Wednesday, October 10, 2012

Wine is like Oxygen

This one for Live out Loud - theme of the edition was oxygen.

“Love is like oxygen, you get too much you get too high, not enough and you're gonna die. Love gets you high” (lyrics by the band Sweet, ironically their last big hit).

So too with wine.  Oxygen is wine’s best frenemy – vital in the right doses at the right time, but too much and you’re gonna die, and it starts from the moment the grapes are crushed and continues in your glass and then in your blood stream.

With modern wine drinking habits most wines do not need mouth-to-mouth resuscitation but all are destined for a smack on the lips. Taking off the capsule and easing out the cork is not enough foreplay - nor does it allow the wine to breathe.

For wine to take a deep breath it has to be decanted. Generally, the older the wine the more it will benefit from decanting but premium wines under screw cap, for example, can benefit from decanting at any age. 
Mature wines, particularly reds, need some air to revitalise some of their flavours and aromas, even mouth feel, but some are too fragile for decanting. Pour about 50 ml into a glass and re-cork the bottle. Assess the wine immediately, give the remaining wine in the glass a good swirl and then assess it again about 10 minutes later.

If you think the wine has gained more intensity or complexity – the change can be huge - decant the remaining wine and allow it to stand for about 30 minutes. It’s probably a good idea to do this trial with all older whites and all premium wines under screw cap.

If you are in a hurry, wine pourers like Vinturi aerate wine so you can compare straight samples with aerated ones immediately.

The notion that corks breathe is one of the biggest consumer misconceptions in wine. If they did breathe, they wouldn’t be used to seal wine bottles. However, unlike most screw caps, they do allow for nominal gas exchange to enhance wine development. The most popular theory is that air passes between the cork and bottle neck, rather than through the cork as suberin is believed to be gas impermeable. 

This has seen some winemakers – who moved to screw cap to avoid possible cork taint - migrate back to cork. Screw cap producers have countered with liners that allow nominal air exchange, and so the closure battle continues.

Depending on the style and variety of wine at hand, winemakers will either expose freshly crushed grapes to oxygen or protect grape must from oxygen using sulphur dioxide and inert gases like carbon dioxide and nitrogen, known as oxidative or reductive wine making - generally it’s the later, particularly with white wine.

Essentially, protecting the wine from oxygen provides primary fruit flavours and aromas while oxidation – where not taken too far – tertiary flavours, colours and aromas. The earlier the wine (i.e. at juice) is exposed the oxygen the more robust it is to the hazards. Wines are often aerated after fermentation as well as they can become reduced, basically the opposite of oxidation.
Wine is considered a ‘living’ liquid because of the ongoing chemical reactions which can occur very rapidly or very slowly depending on a number of things including how much oxygen is available. The micro-oxidation that occurs in wooden barrels is beneficial in a number of ways not least rounding tannins in red wines and giving whites more tertiary aromas. 

Another good time to use oxygen is when re-hydrating yeast for fermentation. Yeast given plenty of air at this stage develop stronger cell walls which aids resistance to alcohol toward the end of fermentation and reduces the risk of a stuck fermentation - and broken hearts.

Bottling wine is one of the most brutal things you can do to wine. To prevent possible harm and ease the wine out of bottle shock, better wine makers will test for the level of dissolved oxygen in a wine at bottling. If they are below the legal maximum permitted for sulphur dioxide (SO2), they can add more SO2 or sparge the wine with inert gasses or fill the bottles with inert gas just before displacing it with wine.

Wine is like oxygen, you get too much, and you gonna get high.

 Jonathan Snashall

1 comment:

  1. “Bottling wine is one of the most brutal things you can do to a wine.” – That was an interesting opinion. But I do agree that wine bottling is a serious work. At this phase, wine makers have to make sure that the wine is properly sealed inside the bottle, with less to no oxygen inside the container. Improper bottling would lead to spoilage.