I learn so much from Karen at Winespeed. Here are two very interesting facts.
Can you believe it costs $90 to pick a ton of wine grapes in the San Joaquin Valley?
Minimum cost is $90 to hand harvest one ton of wine grapes in the Central Valley of California. According to a recent study conducted by the University of California at Davis, 5 to 6 agricultural workers are needed to pick one ton of grapes an hour in that large flat agricultural region. The average total cost for picking a 7-ton vineyard would be between $560 to $700 per acre. In contrast, machine harvesting would cost between $275 to $350 per acre. The cost of harvesting elsewhere in California is much higher than in the Central Valley.
Sixteen is the average number of times a cork tree can be harvested in its lifetime. Corks are made from the thick, spongy bark of the cork oak, Quercus suber, and live to be 150 to 200 years old. By law, trees must be 25 years old before they can be harvested the first time. After this initial quarter century, cork bark can only be harvested every 9 to 12 years. Most of the corks in the world come from Portugal. In all seven cork producing countries it is illegal to cut down a living cork tree.
Having driven through the “cork” regions of Portugal, it is indeed a rather strange site to see the “naked” cork trees. And it is difficult to believe that we have a cork shortage. Perhaps plastic and screwcaps are just the winery’s effort to reduce cost?? But it is strange to drive through southern Portugal and pass by all of the naked trees.
From Cycling Centuries:
Cork Oak is native to southwest Europe and northwest Africa where it is well suited to this climate: An abundant and evenly distributed rainfall, short summer dry periods tempered by atmospheric humidity, very mild winters, clear skies and plenty of sunshine, very permeable, moist and deep siliceous soils.
A fascinating and important tree, Cork Oaks can support diverse ecosystems and for this reason are a protected species, with their harvesting process being heavily legislated and regulated in Portugal. The species, which covers approximately 8 percent of the total area of Portugal and constitutes 28 percent of its forests , grows best in the central and southern parts of the country where the largest stands supplying the greatest percentage of high-grade cork are to be found.
Every year from Mid May to Mid August , well-trained seasonal harvesters stage their harvest of the Cork Oak in Portugal. Once a tree is about 25 years old it can be harvested for its ‘virgin cork’ and then every 9 years after the cork ‘bark’ is harvested, and the year is marked on the tree with the last number of that year (ie. A tree harvested this summer will be painted with a 9). Portuguese law prohibits stripping the trees more than once every nine years in order to protect the species. 38 year old bark (roughly the third harvest) is when the bark becomes of high enough quality to produce wine stoppers.
The harvest of the height of the tree is determined by the diameter, if the tree is 1 metre in diameter, you can harvest three metres of the height of the tree. A Cork Oak lives for about 150 – 200 years on average meaning that it will be harvested about 15 times over its lifecycle.
So, when your significant other or best friends tell you to “stick a cork in it”, you know exactly where the cork comes from!!!