In mid September I read this statement on a wine forum, "A commercial winemaker in Sonoma ...has been using Neocork
synthetic corks but ran into some serious oxidation trouble
with them in which he had to dump some of his cased Chardonnay due to oxidation. When he contacted his Neocork rep, they informed him that a new study shows that Free SO2 levels quickly deplete with the Neocorks leaving the wine vulnerable
Not wanting to rely on hearsay, I sent the following email to Neocork because I was unable to find any information on their website related to this issue. I asked if they had a technical paper (or other document) that discussed the above referenced "study", or any other material that assessed the time nature of free sulfite depletion when Neocorks are use for wine closures.
They replied on 9/26/08, "If you can reply with your winery name and phone number we can contact you directly to answer any technical questions you may have."
I promptly replied 9/27/08, "Thank you for your reply. While I do not represent a commercial winery, I do provide expert advice to many homebrewers (via forums) that make mead. As you may know, a mead's flavor profile, continues to develop over the course of several years - even decades. Because of this long-term aging, potassium metabisulfite is added providing free sulfites that mitigate oxidation - as is done in wine.
Thus, it would be important to know if the use of Neocork closures resulted in free sulfite depletion, which in turn would diminish the anticipated level of oxidation protection.
Therefore, it would be helpful to understand the manner in which Neocork affects the free-sulfite concentration of a bottled beverage, and if the rate of depletion is affected by the type of beverage, its pH, initial SO2 ppm, or other parameters."
That was the last communication I had with Neocork. It would appear that they did not find it important enough to discuss this concern with a lowly homebrewer. Consequently I no longer use, or recommend, their product.
Now you have as much information as I, so the choice is yours...