TCA and Other Questions about the DIAM Closure

“Garanti sans goût de bouchon.” Guaranteed not to be corked. Really?

Jamie Goode, one of the industry’s authorities on the science behind wine closures, seems to think so:

”DIAM is a "technical cork" made by combining small granules of cork with synthetic microspheres to form an in-neck closure that performs very similarly to a high-grade natural cork, but without the inconsistency and taint issues. DIAM avoids the problem of cork taint by incorporating a special washing process using carbon dioxide in its "supercritical" state, when it has properties of both a liquid and a gas.

This state is achieved by a combination of pressure and temperature, and it renders the cork granules, for all intents and purposes, completely free of any musty taint. This is no mean feat, and developing this process required some serious investment in both research and plant development, but the need for such a cleaning process was made clear by the failure of DIAM's predecessor, Altec. Altec was constructed in a similar fashion to DIAM, and it looked to be a very good closure; however, the process of breaking cork down into small granules merely distributed any trichloroanisole (TCA) taint evenly among all the granules, and at such a level that an alarmingly high proportion of wines sealed with Altecs were tainted. DIAM, however, has proven to be taint-free….”
– From Wines & Vines, August 2008

As with twist caps, synthetic corks, VinoLok, and any other wine closure for that matter, the possibility of environmental cork taint – that is, TCA infection stemming from the winery itself, from timber used in construction or from corrugated packing materials – remains. Aside from that, though, I still can’t help but wonder if it’s truly impossible for any TCA to remain after the natural cork used in the DIAM goes through its cleaning process. I can say that my experience thus far seems to support Dr. Goode’s claims, as I’ve yet to have a DIAM-sealed wine that was corked. Have you?

I also can’t help but wonder whether that slogan, “Garanti sans goût de bouchon,” which I was surprised to find on a DIAM drawn from a bottle of the 2008 Languedoc Blanc from Château des Hospitaliers, is a marketing campaign sponsored by the producers of DIAM or an effort on the part of the winery to make its customers feel more accepting of an alternative closure. I’m guessing the former, but it may well be intended to work in the latter respect. Has anyone seen the same slogan on a DIAM used by any other producer?

The producers of DIAM are addressing other primary questions faced by the alternative closure market, such as oxygen exchange/oxidation failure (more on this from Jamie Goode), reduction and suitability for aging, and now offer several composition options designed for various cellaring/drinking windows. The only concern I’ve heard expressed by a winemaker is whether the synthetic cementing agents used in the DIAM may, over time, have a detrimental influence on the flavor/aroma profile of wine in the bottle. I’m convinced I’ve had wines sealed with synthetic plastic stoppers that taste of plastic, so I’m curious about that question as well.

For now, suffice it to say that the DIAM is my favorite and seems to me the most promising of the in-neck, natural cork alternatives. I’ll be interested to see how it performs on the market over the next few years.