It’s called the DIAM, and although I’m certain that I have pulled it out of numerous wine bottles, I hadn’t heard it described since a French winemaker told me about it last night. But first, a little background.
By now, alternatives to cork are very much in the mainstream of winemaking. The biggest revolution has been the increasing popularity of screw caps. Randall Grahm, the founder of California’s Bonny Doon Vineyard, has used them for years on all his wines, including his signature red, Le Cigare Volant, and white, Le Cigare Blanc; overall, they have gained broader acceptance for white-wine use than for reds, although many producers in Australia and New Zealand are using them for both.
Alternatively, plastic closures have captured a piece of the market, mainly for inexpensive wines intended for quick drinking. Some still question the ability of the new closures to permit long-term wine aging because they allow less air to enter the bottles. One of the leading reasons the industry has turned to them, of course, is the fact that a small but annoying percentage of natural corks are tainted with TCA (2,4,6-trichloroanisole), a compound that “taints” the wine and infuses it with a musty off-smell that is often described as resembling a damp cellar or wet newspapers or cardboard.
That said, there those who still refuse to part with the cork, including most French winemakers. “I’m against plastic, I’m against screw caps,” Pascal Guilbaud, owner of Guilbaud Frères, a producer of Muscadet in France’s Loire Valley, declared as we sat together at a dinner built around Muscadet last night here in New York (I’ll have more on the wines in a coming post). And then he told me and a colleague, Tyler Colman of Dr. Vino, about the alternative he does use, describing a product that is reconstituted from cork after it is broken apart, heated and purified.
With a little research, I landed on the Web site of the DIAM closure, a so-called “technical cork.” How is it made? At a production facility in Spain, raw cork is cleaned by boiling, then ground into a cork “flour.” These cork granules are then subjected to a process using pressurized carbon dioxide that penetrates and cleans them. The company says this removes 99.8 percent of TCA as well as other harmful compounds that can cause bad aromas. The granules are then re-assembled and baked with a binding
agent “to give each DIAM closure a homogeneous structure and perfect neutrality,” according to the Web site. “This combination allows free expression of the wine's aromas without interfering with its natural development.” In other words, the corks allow the wine to breathe. Dozens of wineries are using DIAM closures in the U.S., France, Australia, New Zealand and South Africa.
Back at our dinner, Pascal Guilbaud said he now swears by the newfangled corks and hasn’t seen one bottle of his Muscadet tainted by TCA since he started using them. No, he has no use for plastic or screw caps at this point. But with the DIAM closure, aided by a little technology, he can still say he uses corks in his bottles.