Diam corks: A great step forward

Most of us have experienced a "corked" wine, meaning a wine that smells and tastes like a wet dirty dog, or moldy newspaper. That flaw is caused by TCA: 2,4,6-trichloroanisole, which can be transferred from a flawed cork to the wine. TCA can be faint, or it can be so pronounced that it ruins the wine. Although corks are of course traditional for wine bottle closures, screwcaps have gained in popularity because the incidence of TCA in screw-capped bottles is near-zero. 

But along comes Mr. Diam, who invented a process for eradicating cork taint from natural corks. In the Diam process, "supercritical carbon dioxide is used to leach out all objectionable compounds within the cork, including TCA. Then, a polyurethane is introduced into the cork, which fills some of the pores and reduces the permeability of the cork. Because all these steps couldn't be done to a natural cork, the Diam corks (as are many others) are made from "agglomerated" cork--cork that is made from small pieces of cork that have been fused together via heavy pressure.

I have used Diam corks, and I'm a fan. Small producers cannot afford to purchase screwcap machines, which cost upwards of $25k (!). So I am happy that a "safe" cork alternative exists. I predict that many commercial users of cork closures will switch to Diam corks, once they learn of the benefits. The last thing a winemaker needs is for his or her wine to suffer from TCA taint.

Incidentally, the process of taking cork from special oak trees in Spain and Portugal looks ghastly, but it is renewable--it does not kill the tree. The tree regrows more cork bark, and can be sustainably harvested on a recurring basis. 

Photo is from Decanter magazine, whose excellent article can be found here.