That cork from your wine bottle might come from Cal Poly. Here’s a look at how it’s harvested
Ever seen where corks for wine bottles come from?
Neither had plenty of attendees at a Cal Poly event Tuesday, until a team from Portugal hacked off a slab of cork from a tree at the San Luis Obispo university as part of a rare harvesting event that only happens every decade or so.
The event was hosted by Cork Supply, a leading provider of best-in-class cork closures, according to a company news release. The ceremony brought together students, professors, wine distributors and other experts to see bark be split in the traditional manner of harvesting mature cork oak trees.
Cork oak is only eligible for harvesting about every nine years, so not many have the opportunity to witness the rare sight.
Botany professor and director of Cal Poly’s Plant Conservatory Matt Ritter said the university is home to about 50 cork oak trees, which are unique because they regenerate bark after harvesting. This means the trees remain intact for future harvests.
The gathered cork then is used for closures for wine and other bottled beverages.
Monika Michalski, Cork Supply’s global marketing director, said the company has been building relationships with universities to spread knowledge about the use of cork in the wine industry — and Cal Poly seemed like a great place to do so locally.
“Usually we have to take people to Portugal for them to see the cork harvest,” Michalski said. “This is like right in your backyard.”
Because of its growth cycle, there are specific rules that have to be followed when harvesting cork, Michalski said.
“There should be a certain cadence to it to make sure that the cork comes off easy, that we’re not harming the tree, that the tree is being respected in its growth cycles,” Michalski said.
Ritter said this event is a way to demonstrate to Cal Poly students how this sustainable material is harvested.
“You just don’t get to see it in the United States very often,” he said.
All cork forests are located in Europe and North Africa, with the majority — about one-third — located in Portugal.
Frederico Mayer, Cork Supply’s purchasing director of raw materials, said each tree can produce about 1,500 corks per tree with around 50 trees per hectare — about two-and-a-half football fields — in a typical cork tree forest.
Michalski said the company ends up using about 99% of all raw cork material that they purchase. If they can’t use cork for sealing bottles, like if there are defects in the cork, Cork Supply will use the raw cork for other products or or even energy generation, grinding it down into dust to power factory plants.
In addition to regenerative bark, cork trees also have the ability to sequester carbon emissions, storing the greenhouse gas. The harvesting process forces the trees to regenerate bark, and the trees accelerate their CO2 drawdown after absorbing carbon dioxide in their bark.
“All of the CO2 that we’re putting in the air?” Cork Supply global director of innovation Greg Hirson said during the event. ”It’s like running it backwards by storing in corks.” Some estimates show that corks capture almost 400g of CO2 — equivalent to emissions from producing a glass bottle.
Cork Supply will next travel to UC Davis on Thursday to host another harvest. The last cork harvest at UC Davis took place at least 30 years ago, according to campus representatives.
