What Is Cork Made Of?

When you are relaxing on the veranda of a hotel or even a private home. You open a bottle of wine to share with loved ones. You will probably have to pull a cork out of the bottle to actually pour the wine.

Corks are made of a kind of spongy material and have long been used in wine making for sealing a bottle of wine.

What Is Cork Made Of?

However, it is not really explained to those not in the know exactly what cork is made out of. Or why it is so useful when winemaking.

As such, we have decided to write an article today exploring corks. Exactly what they are, and why they are so good at keeping your wine in the best condition.

What Is A Cork?

We will start off for those who have no idea what a cork is, but have heard the term before somewhere. A cork is essentially a bottle cap or top that keeps wine fresh in its glass container.

When you make a bottle of wine, you will put it in a glass container.

This will keep the wine fresh for a long time, as the glass is a neutral PH. This will not affect the PH of the wine itself. It will allow the wine to remain close to the same taste and texture as when it was made.

The problem is you can’t really stopper a wine bottle with more glass. Unless it is fused together, glass will generally be resistant to other glass materials. There will be space in between the glass, which will allow outside exposure to affect the wine.

Cork is spongy and dense, while also being pliable. This means it can be pushed into a wine bottle’s top without resistance.

The material can fill the gaps that would otherwise appear and so stop any outside exposure or material interacting with the wine, thus creating a fantastic stopper.

What Is Cork Made Of?

Considering how strange of a material, cork is, you would think it is made from some fantastic substance that is found in only one place in the world.

While it does tend to only come from one source, it is not limited in terms of its geography.

Cork is made of the inner bark layer of the Cork Oak. A tree that is native to the Mediterranean basin in the areas of southwest Europe and northwest Africa.

The outer layer of the bark protects the tree. It`s the hard shell that we are all keenly aware of when we touch tree bark. Just underneath this is the phellem layer of bark tissue, which we turn into cork.

Cork from this tree is a truly amazing substance that humanity has used for over 5000 years.

Due to the hot, dry Mediterranean environment it is native to, it has developed adaptations that make it incredibly useful for civilizations.

The bark is hydrophobic, which makes cork impermeable to water and buoyant on top of water. This is believed to have evolved in the tree to combat the intense thunderstorms that can rock the region it lives in during certain times of year.

The bark is also very fire retardant and will not catch light easily. Another adaptation towards these storms, which in a dry place can spark forest fires from the lightning they expel.

Finally, cork is fairly elastic and even when it has been pushed or pressed into another shape, it will almost always go back to its original shape afterwards.

As such, cork has been used for many things over the years. The most obvious one is wine stoppers.

Cork’s nature means it interacts very well with the hard substance of glass, and so it is perfect to stopper wine. It has also been used in fishing floats and buoys, as well as acoustic sound and insulation as well.

Is Cork A Good Product For The Planet?

The cork industry is actually considered one of the most sustainable on earth.

Most cork forests exist in Portugal and Spain, with a few in Morocco, Algeria, Tunisia, Italy, and France, however almost 50% of global cork production comes from Portugal.

Cork trees live for up to 300 years, and their bark is not harvested until they are at least 25 years old. Once they reach this age, the bark is stripped from their trunk without the tree being cut down.

Then the tree is left to regrow the bark, and it will not be stripped again for another 9 years.

Since the trees are left to grow in their own time and not cut down for their cork, cork forests create a natural wildlife haven for animals and ecosystems.

Many endangered species rely on these forests for protection, including the Barbary macaque and the Iberian lynx.

Since Cork forests don’t need good soil, a lot of water, and are resistant to fire, they actually prevent desertification and a Cork forest often stops a desert from spreading effectively.

The industry helps to keep these forests maintained and relevant, and their presence helps keep ecosystems and communities safe.

Is A Cork An Indicator Of A Good Wine?

Traditionally, the answer to this would have been yes, they do indeed. This was because the alternative – in screw tops and caps – didn’t let the wine breathe in the same way a cork did.

This meant that once you opened a wine bottle, you would have to let it sit before drinking it. While corks didn’t allow outside substances in, they did let the wine breathe out a little through its limited pours.

However, in the modern day, screw tops and bottle caps are able to let wine breathe. So now they are more or less balanced rather than corks being better.

Yet, since corks are environmentally friendly, we would say that corks are definitely the better option of the two.

Nowadays, if you want to know whether a wine is good, you should try it or trust another’s opinion before drinking. Regardless of corks, screw tops, or caps.


Cork is made of the inner bark of the Cork tree, which is a spongy, elastic, fire resistance, and hydrophobic substance that is perfect for bottling wine with.


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