Corks could slow ageing in wine

Natural corks may release phenolic compounds which can slow the ageing process and increase the health benefits of wine, according to Paulo Lopes, oenologist and member of Amorim’s R&D team.

cork-bark.jpgSpeaking at the Wine Faults Workshop at the London International Wine Fair last week, Lopes said: “Natural corks are rich in phenolic compounds and we are looking at whether they can migrate into the wine.”

According to research conducted at the University of Oporto, cork dust has been found to have both anti-oxidant and anti-cancer properties.

However, Lopes added: “With a whole cork we don’t know if these phenolic compounds are able to migrate and if they contribute in a positive way to the wine.”

Meanwhile Lopes presented research to show that the main source of oxygen in wines sealed with cork was not from the atmosphere but from the cork itself, and that it was released primarily at bottling when the corks are compressed.

This explains, he said, “Why oxygen entry occurs in the first two to three months [for wines closed under cork] and then stabilises.”

He added that testing oxygen transmission rates over a 24 month period on wine bottled under a range of closures showed that synthetic closures gave the highest levels of oxidation and screwcap the greatest levels of reduction, while cork sat somewhere in the middle.

Ronan Sayburn MS, director of wines at Hotel du Vin, was also present and talked through a series of wines with different faults.

Addressing the delegates at the event, he said: “The most common wine fault is oxidisation and you often get it due to heat damage, especially if there is a lot of temperature variation because if there is thermal expansion and contraction of the cork then it works like a piston drawing oxygen into the liquid.”

Patrick Schmitt, 26.05.2011

No Responses to “Corks could slow ageing in wine”

  1. Ken says:

    Until cork can claim reliability it simply has no place in a modern world where the consumer/we demand better than “average” and currently that’s the best performance possible from natural cork. whilst However, Lopes added: “With a whole cork we don’t know if these phenolic compounds are able to migrate and if they contribute in a positive way to the wine.” claiming that cork dust has both anti-oxidant and anti-cancer properties is surely something of a strech?

  2. John Casey says:

    As there is virtually no contact between the wine and the interior of the cork, the only compounds, other than those on the inner surface of the cork, that can move between the cork and the wine must be volatile. This would seem to exclude most phenolic material.

    The diffusion of small bubbles of gas from the cork can be seen by laying the cottle on its side after corking. Passage of atmospheric oxygen through the cork is not possible because of the elevated air pressure in the cork cells.

  3. Broady says:

    These guys will say anything to keep market share they lost due to the neglect of their customers n the new World wine industry. We know exactly what nasty things can happen to a bottle of wine when a bad cork is placed in it. Ok so screwcap isn’t the answer to all problems but they sure go a long way in keeping the inherent quality of the wine in the bottle without the variation of cork.So guys,you can munch into your corkss for your health,I’ll keep using the better screwcaps for my customers wine.

  4. Jonathan Healey says:

    Ken: winemakers tell me cork failure rate is now around 2% – that’s commensurate with failure rates for typical condom use! Screwcaps contribute to reductive sulphur aromas to a much greater degree. Oxygen ingress rates for plastic corks should rule them out as a closure for quality-minded winemakers. Cork is also the most environmentally-friendly closure – very modern world! For more:

  5. Marco Biondi says:

    Awesome Dr. Lopes.. you are saying just the truth

  6. Andrew Morris says:

    While I understand how disappointing it is to open a well aged special bottle of wine only to find that it is corked, it is, IMO, important to keep in mind changes that have come about over the last 10 or so years in the cork industry. Quality producers, like Amorim, have made great strides in quality, reducing taint levels to between .2% and 1.2% depending on the type of cork used.

    People still see higher rates. I believe there are 2 reasons: 1. quality variation from producer to producer; 2. There are still lots of older wines in cellars that were closed with corks produced before the industry improved.

    True enough that cork makers were passive until challenged by other closure types. True enough that the possible benefits of cork phenolics seems like a reach, at least at this point.

    However, corks really are a good option as a closure. We use Amorim Twin Tops on our white wines. We drink a LOT (2+ bottles/day) of our own white wine. We are pretty good tasters who can pick out a tainted sample. One on our team is a competitive tasting champ. It has been over 2 years since we have seen a single tainted bottle of our whites.


    Andrew Morris
    Briceland Vineyards

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