Cork vs Screw Cap: The Great Debate

It might surprise some that there are genuine wine lovers who will base their buying decisions on the type of closure of a wine.  In the great ‘Closure Debate’ the preference of natural cork has often been justified by an argument linked to the ability to age the wine.  Many an enthusiast will be resolute in that it is only wine under cork that is suitable for aging.  This argument has led many people to expect that all wine under cork is suited to ageing.  This is unfortunately not always true, and many unsuspecting wine lovers have been horribly let down by their 20-year-old bottle of average Merlot that they have been waiting patiently to enjoy.


Natural Cork stoppers have been the traditional choice for sealing wine bottles for centuries.  Natural corks are generally ‘the’ respected method of closure and it is widely perceived that wines under natural cork are the best quality wines.  This is often reflected in producers bottling their top wines under cork and the rest under screwcap – whether for the benefits of cork or the market perception.


Benefits of Natural Cork Stoppers

  • Breathability: Cork is a natural material that allows for slight oxygen exchange, aiding in wine maturation and development.
  • Aesthetics: Cork has a classic appeal, enhancing the presentation of premium and traditional wines.
  • Tradition: Many wine enthusiasts appreciate the traditional aspect of cork stoppers and associate them with high-quality wines.


Disadvantages of Natural Cork Stoppers

  • Wine Faults: You’ve all heard of the term ‘corked wine’; this is due to TCA contamination ruining the wine. It can occur from other sources, but generally speaking, cork is the culprit.
  • Variability: Corks can vary in quality, even within a single batch, resulting in variation between bottles of the same wine. This is particularly acute the longer the wine ages.
  • Difficulty of Use: A bottle sealed with a cork is challenging to reseal if not finished in one sitting. This isn’t to mention the additional hassle of opening the bottle.
  • Cost: High-quality natural cork stoppers can be expensive, driving up production costs for winemakers which can ultimately be transferred to the consumer.


Over the years many cork alternatives, such as synthetic and composite (you might have seen ‘Diam’ on the side of your cork?) corks, have developed – the aim of both products is to reduce cost and risk of cork taint.  Synthetic corks are made from polyethylene (the same substance your milk cap is made of) and composite cork is made from granules of cork bark that have been treated before being shaped and bound back together.  Both options look very similar to natural cork and seem to have passed the ‘aesthetically pleasing’ test in most wine drinkers’ minds.  However, the rate of oxygen transmission, and therefore wine development, tends to be slower than natural cork.


The screw cap was invented by a French company, La Bouchage Mechanique.   Screw caps have gained popularity as a modern alternative to cork stoppers.  With the quality of some wines under screw cap on the market one would be remiss to write off this method of closure just because it has typically been associated with cheaper wines or lacks the ‘sense of ritual’ that comes with a cork.  It is a misunderstanding that screw caps do not allow for the exchange of oxygen through the closure.  Screw caps do in fact allow for micro-oxygenation but at a much slower rate than cork. The liner on the inside of the screw cap determines the rate of oxygen transmission and there are multiple companies offering different liners that they say provide varied rates of oxygen transmission based on the winemaker’s needs.  Some countries (Australia and New Zealand in particular) are way above the curve in terms of screw cap adoption for premium wine.


Benefits of Screw Caps

  • Consistency: Screw tops provide a consistent seal, virtually eliminating the risk of cork taint or oxidation.
  • Ease of Use: Opening and closing a screw top bottle is simple and convenient, making it a practical choice for everyday wines.
  • Cost-Efficiency: Screw tops are generally more cost-effective than natural cork stoppers, reducing production costs.


Disadvantages of Screw Caps

  • Perceived Quality: Some wine enthusiasts associate screw caps with lower-quality wines, although this perception is changing over time.
  • Limited Oxygen Exchange: Screw tops offer minimal oxygen exchange, which may not be suitable for wines intended for long-term aging.


The average bottle of wine that is sealed with a screw cap is typically one that benefits from the retention of fresh fruity and floral aromas otherwise known as ‘primary aromas’- think Sauvignon Blanc or Pinot Grigio.  Since taste is a heavily subjective matter, if you like your wine pronounced in these characteristics then there is no reason to fear the screw cap, in fact it could be viewed as a valuable clue when making your purchase!


You may find that you are often disappointed by wines sealed with a cork as the rate of oxygenation is faster, resulting in a slow loss of these primary characteristics and the development of oxidative notes- which are not always desirable to many wine drinkers.


Given the perception that wine under screw cap is inexpensive, most people would strongly disagree with the fact that wines under screw cap can age.  However, in 2000, an experiment by winemakers in Australia tested this theory.  A total of 250,000 bottles of wine under screw caps were aged.  In 2006, it was reported that the wines developed character, becoming rounder and more complex with each passing year.  Since screw caps often slow down the aging process, wine can retain fruit longer and show layers of complexity associated with age.  If this were not the case, it is doubtful that many highly respected producers such as Cloudy Bay from New Zealand and Penfolds from Australia would be placing their premium wines under screw cap.


There is no argument that high quality wines that can age spectacularly are often sealed under cork.  However, the most important factor to consider before you dive head first into the ‘Closure Aging’ Debate at the next dinner party, is whether the wine in question was intended to be aged at all.  A typical bottle of Merlot that was made to be released onto market and consumed within a few years is unlikely to stand the test of time regardless of the closure method used. If you’d like to experience the positive age that can come with any wine, the juice in the bottle will need to reflect this potential even if it is sealed with a screw cap.


Ultimately, the decision between cork stoppers and screw tops depends on the winemaker’s goals and the characteristics of the wine they produce.  Modern winemaking practices have embraced both closures, recognising that each has a place in the diverse world of wine.  While it might not be the most romantic way of sealing a wine, and the hardcore enthusiasts will dread the audible snap of a screw cap when their wine is being opened tableside, there is certainly value in this method of closure.


This blog was edited and posted by Digital Squeak.