Tuesday, February 6, 2018

All about cork! A tour of Novacortica Cork Factory!

We're currently travelling Portugal as we're planning to move here shortly. And Portugal as some of you know, has 50% of the worlds cork production, some 100,000 tons of cork is produced each year here!  Yesterday me and Erik visited Novacortica Cork Factory in S. Brás de Alportel and it was a truly enlightening experience! Read on if you wish to know learn more about cork and cork fabric!


Happy me learning about cork fabric production!

Novacortica means new cork and the factory with 60 employees principal activity is the manufacturing of natural cork discs that go to champagne cork stoppers and 1+1 stoppers.

Gowing Cork
When a cork tree first is planted, the tree has to reach 25 years before the first layer of bark can be stripped. The production of cork is heavily regulated by the government, and the tree also have to be at least 24 in (60 cm) in circumference. This first layer stripped after 25 years is called "virgem" or virgin, and is useless for the wine industry and fabric production. After 9 years the tree can be stripped again, and this second layer is also useless for quality wine production and fabric making! Only after the third stripping, so after 43 years can the cork produced by the trees be used for quality wine corks and cork fabric! So if you plan on planting some cork trees, know that it's your grandchildren that will be profiting from that investment. Luckily they live for 300+ years, so it's at least a really long term investment ;)

The stripping of the cork is done by manual labor, by highly skilled workers whom with a specialized axe strips the cork tree of its bark during the summer months. This is when the bark naturally separates from the trunk and can be harvested without harming the tree. If the worker isn't skilled, the underlying layer of cambium (which is responsible for the regrowth of the cork bark) can be harmed and the tree can be damaged, or potentially die from infections or fungus.

Raw Cork "planks" outside the factory.

Cork Production
When the raw cork planks arrive at the factory, they're carefully sorted by hand by very skilled men (it's a tough job, requiring quite a bit of strength to cut clean the edges of the planks to determine quality), whom determine the initial quality of the cork, and the cork is sorted. The thicker the cork bark is, the lower the quality is, as it gets more porous with thickness. In the photo below you can see the clean cut sides towards us, and the raw sides to the left.

The pile to the right have all been sorted as they're the same thickness. Only the piece in the middle of the three she's holding, will be used for champagne corks and quality cork fabric production, the the other, thicker ones are too porous. 

In the photo above, the bottom piece she's holding a thick piece which will be sold off to another factory that make whole piece wine corks for medium quality wines, that will be stored for about 5-8 years. The vast majority of the cork production is aimed towards the wine industry (and I'm a wine enthusiast as well as a fabric enthusiast ;) ), hence a little wine information too. Since this cork is rather porous, if used as is for wine corks, the wine would get too much air, and possibly even run straight out through the holes! So the corks once cut out, will be rolled in a fine cork dust mixed with natural, tasteless glue to create a barrier for the wine and air.

The left is the cork cut out raw (and has quite a few holes as you can see), the right cork has been rolled in the cork dust and "sealed" and is ready to be used.

Once the finest, densest cork has been selected, the planks are packed in big piles and lowered into 100°C boiling water for an hour, to kill any bacteria and possible pests in the cork, as well as make it soft and pliable. It's then pressed to make the planks flat for production.

Boiled, pressed and ready for production!


These are two totally different qualities of cork planks, both boiled and pressed and ready for production.

The planks are then separated to three sections, the bottom layer, middle layer and top layer, in that order in the photo below. Only light coloured middle layer is used for champagne corks and fabric production.

Left to right, bottom, middle and top layer. You can see the different colors.

The top and bottom is torn up and made into granules, which then is used to make everything from low quality wine corks (of course!) cork soles for shoes, coasters, floors, insulation (for space shuttles even!), and a bunch of other uses. The leftovers from the champagne cork and fabric production is also made into high quality, light granules.

Left to right: Top, middle and bottom layer granules in different sizes for different applications.

The three different layers have different colors and VERY different density! The top layer being the densest, least pliable and darkest, the bottom second densest and darkest, while the middle one is lightest in color, weight and is very pliable and squeezable. Those fantastically light and easily worn cork soled shoes you have, are made from the bottom and middle layer granules, those cheap and inexplicably heavy cork soled shoes, are made from the top layer.

Separating and sorting the three layers of the cork planks on the factory floor.

I won't go any deeper into the production of wine corks and champagne corks here, as I'm guessing you're reading for the FABRIC!! ;D

Cork Fabric Production
The middle layer planks of the cork are then glued together into big blocks, and from these blocks thin, thin slices of cork, 0.2-0.3mm (0.00789 inches) thick are sliced. These super thin slices are then glued to a fabric of ones choice to create different cork fabrics for different application.

It's difficult to show how extremely thin this layer of cork is! Like one ply toilet paper maybe?

Different uses for the fabric will get different fabric backings, and the top cork layer get different treatments. All to be able to make them withstand cleaning and the different applications they're meant for. There's cork fabric for uses for everything from upholstery to umbrellas!

Cork fabric chair in the lobby of the factory, isn't is gorgeous!? 

Depending on which side of the blocks one is slicing off the fabric pieces, the pattern of the fabric and the utility strength will be different. The chair and the little pieces I hold in the two photos above are the highest quality fabrics, and also the most durable. If you cut the blocks from "the side", you will end up with this cork fabric pattern which most of you also will recognize. It's however due to it's less dense structure with many more holes, less durable. However, it's very beautiful!

Cork fabric cut on the other direction, here you can maybe get a better idea of how thin it is before being glued to the fabric?

There's also cork fabrics which utilizes scrap pieces of cork (the left and right ones in the photo below) which gives irregular, beautiful patterns, however, the utility strength is really nowhere near as good as the other versions, and should therefore not be used for high stress applications.

Beautiful cork fabrics! 

The metallic flecked cork is glued on a thin layer of metallic fabric before being glued on it's backing fabric, causing the holes in the cork fabric to glitter beautifully!

A couple of the beautiful cork fabric bags for sale at the factory. I bought a yard of the beautiful, blue cork fabric in the lower bag <3


I naturally had to buy some beautiful cork fabric! A full meter (1.09 yards) of this beautiful, purse making grade, treated cork fabric was $40! <3

Me outside the fabric with my shopping.

I can hear you asking, why on earth did she buy so little?! Since we will be moving here soon, I will soon be able to buy much more, without having to fly it all back and forth ;)

Hope you've enjoyed this "virtual cork tour", if you did, please let me know in the comments. And if you have any questions, please ask them below and I'll try to answer to the best of my ability. Make sure you're not a "no-reply comment blogger" by adding a public email to your blogger account before asking questions =)

6 comments:

  1. Intressant material. Har köpt ett par bitar på nätet som ligger och väntar på att bli sydda. Spännande med flytt till Portugal. Ha det så bra!

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    1. Tack! Visst är det fascinerande med kork! Vi ser så fram emot att flytta hit, underbart land! =)

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  2. I have been very curious about cork fabric production so thank you for this blog post!

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    1. Thank you for your kind words! Happy to share!

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