Corks were the first wine bottle seals to be invented and, still today, the majority of wine bottles are sealed with a cork. As a result, a lot of people believe that corks are the best possible closure for wine.
Science, however, boldly defies tradition. Researcher after researcher in the field of wine closures praises the qualitative seal of the modern screw cap. Read on to learn more about why a screw cap can be better than a cork for some wines.
What Is a Cork?
Corks are 100% natural products that are created from the bark of the cork tree, which is also known as the “quercus suber.” The producers collect the bark every few years and cut it into circular pieces. This process doesn’t harm the tree, so cork trees often live for hundreds of years!
Corks’ elastic properties help to perfectly seal wine bottles for several years. However, since they are completely natural products, no two corks are the same. This irregularity between corks can cause issues with the sealed bottles, which we will discuss further down.
The History of the Cork
Cork trees are naturally grown in Mediterranean climates, notably Portugal, Spain, Sardinia, and northern African countries like Morocco and Algeria. In the 17th century, with the invention of the corkscrew, corks became the most widespread types of bottle closures because they were much cheaper than the alternative closure of the time: glass stoppers.
Since then, more and more cork trees have been planted, although Portugal has remained the leader in cork production for many years. Depending on where the cork was grown, the quality can vary dramatically. Cork trees grown in rainy areas are particularly known for producing faulty corks.
Corks: Pros and Cons
The Oxygen Influence
The main advantage of corks is that they allow oxygen to pass through and into the wine via tiny holes in the natural cork structure. Wines that are meant to age for a long time will generally be sealed under a cork because many need this oxygen to develop properly, but there are some notable exceptions. Oxygen intake can also prevent reduction or over-oxidation of the wine, which can introduce aromas of cabbage and rotten egg.
However, oxygen permeability is also the biggest enemy of the cork. Since it is a completely natural product, it has a lot of irregularities. Cork producers can only judge approximately how much air will enter a bottle based on its position on the tree. With this method, they group them into different categories.
Even slight changes in how oxygen is introduced to a bottle of wine will lead to marked differences between bottles of the same batch. These differences can be observed in as little as a few months after bottling, with some bottles seeming less fruity and more tired than others. There are a few very severe cases of cork irregularities, where the wine actually spills outside of the bottle through the cork!
The Cork Taint
Another big issue with corks is the infamous “cork taint.” Cork taint affects between 1% and 3% of all corks, although that number was much higher just 20 years ago. When we say a wine is “corked” it means all of the fruity aromas have been lost and instead it smells stale, like wet cardboard or an old cabinet.
Cork taint occurs when there are certain molecules inside the cork that infuse with the wine. These molecules, although naturally occurring in the cork structure, are more present in corks grown in humid areas that are cultivated with pesticides. There are some companies that control each cork individually, guaranteeing there will be no cork taint, but the price is more than double the standard price for a cork.
Cork taint is one of the most accepted reasons to return an opened bottle of wine. The shop or restaurant you buy it from will take it back and replace it with a new one of the same brand. Depending on store policy, you might even get your money back!
Use of Corks in Sparkling Wines
Corks are one of the two closures that can be used to seal sparkling wines (the other is the crown cap). Their elastic nature creates a very tight seal and, while oxygen can enter through the cork, the carbon dioxide that originally produced the wine’s bubbles will remain in the bottle.
That being said, corks are not strong enough to stay on the bottle themselves due to the high internal pressure. So, metal guards are brought in as a backup and placed around the cork to keep it in place.
The Rise of Screw Caps
A few decades ago inventors at La Boucherie Mechanique made what would eventually become one of the world’s favorite creative methods for closing wine: A fancy-looking metal thingamajig called “The Screw Cap.” They found when they tested their invention on wine bottles from all over Europe there was no taste difference between wines sealed using corks.
In the 1990s, Australian and New Zealand wine producers decided to ride the screw cap momentum, started in France decades ago, and do something to innovate in the hopes of guaranteeing convenience and freshness for the consumer in the wake of an increased need for cork across the globe. The solution was screw caps. Producers used them to seal their wines, from the cheapest to the most expensive. In response to the roaring success of this movement, regions in far-off countries began to follow suit, realizing as they did that screw caps can preserve wines much better than corks can.
What Is a Screw Cap?
Screw caps are metal capsules that seal the wine in the bottle by way of a specific lining. The lining will typically consist of a tin layer overlayed by a polymer, preventing the wine from leaking and oxygen from entering the bottle. The lining is what provides the seal and oxygen protection, while the metal capsule provides the necessary mechanical support.
Screw caps are increasingly popular among producers in many countries since they ensure the wine reaches the consumer exactly as the winemaker intended it to. Austria, Australia, New Zealand, Chile, Argentina, and the US are all choosing to bottle more wines with screw caps year after year.
Screw Caps: Pros and Cons
Screw caps are the biggest competitor of cork in the wine industry. One of their leading advantages over corks and cork alternatives is their ease of use since no corkscrew is required. Just twist and enjoy!
Furthermore, since they are industrially made, each and every bottle receives the same closure quality; no cork taint and no uncontrolled oxygen intake whatsoever! What’s more, it’s very easy to store a half-empty bottle of wine in your fridge for a few days when it’s sealed with a screw cap.
Sparkling wine, however, packs a punch that screw caps are not able to safely seal. So, corks are still used exclusively for sparkling wines. But, this just means we get the classic *pop* when enjoying bubbly!
Can Wines With a Screw Cap Age?
All high-quality white, rosé and red wines with a screw cap can absolutely age! Since they allow less oxygen to enter the wine, they can typically age for longer than some cork-sealed wines can.
Why Did We Choose to Seal Our Bottles with a Screw Cap?
We selected screw cap closures for all of our non-sparkling wines because we had you in mind. Corks, while traditional and often romanticised, can be unpredictable and faulty. We at Dough Wines want to make sure that every bottle of ours that passes through your hands is consistently high-quality, easy to operate, and convenient for storage, so… screw caps it was!