On a recent trip to Spain we explored the Sierra de Grazalema National Park and the Los Alcornocales Nature Park in Andalucia. Grazalema is a UNESCO Biosphere Reserve of 53,411 hectares of rugged limestone mountains, while Los Alcornocales is 167,767 Ha of spectacular sandstone peaks and gorges, with a unique flora and fauna, and seemingly endless forests of cork oak. Despite being in southern Spain, it is wet, very wet, and water has played a large part in shaping the landscape.
The cork oak forests, some of the most extensive in the world, are a valuable resource both for the local farmers who harvest the bark and the wildlife which live amongst them. The production of the Iberian pig, adapted to a pastoral setting where the land is particularly rich in natural resources, is deeply rooted to this Mediterranean ecosystem and contributes decisively to its preservation. The forests are an important resting place for overwintering birds migrating from the north and the home to a large range of raptors, including Eagles, Vultures, Buzzards and Kites. The forests also shelter the critically rare Iberian Lynx and other shy mammals.
A mixture of planted and natural forest trees, the cork oaks (Quercus suber) are exploited using traditional methods, carefully pealing the bark from mature trees once every decade.
It is a skilful and labour-intensive process involving teams of five men. The sections of bark are transported out of the mountains, often by donkey, and brought to an area to be stacked and dried in the sun before processing and forming into wine corks. Spain sells about 3 billion corks each year, making it the second largest producer after Portugal.
There has been much talk over the years about the problems of cork taint in wine and of the desirability of alternative closures. In the early 1980’s a compound called TCA was identified as the principle cause of tainted wine and corks were widely blamed as the source of this. It has since been discovered that any use of Chlorine as a steriliser risks the creation of this compound, which gives ”off” flavours to wine. After a very slow start, research funded by the cork manufacturers and government agencies has resulted in improved processes, greatly reducing the problem.
Today, over 80% of the 20 billion wine bottle stoppers used each year are natural cork, 12 % are plastic corks, screwcaps are dominant in New Zealand with around 7% of the total, and 1% of closures are glass stoppers. The humble cork is still very popular and manufacturers have come up with a range of corks for different markets.