What is cork and what is cork used for?

Cork is the cork oak (Quercus suber) tree bark. In western Mediterranean, Portugal and Spain is where we find this cork oak tree. During their growth, these trees thicken their trunk, accumulating dead and hollow cells outside the wood: the cork itself. This layer insulates and protects the most sensitive areas of the tree. The cork tree can reach 20 meters in height and can be 300 years old. In this blog I will focus on the cork oak in Spain and Portugal.

Alcornoque cork oak iberian ham Seville

Growth of cork in a cork oak tree in Cadiz, Spain los alcornocales natural park

After reading this you may think that extracting the cork reduces the tree’s defenses, and you are not wrong. However, the bark of the cork oak has an extraordinary property: regeneration. The cork grows back once extracted, without harming the tree. It is true that until the bark starts growing the tree is under threat from diseases, fire hazards and more. Nevertheless, the industry of cork extraction protects these huge managed woodlands throughout western and southern Iberian peninsula from being cut down for new developments or farmland.

Benefits from harvesting cork?

Managed cork oak forest – la dehesa (in Spain) or montados (in Portugal) – is a unique natural ecosystem in the world. Worldwide there are around 2 million hectares of managed cork oak forest. Portugal has 34% of the world surface, followed by Spain (27%), Morocco (18%) and Algeria (11%). The cork oak is the national tree of Portugal and the law has protected this tree species since Medieval times. Portugal is responsible for at least 50% of the global market for cork.

In Spain, the main areas of cork oak are in the mountains of Cadiz, in Extremadura, Huelva, the mountains in Málaga,  Sierra Morena, Montes de Toledo, and in various regions of Gerona.

In Spain, the Natural Park of the Alcornocales in Cadiz stands out. It is the largest and best conserved cork oak forest in Spain and one of the largest in the world.

The production of cork allows the existence of huge expanses of managed forests where animals roam freely. It allows cattle to feed on the undergrowth, acorns, and mushrooms, giving an incredible taste to the meat, such as with Iberian pork (click here), and produce meat in a sustainable and more ethical way.

When giving you the choice of drinking from a cork bottle or a screwtop bottle, you are helping these natural areas to exist. If cork use keeps going down, landowners will try yo find an alternative economical use to these cork oak forests.

Cork oak extraction tour Los Alcornocales natural park Cadiz

The cork oak (Quercus suber) is one of the species that absorbs the most C02 during photosynthesis. For every kg of cork, 50kg of CO2 are absorbed from the atmosphere, essential for fighting against climate change. Once mature, the cork oak is the center of life in the forest: it shelters a wide variety of animals, retains moisture in the soil, and its roots help reduce erosion.

It provides local income through cynegetic uses, cork extraction, charcoal, firewood, grazing, mushroom picking, acorn oil and acorn liquor.

Mediterranean forest Los alcornocales Natural Park hiking tour Cadiz Tarifa Iberian pig in dehesa

Cork throughout history

These managed cork oak forests were first used by the Iberians, native people from the Iberian peninsula, since the Bronze age. They have been used since at least 7000BC (such as near the megalithic enclosure of Almendres), by the Lusitanians and Tartessians, among others These sites testify to one of the greatest social, cultural and economic changes in the history of mankind. the transition from hunter-gatherer to that of pastor-farmer. The idea of domestication and control, not only of animals and plants but of landscapes as well.

There is knowledge about the use of cork as a stopper for the conservation of wine since the Roman Empire. These were great connoisseurs of wine, its secrets and its aphrodisiac and intoxicating effects. They used a piece of cork oak bark wrapped in pitch or resin to cover the amphorae.

Much later, in the 18th century, Dom Pierre Pérignon used the cork to keep his new invention, champagne. In recent times, the textile and construction sectors, and even aerospace industry use cork for its benefits.

Uses and benefits from using cork

Cork is an elastic, impermeable, insulating plant tissue, with natural resistance to fires, hypoallergenic (no or little possibility to cause an allergic reaction), and of course it is resusable and renewable. That is why it has the following uses:

-The most common use is making stoppers for wine however it is not the only use.

-The next most common use is for the construction sector. Cork applied in coatings for thermal and acoustic properties, as well as for insulation and composite agglomerates.

-The rest of the cork extracted is used in the fabric and textile sector. Fabric or plastic is covered by an extremely thin layer of cork, and it is now widely applied in design, clothing, footwear, and luxurious finishes.

-The aerospace industry finds cork very useful as well. Cork is the material of choice for the thermal shields installed inside the spaceships sent into space by various international agencies.

How to extract cork, types of cork, and how to process it

A cork oak can be 300 years old and when well cared for, provide more than 15 harvests throughout their lifetime. The first peeling happens after the tree reaches 25 years of age, and each harvest must have a spacing of 9-12 years from the previous harvest.  It will especially depend on the annual quantity and distribution of rainfall. The first cork extracted with commercial value happens when the tree is 40 years old.

There are three different types of cork: Virgin cork, which is the first peeling and has poor quality; Secondary, which is the second peeling and has medium quality; and finally the Amadia, which is all peelings from the third peeling onwards and is a good quality. The peelings keep improving with time, so the older the tree the better the quality.

secondary cork oak extraction. Almost ready for cork extraction in Cadiz

The harvesting continues to be a manual work by small teams of experienced workers using axes and ladder to pull down the cork. A more experienced person cuts the cork horizontal to the tree at the top and bottom of the cork sheet they want to extract, creating a capital “I” and then they peel the cork. Cork harvest season is around June and July, depending on the weather.

Local people extract cork without damaging the tree, the extraction is an ecological and sustainable activity if it’s done correctly. If they damage the bark, the tree will heal itself but it creates a bump in the cork. This means the next time it is not possible to extract a big sheet but a smaller one due to the imperfection.

Some rural people still use donkeys/mules to adapt to the harsh terrain, and in other more managed lands they used vehicles to carry the extracted cork.

Cork oak extraction tour in Los Alcornocales natural park with mules carrying cork

How is Cork processed

The bark rests stacked in the open air for approximately 6 months. In this way the cork loses moisture and its composition becomes more homogeneous. Then the plates go to the cooking process, where the cork boils in boilers for one hour in order to eliminate impurities, improve its elasticity and increase its volume.

Finally, the company will cut the cork, shape it, and brand it if necessary for the final client.


Los Alcornocales Natural park in Cadiz

If you are visiting Cadiz I really recommend visiting Los Alcornocales natural park and doing a hike here. In addition to the opportunity to see the only remaining subtropical forest in mainland Europe (laurisilva) you will see the largest cork oak forest of Spain and one of the largest in the world.

I recommend first visiting the information centre of the Aljibe in the Benalup to Alcala de los Gazules road. Here you will learn everything about this natural park in Cadiz, the mediterranean forest, the traditional uses, cork, and more.

information Los Alcornocales natural park in Cadiz, Spain. Area to learn about mediterranean forest and cork

After, enjoy hiking in the northern part of Los Alcornocales natural park. If you hike from the Sauceda area up to the Aljibe you will be walking through a cork oak forest and a subtropical forest. From the top of the Aljibe peak, the tallest peak in Los Alcornocales natural park of Cadiz, you have one of the best views to see everything, from Gibraltar to Jerez de la Frontera and Cadiz city.

What is TCA or what does it mean if a wine is corked?

Due to its elasticity and impermeability, cork stoppers are good to allow a micro-oxygenation of the wine. Cork is very important for a wine to age well and improve with time. However, it is important to have the bottles at a temperature and humidity controlled space. This will prevent the cork reducing in size and letting wine or air flow.

TCA is a chemical element of natural origin that in certain concentrations are responsible for alterations in the wine. The compound forms through the interaction of plant phenols, chlorine and mould.

This taint can originate in the bark of cork oak or, most commonly, elsewhere in wineries, where damp surfaces and chlorine-based cleaning products are commonplace; barrels, wooden pallets, wood beams and cardboard cases are all sources of phenols. If TCA goes undiscovered, it can spread and eventually taint the wines. New technology eradicates TCA, if discovered.

Private full day tours through Cadiz province and Andalusia

If you are looking for Iberian ham tours or hikes in Los Alcornocales Natural Park in Cadiz, then keep reading. I will now take advantage to show you the great tours throughout Cadiz province and Andalusia that we do. I do tours where we will hike along the largest cork oak forest in Spain, and learn how local people extract cork.

Guided hiking tours in Cadiz province

Cadiz province is one of the most biodiverse provinces in mainland Spain. Habitats range from dense forest reminiscent of cloud forest to Mediterranean forest, dune systems, and more.  In fact, in Cadiz as mentioned above, you will find the largest cork oak forest in Spain. Moreover, you will be seduced with views of magical landscapes in Cadiz and the Strait of Gibraltar. Cadiz has over a third of its surface protected, while its climate and sunlight hours are similar to Canary Islands.

Coastal hiking tours in Cadiz

In our guided nature tours you will learn about the local history, traditions, and the many culinary, medicinal and traditional use of Mediterranean plants found within Cadiz province. You will find many of these plants in your supermarket in lotions, herbal teas, and to flavour your food or even eat them as part of your main plate.

I will lead you in these hiking trails to get the most out of these hiking tours in Cadiz province. Furthermore, I will also explain the habitats that we find and some the landmarks of the hikes. I will help you identify Mediterranean plants and explain the traditional, culinary or medicinal use that it had in the region.

These hikes last from 3.5 – 7h depending on the guided hiking tours in Cadiz that you choose. Most of the hiking tours I offer consist of hikes that last 3.5 – 4.5h (8-13km). However, we can design longer or shorter hiking trails if you prefer a different one.

Hiking tour in los alcornocales natural park

Join this hiking tour near the heart of Los Alcornocales Natural park in Cadiz. In this guided nature tour in Los Alcornocales we will discover more about Cadiz, its nature, gastronomy and traditions.  We will learn about the culinary, medicinal and traditional use of Mediterranean plants, found internationally, while taking in incredible views. In this hike you will also learn about the local fauna, and the socioeconomic benefits that nature provides to the local people. Finally, we will taste an extensive traditional food tasting such as; cheese, game meat, local wine, local rice, and more.

Culinary food tours

We do an Iberian ham tour from Seville and Cadiz. Enjoy a tour visiting the Mediterranean forest and the museum to learn the traditional methods for curing meat products, and then the current curing process of chorizos, loins and Iberian ham. At the end we will have an extensive tasting of a wide variety of cured meats. If you decide to do the full day tour we will head to the local caves where we will be astounded by the beauty and the size of it, a total of 2130 subterranean meters divided in three levels. You will visit 2 levels in a circular route of around 1km.

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Hiking and culinary tours in Cadiz

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