Cork uncorked

Lana here--we have been incredibly curious about the cork trees that we see from the highway. Unfortunately where we are staying in Évora, there doesn't seem to be anything available for tourists to see or learn more about cork production here. I guess this might be like heading to Saskatchewan and hoping to get a tour of a wheat farm or to go to a wheat museum. Nothing really exists like this.

Portugal produces about 50% of all cork production in the world. The bark is removed by hand by extractors who must carefully cut sections of the bark ensuring they do not damage the tree while removing high quality bark for processing. Trees need to be about 25 years old before they can be harvested and the first 1-2 harvests produce lower quality cork. These trees live up to 300 years. The acorns that fall from these trees feed the Prata Negro (black pigs) that are also famous in this area.

First up--here's a real cork tree (Quercus super--the Cork Oak) that has been recently harvested. You'll notice that the freshly exposed internal core of the tree is bright red. There is the number 5 painted on. We saw trees where the bark was beginning to grow back as the red will turn to dark brown, then black as it regrows. We got pretty excited as we were approaching Évora and seeing cork forests from the highway!!

Cork Oak tree

Up close, you can see the interior of the bark that looks like the cork you would see in a wine bottle.

The cork industry is truly self-sustaining/minimal carbon footprint as the bark grows back without harming the tree. Trees must be 30 years old and about 2' in circumference, otherwise, it would be permanently damaged when the bark is removed. The year of the harvest is painted on the tree to ensure that the bark is only removed every 9 years.

Cork bark up close!!

More cork bark up close.

The bark on the tree looks grey, porous and spongey. 

Most of the trees we've seen have a bottom band of bark removed that is about 3-4 feet in height or a similar length removed from the middle of the tree indicating they have only harvested a section the bark from the tree. This one looks like is got completely stripped all in one year--the full Monty!!!

Another cork tree, but most of this tree has been stripped.

Okay, now onto the processing. We pulled these pictures off of the internet to add to this post just so you could see what the production is all about. The bark is washed and soaked in water. This not only cleans all the impurities and dirt from it but also softens the pieces so they can be laid flat which is easier to work with. 

The actual corks are all punched out of the bark by hand.  This is a highly skilled occupation as the technician needs to ensure he produces the highest quality and number of corks from each piece of bark.  

I always wondered if the cork was produced horizontally or vertically from the bark. Turns out it's vertical as you can see from this picture. 

Really thick bark is used to create champagne corks to fit the larger openings on champagne bottles.  Speaking of champagne--one of my most favourite beverages--it turns out that the cork for champagne is cut using the same symmetrical shape as that for wine bottles. So, how does the champagne cork get it's unique "mushroom" shape?  Well, it turns out that the cork is only inserted 2/3rd's of the way into the bottle. So the 1/3 that's left coming out of the top of the bottle naturally expands as the cork absorbs moisture with the 2/3 section expanding only to fit the neck of the bottle. This results in the unique mushroom shape that helps with the manual extraction or uncorking of the champagne bottle--simply twist AND pull at the same time to remove.  

I didn't know this but read that corks can be "mono" as in one solid piece of cork or "agglomerated" where they grind up small pieces, glue them together into long rods and then cut to be made into wine bottle stoppers. Agglomerated corks are not as good in quality as mono corks. Agglomerated corks are also made for champagne bottles.