Everything to know about wine closures

closeup on multiple wine bottle closures, 3d renders by Outshinery
10 min read

Wine closures

Many materials are available for sealing a bottle of wine, each with its own pros and cons. From natural cork to synthetic cork, aluminum composite to plastic, and even wax seals, there are plenty of options to choose from. In this article, we'll explore the various materials used in wine sealing and packaging so you can make an informed decision when selecting the best option for your winery.


Corks have been used to seal wine bottles for centuries, and the type of cork used significantly impacts the wine's taste, price, and aging potential.

[fs-toc-omit]History of corks

The use of cork as a stopper for wine bottles dates back to at least Roman times. Cork is derived from the bark of cork oak trees which grow primarily in Portugal and Spain. The bark is harvested every nine years without damaging or killing the tree. It is then boiled to soften it before being cut into strips that can be punched into discs known as corks.

[fs-toc-omit]Traditional types of corks

Three main types of corks are used in winemaking: natural cork, synthetic cork, and composite cork.

Natural corks are made from 100% natural cork oak tree bark. They are considered superior for their ability to age wines properly over time due to their porous nature, which allows oxygen exchange between the bottle and the atmosphere.

Synthetic corks are made from polyethylene plastic or rubber compounds that mimic natural cork but do not allow oxygen exchange. Hence, they are better suited for cheaper wines that should be drunk within two years of purchase.

Composite corks are a combination of both natural and synthetic materials designed to provide some oxygen exchange while still providing an effective seal against leakage.

3 different examples of corks for wine: natural cork, agglo cork and colmated cork
Natural cork | Agglo cork | Colmated cork

[fs-toc-h3]Innovative corks

In recent years, two new types of corks have entered the market —DIAM and Nomacorc. Both are a departure from traditional cork, offering wineries unique benefits that can help them better protect their wines.

DIAM is a type of cork made from natural cork granules that have been treated with a patented process to make them impermeable to oxygen. The result is a cork that is much more resistant to oxidation than traditional corks, allowing wines to stay fresher for longer periods of time.

Nomacorc is a synthetic cork made from polyethylene foam. It's designed to be completely impermeable to oxygen, making it ideal for long-term storage of wine. Additionally, it's also highly resistant to taint compounds, which can give the wine an unpleasant musty odor or taste if present in high enough concentrations.

closeups of a DIAM cork and a nomacorc
DIAM | Nomacorc

Both DIAM and Nomacorc are much more sustainable than traditional cork due to their low environmental impact during production and manufacturing processes. For example, while natural cork requires harvesting bark from trees every 9-10 years, which can lead to deforestation if not managed properly, neither DIAM nor Nomacorc require any harvesting since they're made from recycled materials or synthetic polymers, respectively. These innovative corks are also typically much less expensive than natural cork ones, down to a quarter of the price, making them extra appealing in an environment where recent inflation is a struggle.

[fs-toc-omit]How the choice of cork affects wine quality

When it comes to choosing a cork, there are a lot of options to consider! Natural corks, composite corks, synthetic corks, technical corks, Diams, and NomaCorcs all have their own advantages and disadvantages. However, it is important to note that corks are only one way to close a wine bottle — screw caps, glass stoppers, and more innovative solutions are also available. Keep on reading to learn more about these other methods of sealing wine bottles.

[fs-toc-h3]Screw caps

One popular alternative to cork is screw caps or Stelvin closures. These metal lids are becoming increasingly popular due to their convenience and affordability. They provide a reliable seal that prevents oxygen from entering the bottle and spoiling the wine. Additionally, they can be easily opened and resealed if needed.

[fs-toc-omit]History of screw caps

Screw caps have been used for centuries to seal food containers and other products. However, it wasn't until the 1950s that they began to be used for sealing wine bottles. The first commercial use was by Australian winemaker Penfolds Wines in 1957, who used Stelvin-type screw caps on their Grange Hermitage wines. Since then, many other wineries around the world have adopted screw cap closures for their wines.

[fs-toc-omit]Types of screwcaps

The Stelvin original is the most common type of screwcap used in the wine industry. It is a simple aluminum cap with a plastic liner that provides an airtight seal.

The Stelvin LUX has a more sophisticated design, featuring a plastic outer shell and an inner lining made from food-grade silicone rubber. This type of cap provides an even tighter seal than the original version and gives the bottle a more luxurious look.

The third type of screwcap is the Stelvin without knurling, which has no knurled edges or ridges on its surface. This type of cap is often used for sparkling wines because it helps maintain carbonation levels better than other caps.

examples of regular stelvin screwcap, LUX stelvin screwcap and no knurling stelvin screwcap for wine bottles
Stelvin original | Stelvin LUX | Stelvin without knurling

[fs-toc-h3]The newest kind of screwcaps: WAK closure

A WAK closure is a type of screw cap used to seal wine bottles. It is made up of an aluminium cap with threads that fit the neck finish of the bottle and a liner made from plastic, cork, or other materials. The WAK closure combines traditional aesthetics with modern technology to provide a perfect seal that prevents any liquid leaking and keeps other flavors out of the wine. This ensures that the quality and taste of the wine remain intact until it is opened.

closeup of a WAK screwcap closure
WAK closure, the next-gen screw cap for wine

[fs-toc-omit]Advantages of screw caps over cork stoppers

The primary advantage of using a screw cap closure is improved quality control and consistency. Unlike corks, which can vary significantly in terms of size and density, screw caps provide a consistent seal that prevents oxidation and spoilage due to cork taint. They are much easier to open than corks and don't require special tools or expertise. This makes them ideal for everyday wines that don't need to be aged for long periods of time.

[fs-toc-omit]How the choice of screw cap affects wine quality

The impact of different types of screw cap closures on wine's taste and aging potential varies depending on several factors such as grape variety, vintage year, region/appellation, etc.

Overall, choosing which type of screwcap to use for your wine bottles depends on how long you plan on storing them before drinking them, as well as your desired level of quality and preservation. By understanding these factors and selecting the appropriate type of cap accordingly, you can ensure that your wine will remain at its best when enjoyed.

[fs-toc-h3]Glass stoppers

Vinolok is a revolutionary glass closure developed by Alcoa, a German company, for use in wine and spirits bottles. It is also known as a “glass cork” and has become an early alternative to traditional cork closures. Vinolok closures are made of a recyclable and reusable material—glass. They come in different types, such as the screw cap, Vino-Seal, Zork, and others.

closeup of a vinolok on wine bottle: a glass stopper
Classic high-top Vinolok, a premium glass stopper for wine and spirits

[fs-toc-omit]Advantages over glass stoppers over cork or screw cap

The key advantages of Vinolok over other glass closures are its oxygen transmission rate, ease of use, reusability, and recyclability. The oxygen transmission rate is much lower than that of natural cork or synthetic corks, which makes it ideal for long-term storage of wines. Vinolok closures are also easy to use as they require no special tools or techniques for opening the bottle. They can be reused multiple times without any loss in quality or performance. Moreover, they are highly recyclable, making them an environmentally friendly option for packaging wine bottles.

Overall, glass wine stoppers offer an attractive way for wine brands to add an extra layer of luxury and sophistication to their products while conveying a premium sense that will appeal to customers looking for something special.

[fs-toc-h3]Wine capsules and naked corks

Wineries have a variety of options when it comes to the type of capsule they choose. The capsule is the protective sleeve that goes over the cork and neck of the bottle. It can be made from tin, poly laminate, or heat-shrink PVC. Tin capsules are the most traditional option and are usually used for high-end wines. They provide a barrier against air and mold growth on the cork and an attractive finish to the bottle. Poly laminate capsules offer a more modern look and come in a variety of colors and textures. Heat-shrink PVC capsules are also available in many colors and textures but do not provide a barrier against air or mold growth on the cork.

In addition to these traditional capsule types, a trend is now emerging: "naked corks." This involves not using a capsule to hide the cork, which often features the brand logo printed on it. This trend offers several benefits, such as being more cost-effective than traditional capsules, creating an eye-catching presentation for customers, and making it more sustainable. However, there are some potential concerns with this trend, such as an increased risk of oxidation due to a lack of protection from air or mold growth on the cork.

Ultimately, wineries need to consider all their options when choosing which type of capsule is best for their wine bottles. They should consider factors such as compatibility with bottle shape and cost vs. quality when making their decision. Whether they stick with traditional capsule types or embrace the "naked cork" trend depends on their individual needs and preferences.

closeup of tin cap on a wine bottle and a naked micro-agglo cork
Classic tin capsule hiding the cork below | Naked cork (can be branded — with a winery logo, for example)

[fs-toc-h3]Specialty wine closures

One of the oldest and most traditional solutions is the dipped wax method. This involves dipping the neck of a bottle in melted wax which seals it shut. The advantage of this method is that it can be done quickly and easily with minimal equipment or cost. However, it does not provide as much protection against oxidation as other methods, meaning that wines sealed with this method may not last as long over time.

zoom on 3 different wax dips for wine bottles
Straight wax for a classic look | Dripping wax for a rustic or antique look | Angled wax for a modern look

Small wax buttons are another popular option for producers looking for an alternative to cork closures. These buttons are placed on top of the cork before sealing the bottle, providing an additional layer of protection against oxidation and preserving the wine’s flavor for longer periods of time. The downside to this method is that it requires more time and effort than other solutions, making it less appealing for some producers who are looking for a quick solution.

closeup on wine bottles closed with an agglo cork with a bit of wax and a button wax
Lightly dipped wax | Wax button at the top of cork

Bartop (t-top) cork stoppers are a type of closure used to seal bottles, typically for wine, liquor and spirits. They are made from natural or colmated cork stoppers with a wooden, plastic or other material capsule applied on top. These stoppers provide a tight seal that keeps the contents of the bottle fresh and prevents leakage. Bartop corks are ideal for short-term storage and consumption of drinks, as they can be easily reclosed after opening.

zoom on a bartop T-stopper for wine and liquor bottles
Plastic bartop (t-top) cork stopper

[fs-toc-h3]Wine closures, in summary

The choice of closure for a bottle of wine is just as important as the bottle shape. Both are essential in preserving the liquid inside, but they also play an important role in brand appeal and customer experience. According to the 2021 Closure Survey Report from Wine Business Monthly, natural corks remain the most popular closure option among wineries; however, it's clear that other options are gaining traction. Ultimately, winemakers must consider bottle shape and closure when crafting their products to create a memorable experience for their customers.

Wine closure suppliers:
  • Amorimcork: Portuguese company that is the world's largest producer of cork stoppers, with a focus on sustainability and innovation. They offer a variety of natural cork closures for wines, spirits, and other beverages.
  • Cork Supply: US-based producer of premium wine corks and closures, specializing in high-quality natural cork products. They offer a wide range of closure options to meet the needs of winemakers around the world.
  • Diam Closures: French manufacturer of synthetic wine closures made from polyethylene terephthalate (PET) material. Their products are designed to provide an oxygen barrier and preserve the quality of wines over time.
  • Etched Images: US-based producer of sealing wax for wine closures. They also specialize in creating unique designs for wineries looking to add a personal touch to their bottles.
  • G3 Enterprises: US-based manufacturer of wine capsules, foil capsules, and shrink sleeves for wineries around the world. They specialize in providing custom solutions for their clients’ packaging needs.
  • Inspiral: UK-based manufacturer of natural cork stoppers for wines and spirits as well as other beverage applications such as beer and cider. Their products are designed to provide an airtight seal while preserving the taste and aroma of the beverage inside.
  • Ramondin: Spanish company that produces natural cork stoppers for wines, spirits, liqueurs, olive oils, vinegars, and other beverages. They specialize in providing high-quality corks that are designed to preserve flavor and aroma over time.
  • Vinolok: Czech Republic-based producer of glass closure systems for wines, spirits, liqueurs, olive oils, vinegars, beers, and other beverages. Their products are designed to provide an airtight seal while preserving flavor and aroma over time without affecting the taste or smell of the beverage inside.
  • Vinvention: French manufacturer of synthetic wine closures made from polyethylene terephthalate (PET) material with patented oxygen scavenging technology that preserves flavor and aroma over time without affecting taste or smell inside the bottle.
  • Verallia is a leading North American supplier of beer and liquor bottles as well as other beverage containers such as cans and jars. They are committed to providing innovative packaging solutions for their customers.
up close and personal on a premium pinot noir label where the embossing and varnish on the label are clearly visible
Laurie MillotteYana

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