Plat 12
FOCUS ON THE CLOSURE Wine closures are at the centre of a heated debate focusing on which product does the job better. In the left corner, the current world champion, cork! A flexible, perfectly suited option with many years of experience doing the job, but with a fatal weakness, TCA (creating a corked wine). In the right hand corner we have a myriad of other products; screwcap, composite corks, synthetic and glass. At the moment it is a David versus Goliath situation. Out of 18 billion bottles sealed, 14 billion are sealed in cork. But gains are being made by the new kids on the block and we are going to have a look at just what makes a good closure for our favourite tipple.
CORKY! Wine has been closed by cork for over 300 years. It is an absolutely ideal tool for the job. Cork trees are one of few trees that can have their bark stripped and still survive. So, if you want a cork urgently and need to start from scratch, the first step is to plant a cork tree. The second step is to wait 43 years. Once can then harvest the bark to make cork, only having to wait another 9 years to your next batch, all the way to when the tree turns 170 years old. What makes cork so special? It has a honeycomb structure making it very strong but also very • pliable. The cork is made up of gazillions of small gas filled compartments • making it light and easy to compress. It is very resistant to moisture. • It has a major weakness though… TCA! •
WHAT THE HECK IS TCA?
TCA is what causes a wine to be corked. A wine is corked when you taste musty, damp, wet cardboard type flavours. It is very distinct! Technically TCA is known as 2,4,6 trichloroanisole. Chemistry buffs like to keep us in a state of confusion but quite simply TCA is caused by little microbes in the cork reacting with Chlorine, going ballistic and causing a fungi to impart musty flavours. These little microbes often reside in the darker imperfections in the cork, where there is more oxygen and a better chemistry kit for things to happen! TCA is an intense beasty. Humans can pick up 1 part per trillion of TCA in a wine. That is like freezing one second in a 6400 year time period. We are really sensitive to it because evolution has taught us that fungi type flavours might be dangerous. TCA is not dangerous, just a bit funky! So, because about 5% (a contested figure) of wines have TCA in them there is a good case for other types of wine closures.
OXIDATION VERSUS REDUCTION Before we get into the knitty gritty of cork versus screwcap we need to understand the different between oxidation and reduction in a wine. The reason being is we need to answer the question, does a wine need a small amount of oxygen contact to age well? Oxidation Louis Pasteur once said, “Oxygen is the enemy of wine!�. The French tend to exaggerate and in certain stages of wine making oxygen is welcome. However too much oxygen contact will lead to a wine that smells flat, of fresh cut apples where the fruit aromas turn to caramel and the flavour becomes dull and event bitter. The colour of an oxidised wine turns to brown.
People often refer to an oxidised wine as being madeirised, showing traits of the Port wines of Madeira. To protect a wine from becoming oxidised during wine making and after it is opened wine makers add SO2 to the pot. This acts as an antioxidant but also helps kill off At least you know your jacket can breath microbes, which can lead to funky things happening in a wine. White wines typically need higher levels of SO2 then reds to protect them. Red wines have more phenolics compounds and tannin in them which gives the wine a natural defence against oxygen. Interestingly, wines that have been completely protected from oxygen in the production process tend to be more sensitive to its effects afterwards. Good wine making usually involves some oxygen contact, such as when the wine is in barrels, there is contact here, and when the wine is moved from one container to another. The advent of modern wine making techniques has led to a more reductive way of doing things... Reduction Reductive wine making basically involves shielding the wine from oxygen as much as possible. This leads to the more fruit driven wines, and especially crisp white wines. Reduction in wine has been called the new cork taint. I am almost certain this term was coined by a top level marketing executive at a cork manufacturer! Reduction is a hot topic exactly because it places doubt on whether screwcaps are indeed the perfect closure. Reduction in wine is exactly the opposite of oxidation, it occurs from a lack of contact with oxygen. Too much reduction in a wine leads to burnt match, rubbery and sulphur type aromas. It is a fine line though, because reductive aromas include cats pee in Sauvignon Blanc and biscuit in Champagne, both positive traits (for Champagne at least!).
SCREWCAP AND REDUCTION
In addition to drinking beer Australians enjoy conducting wine studies and in ongoing trials of screwcap wines they have consistently picked up reductive aromas in tested wines. This takes place due to the low oxygen environment created, as most screwcaps don’t let any oxygen into the wine. The key it seems to producing screwcap wines that are not reductive in aroma is to limit the amount of S02 used. It is the sulphur in the wine that reacts in a low oxygen environment causing the burnt match aromas.
WHAT ABOUT PLASTIC CORKS? What about them indeed! Apart from being quite difficult to extricate from a bottle, plastic, or synthetic corks, have certainly helped the marketing folk phase out cork in markets that are averse to screwcap. The problem with this closure type is that is hasn’t come close to replicating the incredible traits of cork. They are not as pliable and even worse than that they let in too much oxygen, making it difficult to prevent oxidation for wines that need to be aged. Of course, they are not often used in wines that need to be aged, so this is not a bad compromise by wine makers wanting to preserve the tradition of the corkscrew, take out the risk of taint and purvey early drinking vino.
SO WHERE DOES THIS LEAVE US? Under the Influence of the Closure Too little oxygen contact
Too Balanced
Reductive
Oxidative
much oxygen contact
Screwcaps
Cork
Plastic / synthetic
• Can lead to reductive flavours.
• The perfect closure.
• Wine oxidizes too quickly.
• Keeps white wines fresh.
• Well, at least 19 out of 20 are! • TCA is a problem.
• Well suited to early drinking wines.
The answer to this complex question of which closure to use is constantly evolving as new technologies are found. Screwcaps were hailed as the perfect solution but now reduction is seen as a fault caused by the lack of oxygen in a screwcapped wine. They are beautifully suited to keeping early drinking white wines fresh however and more and more red wines are being placed under this closure, giving us a chance to see how these evolve over time. Synthetic corks just let through too much oxygen and most wines under this closure start to show oxidised characteristics after five years. It is a superb “training wheel” version of the natural cork though. For the traditionalists out there cork is the only answer. Indeed, until a famous Chateau starts using screwcap it will probably stay like this. There is a certain art and ceremony in opening a bottle of wine with a corkscrew. The only problem is if we stuck to tradition we would be commuting to work on horseback! Cork taint or TCA is a huge problem and one that is being faced. New innovations are out there and will be covered in our video tasting on www.undertheinfluence.co.za. The great thing about this debate, is the choice is ultimately yours!
PLATINUM 6