Cork or Screwcap? The Real Science Behind Wine Seals

Is cork still king, or has the screwcap sealed the deal for modern winemakers?

We explore when each closure was invented, why different wineries prefer one over the other, and how they influence wine flavour, ageing, and preservation. Discover the science behind both closures and what today’s trends reveal about wine preferences worldwide.

Choosing the right wine closure might seem like a minor detail, but it can have a major impact on the wine itself, from how it matures, to how long it lasts, and even how it's perceived by consumers. Whether you’re picking up a bottle of McLaren Vale Shiraz or gifting a crisp McLaren Vale Sauvignon Blanc, understanding the difference between cork and screwcap can give you a deeper appreciation for the wine inside. 

So let’s break it down, from the invention of each seal to what’s most popular today, and why winemakers choose one over the other.

A Brief History of Wine Closures

Cork has been used to seal wine for centuries, tracing as far back as Ancient Greece and Egypt. But it wasn’t until the 17th century in Europe that corks became widely adopted, thanks to the invention of the glass wine bottle. Natural cork, harvested from the bark of cork oak trees (primarily in Portugal and Spain), became the standard in wine closures due to its compressibility, elasticity, and ability to form an airtight seal.

Screwcaps, by comparison, are a relatively modern invention. The first iterations emerged in the 1950s, but it wasn't until the late 1970s that Australian and New Zealand wineries began experimenting with them more seriously. Winemakers were looking for a closure that would reduce the risk of cork taint (caused by the compound TCA) and provide more consistency from bottle to bottle.

While cork carries the charm of tradition, the screwcap brought with it precision and reliability. The rise of screwcaps reflected both technological advancement and a changing attitude towards wine storage, particularly in New World wine regions.

Why Wineries Choose Cork or Screwcap

The decision between cork and screwcap isn’t made lightly. For winemakers, it’s about balancing tradition, technical performance, and consumer perception. In Old World regions such as France, Italy, and Spain, cork still dominates. Many producers feel that cork enhances the prestige and heritage of their wines. Consumers in those markets often associate cork with quality and age-worthiness, which further reinforces its use.

In contrast, countries like Australia and New Zealand have embraced screwcaps with open arms. Here, the screwcap symbolises freshness, technical excellence, and a no-nonsense approach to winemaking. It's also cheaper, easier to store upright, and more convenient for the everyday wine drinker.

From a production standpoint, cork can be inconsistent and subject to flaws like cork taint. Screwcaps offer a much tighter tolerance, making them attractive to producers seeking quality control. However, not all wines benefit from an oxygen-free environment, especially those intended to mature gracefully over time. In those cases, cork may still be preferred.

Ultimately, the choice is shaped by winemaker philosophy, export market preferences, and the intended drinking window of the wine itself.

The Science Behind the Seal

The primary function of a wine closure is to manage the wine’s exposure to oxygen. Cork is a natural material that allows a small, controlled amount of oxygen to seep into the bottle over time. This process, called micro-oxygenation, can benefit certain red wines, encouraging complex development and softening of tannins as they age.

However, the variability in natural cork means that not all bottles age equally, some may evolve beautifully, while others may become oxidised or develop “off” flavours. There’s also the risk of TCA contamination, which affects an estimated 1–5% of cork-sealed wines and can ruin the entire sensory profile.

Screwcaps, made from aluminium with a polyethylene liner, create a nearly airtight seal. This can be ideal for white wines and aromatic varietals like Riesling and Sauvignon Blanc, which are typically consumed young and fresh. Screwcaps preserve acidity, fruit purity, and prevent oxidation.

There’s also an ongoing evolution in screwcap technology. Different liners can now be chosen to control oxygen transmission, allowing winemakers to fine-tune the ageing process even with metal closures. As a result, the science of wine preservation continues to advance on both fronts.

Cork vs Screwcap: Which Is More Popular?

In the global wine market, preference is split. Cork remains dominant in Europe and among luxury wine brands, often perceived as more “romantic” or ceremonial. The ritual of uncorking a bottle still holds emotional weight for many wine lovers. Collectors, too, tend to favour cork for wines they plan to cellar long-term.

However, in Australia, New Zealand, and increasingly in the US and South America, screwcap use has skyrocketed. Studies show that over 90% of wines produced in Australia are now sealed with a screwcap. McLaren Vale wineries, known for their progressive approach, are no exception.

Why the shift? It comes down to reliability and consumer habits. Casual drinkers appreciate the convenience, no need for a corkscrew, no risk of crumbling corks, and consistent quality. Younger audiences are also less bound by tradition and more open to innovation.

Interestingly, blind tastings have shown that even trained sommeliers struggle to distinguish between cork- and screwcap-sealed wines, especially in the short term. This suggests that perceptions are often shaped more by tradition than by taste.

How Closures Affect Wine Over Time

Corks are prized for their ability to let a wine "breathe" over the years, which can lead to deeper complexity in age-worthy reds and select whites. Wines sealed with cork may soften and evolve more gracefully over a decade or two. However, this comes with risk, oxygen exposure is hard to control, and even good corks degrade over time.

Screwcaps, by contrast, drastically slow oxygen exposure, making them ideal for wines meant to be drunk within a few years. They preserve bright fruit notes, crisp acidity, and varietal character. For this reason, screwcaps are often used for aromatic whites and fresh rosés.

That said, many modern red wines are also sealed with screwcaps, and age just fine. In fact, winemakers now choose screwcap liners with different oxygen transfer rates to allow slow ageing when desired. This has challenged the myth that screwcaps are only for "cheap" or short-term wines.

Ultimately, the closure influences how wine ages, but doesn’t necessarily determine its quality. A well-made wine can shine under either seal, provided it's matched to the right closure for its style and purpose.

Cork & Screwcap in McLaren Vale Wines

McLaren Vale, known for its bold Shiraz, elegant Grenache, and expressive Mediterranean varietals, offers a fascinating blend of tradition and innovation. Here, you’ll find wines sealed with both cork and screwcap, each chosen intentionally by the winemaker.

Many producers in McLaren Vale have embraced screwcaps, especially for their white wines and fruit-forward reds designed for early drinking. The reliability and freshness they offer make them a natural fit for wines that showcase vibrant regional character.

However, you’ll also find premium bottles, particularly structured reds and reserve releases, sealed under cork. These wines are crafted with ageing in mind, and cork provides a time-honoured path to maturity for collectors and connoisseurs.

At McLaren Vale Cellars, we offer a curated selection of both. Whether you’re buying a vibrant young white under screwcap or a luxurious McLaren Vale Merlot sealed under cork, you’re tasting a wine shaped by thoughtful closure choice and winemaker intent.

Conclusion: Is One Closure Better Than the Other?

So, cork or screwcap?

The truth is, there’s no one-size-fits-all answer. Cork lends tradition, age potential, and storytelling. Screwcaps offer precision, consistency, and modern convenience. Both have their strengths, and both are widely used in quality winemaking across the world, including here in McLaren Vale.

What matters most is how the closure complements the wine's purpose. Next time you twist or pull open a bottle, take a moment to consider what’s gone into that choice. Better yet, taste the difference yourself by exploring our range of beautifully crafted wines, available under both closures, and always chosen with care.