The Loops: The Industrial Lifecycle of Cork

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This is the third and final piece in a series exploring cork from designer and educator Daniel Michalik. As a prelude to this series, Michalik produced a beautiful photo gallery documenting the cork harvest.

I am sometimes asked about a rumored “cork shortage” which has fueled the popularity of synthetic bottle closures such as plastic stoppers and screw caps. There is a 20-acre paved lot in the Portuguese city of Coruche, 100 km NE of Lisbon that answers the question in a rather awe-inspiring way.

Standing along the elevated perimeter of the site, one looks across a vast landscape of cork bark, piled high in mountain after mountain. Some of the hills glow with the intense orange of freshly harvested bark. Others have been sitting outside, uncovered for a year, their color turned a slate gray.

It is in this lot that a portion of the yearly cork harvest awaits the sorting, boiling and trimming necessary for it to be made into billions of stoppers for wine bottles. The facility is one of several in the area belonging to Amorim & Irmaos, the world’s largest producer of cork stoppers and related products.

cork_1grades.pngQuality control classifications at Amorim. The left column indicates thickness, the right indicates quality.

As the leading manufacturer of cork products, Amorim’s industrial facilities exemplify the many layers of re-use and value-adding that typifies the industry. Touring their factories throughout Portugal I found an industrial system comprised of closed, interlocking loops, where a sustainably sourced raw material becomes a product (wine stoppers) then is repeatedly transformed into new objects of value. Moreover, what remains after these loops have run their course is still not considered waste, but biomass: a source of energy to power the factories that keep the loops in motion.

Prior to the mid-1990’s the natural cork industry controlled 95% of market share for wine bottle closures. With the advent of synthetic closures the market dominance was cut by nearly one third in less than a decade. This trend is rapidly turning around however. In 2010 preference for French wine producers was 87% for natural cork closures and in Italy it was 90%. Bottle closures are still by far the most profitable use for the cork. However, the market shake-up has led to significant investment in alternative uses for cork and in the environmental optimization of the industry.

cork_2stacks.pngLeft: a stack of cork awaiting sorting. Right: hand-cutting to size.

Broadly, the cork industry is predicated on the concept of repeated value-addition into what would otherwise be waste. There are numerous profitable applications for the material after stoppers are made, such as flooring, wall covering, insulation and home accessories. This diversity of application has led to factories that are built around using material as efficiently as possible.

Most wine corks are made by hand. Sections of bark roughly 5x5x40 cm are conveyed to a technician that operates a power-assisted punch, punching out stoppers one at a time. The process is rhythmic and highly skilled. Speed is key, but equally so is accuracy and material quality. Watching the cork-maker is like watching a percussionist, simultaneously operating the punch with his foot while moving the material along with his hands and using his eyes to find the best sections of material. While robotic sorting machines and stopper punches are humming away nearby to produce lower-quality corks (and higher reject ratios), it is still profitable to engage trained eyes and hands to read the bark and choose where to strike.

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VIDEO 1: Hand-punching bottle stoppers from bark. The physical process involves a foot operation of a power-assisted punch, along with quick and skilled hand-eye coordination to select which sections of bark will produce the best quality and yield. Depending on quality, a stopper ranges in price from a few cents to a few euros per piece, so it pays to have a skilled puncher. VIDEO 2: A robot feeding sections of bark to the robotic punch. VIDEO 3: A robotic stopper punch. This machine does not read or select for quality. Therefore the level of “waste” is quite high, as a high percentage of the stoppers produced will have air cavities. These are sent directly for grinding and re-use.

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