Why Screw Caps?

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Why Screw Caps

The bottom line is that we care about our wines. We work so hard in the vineyard and in the cellar to produce great wines, and it is heartbreaking to see these efforts ruined by cork taint or bad seals. We are committed to delivering great wines to each of our customers, and in order to do that, we need to use the best technology available to seal our bottles. Without a doubt, screw caps provide the best possible seal.

Screw cap closures have been protecting premium beverages for over 30 years. Unfortunately, a certain stigma has developed around screw caps, which stems from their common usage on bad wines in big jugs. This association is really a relic of the past. Screw caps are no longer the tell-tale sign for a bad wine – in fact, the opposite is now true: screw caps are indicators for quality.

The fact is that screw caps are rapidly becoming the closure technology of choice in many countries, for all types of wines, including the most premium ones. Wine consumers in many countries are now playing a real role in the change to screw caps.  Demand from informed consumers for better sealed wines is forcing many producers to look to screw caps for their premium wines.

New Zealand is great example of just how fast the adoption of screw caps is proceeding. The latest wine bottle usage figures show that, since their introduction in May 2001, screw caps now account for 90% of New Zealand wines, including most of their premium wines.  Other countries are also adopting rapidly. The next time you are in a wine store, take a look around at the number of premium wines under screw cap. You will be surprised at how many you will see. Even more surprising will be how rapidly the number of screw capped wines grows.


The benefits of screw cap wine seals are many. First and foremost, the materials used in screw caps are perfectly neutral from an organoleptic point of view. They impart no flavours to the wine, and are completely inert. Corks, of course, impart all sorts of flavours to wines, most of them bad. One of the better known cork issues is “cork taint”, the result of contamination of the wine by trichloroanisole (TCA), a chemical created by the interaction of cork mould and chemicals used in cork sterilisation. TCA-affected wines are characterized by dampened fruit, musty odors, and very unpleasant flavors. Industry research indicates that as many as 10% of cork-sealed wines, or more than 1 bottle in every case, are affected to some degree by cork taint.

The other main advantage of screw caps is their ability to provide a completely impermeable seal to the bottle. When properly applied, a screw cap will prohibit the diffusion of oxygen into the sealed bottle, thus completely protecting the wine from oxidation and spoilage. Neither corks nor their synthetic replacements can do this with any reliability.

Other benefits are less scientific, but no less important. With screw capped wines, consumers can have total confidence that their purchased wine will be in premium condition - alive, abounding with flavours and a pleasure to drink. They can also feel comfortable that there will be less bottle variation, as screw caps provide for much more uniformity in ageing and cellaring wines. And perhaps most importantly, screw caps are very user friendly – no corkscrews to manipulate, no crumbly corks to extract, and if you don't finish your wine that night, you can happily reseal the bottle for the next day.

The Myth of Breathing

Inevitably, the question comes up: aren't screw caps better-suited to early drinking wines only? The answer is a resounding NO. Without a doubt, early drinking wines bottled under screw cap benefit from freshness and elimination of cork taint. However, cellar-worthy wines enjoy the added advantage of dramatically reduced oxidation, and thus, bottle variation and spoilage, which might otherwise result from premature oxidation over the years due to imperfect seals of corks and synthetics.

The next question, of course, is: will screw cap seals allow wine to age? The answer is a resounding YES. The myth that wines need to “breathe” through the cork has been disproved numerous times. In fact, scientific research has shown that the ageing of wine in a bottle is a function of the natural chemical characters in the wine and will occur over time irrespective of the bottle closure. Most of the development takes place anaerobically, i.e. without oxygen, and thus requiring little in the way of “breathing”. Furthermore, there is enough oxygen naturally present in the wine and the headspace between the cap and the wine to allow that part of development which requires oxygen to take place. Proof of this is found in bottles of old port whose corks are dipped in sealing wax that presumably prevents the wine from breathing, and in the bottles that are occasionally rescued from the ocean floor, and taste remarkable despite many years of ageing without “breathing”.