Thinking about building a wine cellar or buying a wine fridge to store your wine? Then you’ll first need to choose the right bottled wines—because the type of bottle and closure is just as important for proper wine storage as the quality of the wine itself. So, which is better for aging and storage: wines sealed with corks or those with screw caps?

Why Are Corks So Important for Wine Storage?

1. The Cork Seals the Fate of the Wine

Most foods are best enjoyed when they’re fresh. However, this rule doesn’t always apply to wine. Many wines need to be aged for a certain period to reach their optimal flavor and character. Winemakers understand this well, which is why they devote great effort to managing the aging process. One crucial part of that process is bottling—specifically, how the wine is sealed and what type of closure is chosen.

2. The Secret of Oxygen and Aging

On one hand, the goal of aging wine is to soften the acids and alcohol, allowing them to blend harmoniously. Aging can reduce acidity to some extent—something particularly important for wines from cooler regions, where grapes naturally have higher acid levels.

On the other hand, aging exposes wine to a complex oxidative process. When wine comes into contact with oxygen, a range of transformations occur; in some cases, oxidation produces wonderfully complex aromas. For example, much of the distinctive bouquet of sherry is a result of oxidation. However, fresh, crisp white wines are generally unsuitable for oxidative aging. It’s also worth noting that not all red wines benefit from long-term aging—many actually lose their structure and flavor over time.

That said, oxidation can help reduce unpleasant off-flavors in the wine’s aftertaste. Wines aged in completely anaerobic (oxygen-free) conditions sometimes develop odors reminiscent of burnt or sulfuric notes, like rotten eggs, whereas controlled oxidation prevents these flaws. Additionally, the oxidative process reacts with anthocyanin molecules—the pigments responsible for red color—helping stabilize the hue of red wines.

The choice of bottle closure directly affects how much oxygen enters the wine, which in turn influences its aging potential and ultimately determines its ideal drinking window.

3. How About Cork-Sealed Bottles?

Glass itself is an extremely airtight material, meaning it’s nearly impossible for oxygen to pass through it into the bottle. However, almost every type of bottle closure allows a small amount of oxygen to enter, and the key factor is the material of the closure. A standard natural cork lets about 1 milligram of oxygen seep into the bottle each year. That may sound negligible, but over 2–3 years, this amount is enough to break down the sulfites in the wine (winemakers typically add a small amount of sulfites to prevent oxidation).

Generally speaking, wine closures fall into three categories: natural cork, agglomerated cork (made from compressed cork granules bound with adhesives, with properties close to natural cork), screw caps, and synthetic corks. Natural cork has been used for over 250 years, replacing oilcloth and wooden stoppers as the preferred sealing material. Wines sealed with natural cork typically have the greatest aging potential. Up until about 20 years ago, natural cork was the only closure used for fine wines.

However, the main downside of cork-sealed bottles is the risk of cork taint—a musty, moldy defect caused by a compound called TCA (trichloroanisole). This is why sommeliers often pour a small sample of wine for you to taste before serving—to ensure the bottle isn’t “corked.” Today, about 1% of wines worldwide are affected by cork taint, leading to spoilage and loss of quality.

4. How Effective Are Those Sleek Synthetic Corks?

Synthetic corks are made from polyethylene, the same material used in milk bottles and plastic tubing. After years of research and development, modern synthetic corks now perform almost as well as natural corks in terms of sealing ability. Unlike natural cork, synthetic versions do not cause cork taint, and they actually allow a slightly higher and more consistent amount of oxygen to enter the bottle.

This stability is one of the key advantages of synthetic corks. It enables winemakers to better predict how their wines will evolve in flavor over time. In fact, producers can even choose corks with specific oxygen transmission rates (OTR) to suit the style of wine they’re making, allowing for more precise control over the aging process and flavor development.

5. Are Screw-Cap Wines Any Good?

A screw cap actually consists of two components: the metal cap itself and a liner inside it. The liner—pressed against the lip of the bottle—is what determines how much oxygen can enter, making it the critical part of the seal.

In the past, screw caps came with only two types of liners and were mainly used for inexpensive jug wines. Today, however, many manufacturers are developing high-quality screw cap systems and promoting them as having excellent oxygen control. That said, the oxygen transmission rate of screw caps can vary slightly depending on the liner type—sometimes allowing more or less oxygen compared with high-grade natural corks.

Nonetheless, modern screw-cap wines are remarkably stable, offering consistent quality and protection against spoilage. Many wineries, especially in Australia and New Zealand, now use screw caps even for premium wines, proving that closure type no longer defines quality. For additional wine storage tips on how to keep your bottles in ideal condition, check out our related guide.

6. Which Type of Closure Is the Best Choice?

Compared with natural corks that have been around for more than two centuries, modern 21st-century technology has made all types of wine closures perform impressively well. For everyday wines—those meant to be enjoyed within a year or two—all of the closures mentioned above work perfectly fine. Choosing synthetic corks or screw caps can even help you avoid the risk of cork taint altogether.

Different closures also shape the experience of opening a bottle. Before enjoying your wine, would you rather simply twist off a screw cap, or savor the ritual of pulling out a cork with a satisfying pop?

However, when it comes to wines designed for long-term aging, the best choice remains the natural cork. Its unique balance of elasticity and micro-oxygenation makes it unmatched for helping fine wines mature gracefully over time.