Plat 12

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.

FOCUS ON THE CLOSURE

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!

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.

WHAT THE HECK IS TCA?

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

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!).

At least you know your jacket can breath

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.

SCREWCAP AND REDUCTION

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!

SO WHERE DOES THIS LEAVE US?

Too little

oxygen

contact

Too

much

oxygen

contact

Reductive Balanced

Under the Influence of the Closure

Oxidative

Screwcaps

• Can lead to reductive

flavours.

• Keeps white wines

fresh.

Plastic / synthetic

• Wine oxidizes too

quickly.

• Well suited to early

drinking wines.

Cork

• The perfect closure.

• Well, at least 19 out of

20 are!

• TCA is a problem.

PLATINUM 6