Archive for the ‘Wine Technicalities’ Category

Whats the difference between a corked wine and an oxidised wine?

Wednesday, May 12th, 2010
This is a question i often get when people come into the shop.  In a fact a not so little old lady came in the other day and we got chatting about the very subject.  Now this lady has been drinking wine a while and while not exactly adventurous in her tastes, she does like to try the odd different bottle from her staple Pascal Bouchard Chablis Vielles Vignes (managed to convince her to try the wonderful Domane Wachau Collection Gruner Veltliner 2008 which she thought was lovely).
Domane Wachau Gruner Veltliner 08

Domane Wachau Gruner Veltliner 08

I’ll set the scene.  She had been in a restaurant recently with some friends for a big birthday with a 6 in it and had ordered a bottle of the Chablis from the list (not Bouchard i hasten to add) which she had drank before and enjoyed, however this time the Chablis didn’t taste exactly as she remembered.  She said the colour was slightly darker than normal and the nose was slightly sweeter and while not completely unpleasant  didn’t taste quite right.  Now she made the right move and asked for the waiter and had wine to be replaced, saying that the wine was corked.  The waiter duly tried the wine and disagreed that the wine was corked but thought it was oxidised, however he replaced the wine with no further argument.  This sparked a debate between the woman and her friends regarding what constituted a corked wine, as this is what most people called a wine that was off. Right?

Pascal Bouchard Chablis Vielles Vignes 06

Pascal Bouchard Chablis Vielles Vignes 06

So to set the record straight then.  A wine that is corked DOES NOT have little bits of the cork floating in it, annoying though it may be.  This has to be the single most annoying thing people get wrong when complaining about wines.  This happens when the corkscrew has been pushed through the bottom of the cork on opening thus causing fragments to fall off into the wine.  Nor does mould on the outside of the cork mean the wine is corked, this can be a simple fact that the wine has been stored in a damp environment where mould can develop.  A corked wine is actually affected by a bacteria called trichloranisole (TCA for short) which affects the corks before they even enter the bottle.  A wine which suffers from this condition smells mouldy, mouldy like sweaty old socks that have been left in a kit bag for a couple of weeks.  Very obvious, very strong and not at all pleasant.  Now not every wine suffering cork taint smells strongly, some may only have a meer indication of it which would have the effect for dumbing the fruit and making a distinctly unmemorable drinking experience.

On the other hand an oxidised wine is quite different.  These are wines that have had too much contact with air (oxygen).  Indeed wines such as Oloroso sherry’s and Tawny ports actively encourage wines to oxidise to create the style.  Howver most of the time its a bad thing.  In white wines the colour will turn darker, reds wines the colour will lighten and in both wines the colour edges towards brown.  In every case the wines will take a nutty smell and slightly acerbic taste which in time will finally convert to acectic acid and vinegar. 

Therefore a wine that is corked smells mouldy and is caused by bacteria, while a wine that is oxidised is caused by air contact and can actually at times be a good thing, but if it goes too far the wine will change colour and take on the smell of vinegar in extreme cases.  

Corked or Oxidised?

Corked or Oxidised?

Both these major faults in wine can be prevented by the choice of closure.  Natural corks are susceptible to both these, while plastic or composite corks are only susceptible to oxidation.  The stelvin (screwcap) help prevent both these faults through supertight seals.  Beware screwcaps are not completely faultless either, but thats for another day.  On the whole they are by far the most superior method of sealing wines and in particular aromatic white wines today.  Reds benefit from the natural breathability of real corks which experts argue help them age and develop better than screwcap sealed wines.     The choice of seal will depend on the winemaker and the perception they want their wines to have.  As i’m sure you’ve noticed the new world winemakers are much more for screw caps than old world prodcuers, but this is beginning to change. 

So there you have it now you know the difference between corked and oxidised wines.  Until next time wine fans….

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