork versus the screw cap will happen around 2017 as Chateau Margaux have laid down ten cases of Le Pavillon Rouge (their second wine) under screwcap as an experiment to reveal the truth once and for all.

Bordeaux itself has embarked on Europe’s first major trial of a natural cork closure which claims to stop cork taint in wine. In 2007 Chateau La Dauphine in the Fronsac region agreed to bottle 300 wines under ProCork and compare them against 300 stored under natural cork. They will be tasted once a year over 10 years. Gregor Christie, inventor and director of ProCork, says his cork uses a system of extremely fine layered polymer crystalline membranes on each end of the cork. ProCork was founded in Australia in 2002 but uses cork sourced in Portugal. These allow oxygen in, but block the TCA molecule, the cause of cork taint in wines.

Contrary to popular belief and what most publications in the media today “advertise”, TCA is present in less than 1% of bottled wines today according to several recent studies. The cork industry itself has woken up in the last few years and implemented processes that have lead to decreasing levels of tainted corks. However, few in the media are talking about this improvement. So, it is common to hear that 1 in every 10 bottles is tainted by TCA, but in reality it is less than 1 in 100 and decreasing.

 What are your opinions on the cork versus screw cap debate?

Origin information: bordeaux-undiscovered.co.uk