Cork versus screw cap: the wine holy wars

If you want to start an argument between wine professionals, just mention a preference for cork over screw cap or visa versa. For many consumers in Australia or New Zealand, this may seam like a strange argument when around 90% of all wine sold in Australia is under screw cap (often known by the brand name Stelvin). It may seem logical to use screw caps as they’re easier to open and reseal, whilst better preserving the freshness and aromas of a wine. But it wasn’t always this way.

Before bottles, wine was stored in barrels, and before that, in tall clay containers called amphorae. When bottles were first invented back in the 17th century, something was needed to seal the neck of the bottle to stop the wine from spilling out. Oil-soaked rags were used at first, but the bark of the cork oak tree (Quercus suber) was found to seal the bottle much better, especially for transport. Cork quickly became the preferred enclosure.

Natural cork offers a number of advantages:

• It’s a natural and environmental friendly product;
• It can mould to the neck of the bottle sealing it quite effectively;
• It allows a small amount of oxygen into the wine which aids in the ageing process.

Unfortunately, natural oak also has a number of disadvantages:

• As with any natural product, quality can vary;
• Faults with a cork can allow too much oxygen into the wine, detrimentally affecting the aromas and flavours;
• Corks can disintegrate over time, either impacting the wine quality, or just making the cork very difficult to remove;
• Faulty corks can taint wine by releasing a compound called TCA.

Cork taint is one of the biggest issues with using cork. It can affect up to 7% of wine bottles especially those stored for a long period of time…that is roughly one bottle in every dozen.

I have regularly heard stores of one, or two, bottles out of every dozen old wines being cork tainted. This can occur even if the wine is stored under perfect conditions, and can be heartbreaking, especially if you’ve lovingly stored the wine for a decade or more.

As you can well imagine, the need to find another bottle enclosure was a priority for many years.A number of cork variants were tried with varying levels of success including:

• Amalgamated corks: These are made of cork pieces that have been pulverised and then treated to stop the formation of TCA. The pieces are reformed into a single piece, just like a regular cork, only better. These enclosures have all the benefits of cork with the reduced chance of TCA. One of the best known brands is Diam;
• Synthetic corks: These are corks made out of plastic in the shape of a natural cork. While synthetic corks don’t have any issue with TCA, there is a concern that the plastic might impart a slight chemical flavour into the wine. So they are not recommended for long term storage. They are also not environmentally friendly unless they are recycled.

Enter the screw cap. Interestingly, screw caps have actually been around since the early 1970’s and were pioneered by the Australian Winery Yalumba.      Although it originally met with consumer resistance, the screw cap was reintroduced in the late 1990’s and has been a great success in the Australian and New Zealand markets because:

• It removes any chance of cork taint;
• It allows wine to be stored upright, rather than lying down which is required to keep corks wet;
• It preserves the fruit flavours and freshness of the wine longer;
• It is easy to remove and reseal;
• It allows less oxygen into the wine preserving the wine better and reducing the chance of oxidation.

The last point has proven the most controversial. This is because, if oxygen is part of the long term ageing process of wine and forms part of the wines character, then could limiting the amount of oxygen negatively impact the process? And it is still unknown how screw caps will react to decades of ageing – will they degrade or fall apart?

It’s hard to believe that there is still resistance to bottling wine under screw cap in many parts of the world, with the biggest issue being the perception of quality. For many overseas consumers, they consider wine bottled under screw cap to be ‘cheap’ wine, and that quality wine is only bottled under cork. Although this is slowly changing this is still the perception in China and the USA, two of Australia’s big export markets. For example, Penfolds sells many of their premium wines under screw cap in Australia. But those same wines are bottled under cork specifically for export. In fact, in some regions of Spain and Italy it is actually illegal to bottle wine under screw cap, and this further affects consumer perception.

So the next time you are opening a wine, give a thought to the wine enclosure and how it might have either influenced the wine inside, or affected your perception of the brand or quality. If you would like to find out more, head over to our events page. I am also happy to tailor corporate events to your needs and budget – perhaps a selection of aged wines under cork and screw cap to demonstrate the impact on wine for your clients or team. Feel free to reach out to me here for an initial discussion.

In the meantime, if you need any tips or advice then feel free to reach out to me on our Facebook page and sign up to my mailing list to get access to our newsletter and wine specials.

Cheers,

Antony.