Cork or Screwcap?

Cork or Screwcap?
If you regularly buy wine you will have noticed that more often you are coming across wines closed with other than the traditional cork. Cork is the bark of a species of Mediterranean oak tree which can be stripped without harm from the living tree every ten years or so for generations. Cork has been used as a closure for wine bottles for more than 400 years. But it has one major fault, and a wine with that fault bears its name – the wine is ‘corked’.

If around 5% of all soft-drinks, or canned soups, or any other product were unusable because of faulty packaging it is unlikely their producer would remain in business. But wine-lovers expect, and have been expected, to bear the disappointment of spoiled bottles. Cork had no viable competition until recently when the cork industry began to be shaken out of centuries-old complacency by alternatives such as glass, plastic and screw-cap closures.

A closure is required, as a minimum to do two tasks. To provide a seal that stops the wine inside from getting out and to prevent anything from outside getting in to spoil the wine. Ideally the closure should not affect the wine and it should be easy to open when the wine is to be drunk.

Here is a quick overview of the strength and weaknesses of each closure:






Fairly good seal


Tried and tested


Can let in oxygen

Affected by TCA = corked

Affects wine with taste of cork

Needs special tool to remove

There are different qualities of cork available depending on what wineries will pay. Expect cheap wines to have cheap corks


Excellent seal

Easy to open, no tool needed

Tried and tested

Good seal can cause ‘reduction’

Easy to reseal bottle

The market leader
is Stelvin brand

Plastic closure

Wineries can
use same machinery
as used for corks

Seal doesn’t last

Can affect wine with plastic taste

Difficult to remove

Difficult to replace in bottle

There are several
of plastic closures


Fairly good seal

Tried and tested


Can let in oxygen

Needs special tool to remove

Guaranteed 'corked' free

DIAM is a manufactured ‘cork’
made from powdered cork
and guaranteed to be free
of the chemical that

‘corked’ wines

Vinlock glass stopper

Looks good
Easy to open, no tool needed

Seal is plastic ring

Untried over decades


Tamper evident

Easy to open, no tool needed

Makes ‘pop’ when opened

Untried over decades

If you want to start an argument among wine lovers bring up the subject of wine closures. Battle lines have been drawn! George M Taber, who wrote the book that the movie Bottle Shock is based on, told me that he’d never come across any subject that was so contentious.

George M Taber went on to research and write a most readable book that tells the story of wine closures and the current situation and if you want to know about the battle to close wine bottles then I thoroughly recommend it. Taber’s conclusion is that no closure is perfect and that they each have their strengths and weaknesses.

Peter F May is the author of Marilyn Merlot and the Naked Grape: Odd Wines from Around the World which features more than 100 wine labels and the stories behind them, and PINOTAGE: Behind the Legends of South Africa’s Own Wine which tells the story behind the Pinotage wine and grape.

Too Cork or Not to Cork
Even the most jaded wine lover will enjoy and learn from this well written, easy reading yarn about that essential but disposable closure that must be removed before we can enjoy our favourite drink. If you’re thinking of a present for a wine-lover, this book will not disappoint.

The Judgement of Paris
This book is non-fiction, unlike the movie Bottle Shock that it inspired, and its more for the dedicated wine fan rather than the general reader. It tells the story of the 1976 tasting of top French and California wines and has a detailed look at each of the California wineries involved. Taber was the only journalist present at the tasting.

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Content copyright © 2023 by Peter F May. All rights reserved.
This content was written by Peter F May. If you wish to use this content in any manner, you need written permission. Contact Peter F May for details.