- Corks inherently taint wine.
- Corks are singularly to blame for TCA-related taint in wine.
- Corks are outdated; they are "yesterday's" closure solution.
- Synthetic closures and screw caps are fundamentally better closures for wine.
- Synthetic closures and screw caps do not taint wine, because they are TCA-free. - Synthetic closures and screw caps are more consumer-friendly than cork.
- TCA at virtually any detectable level taints wine.
- TCA-related taint in wines is a significant issue for the average wine consumer.
- Cork producers and suppliers cannot effectively control the taint risk associated with TCA.
- Consumers will widely accept wines with non-cork closures.
- Cork producers and suppliers are in denial about cork's flaws and are not delivering effective closure solutions.
- The 1999 AWRI study proves that synthetic closures and screw caps are better for wines than cork.
- Wines with synthetic closures or screw caps are not vulnerable to taint.
- TCA is the sole cause of wine taint.
- The world's cork supply is shrinking, requiring the development of synthetic closures to meet market demand.

Fact: Each year nearly 20 billion bottles of wine worldwide are sealed with corks. Cork is a natural product with physical characteristics (flexible, resilient, impermeable to liquid, relatively high oxygen barrier) ideally suited to preserving bottled wines. Cork interacts with wine, but this interaction is not inherently negative.

A wine could be affected by conventional cork because of its naturally internal heterogeneous structure: varying permeability from cork to cork, variable tannic contribution depending on the corks' origin, number of lenticels (superficial cork cracks) depending on cork quality, and lignin incrustations which are susceptible to host chemical reactions leading to the formation of chloroanisoles. Conventional cork also can absorb external contaminants.

Fact: Conventional corks are a source of TCA-related taint in already-bottled wine. Wines can also become tainted before bottling. This can be due to TCA, other chloroanisoles or other taints. Analyses performed on tainted wines in Bordeaux in 1999 showed that 25 percent were caused by sources other than cork.

Tainting of already-bottled wines can be linked to bottling equipment and/or empty bottles. Tainting of wines prior to bottling can originate in a variety of sources including vineyards, wooden structures in wineries, oak barrels, tanks, processing materials, wooden pallets and cardboard. The macro-environment in which wines are produced is susceptible to this unfortunate phenomenon.

The interaction of certain environmental parameters can lead to airborne contamination. When TCA in wine is accompanied by higher concentrations of PCA (pentachloroanisol) and TeCA (Tetrachloroanisol), the most likely primary taint source is 'treated' wood or a possible airborne contamination in the cellar or storage areas.

Fact: Cork is a highly reliable and effective bottle-sealing agent that effectively preserves the integrity of wine by inhibiting improper oxidation. Alternative closures do not match all the physical performance of cork, nor have they been proven effective or reliable for long-term aging of wines.

Fact: Synthetic closures and screw caps are less susceptible than conventional cork to the acquisition and transmission of miniscule amounts of TCA. Wine taint, however, is not necessarily related to the presence of TCA. Wines can be tainted by improper oxidation, by reduction, or by the introduction of other external unpleasant aromas and flavors. "TCA-free" is not necessarily synonymous with "taint free." Anything that comes in contact with the wine - barrels, pallets, shipping containers - can transmit a taint. Synthetic stoppers can also transmit a range of volatile synthetic substances into the wine. There have been reports of reduction in wine sealed with screw caps. Both screw caps and synthetic closures can therefore contribute to tainting a wine, even without the presence of TCA.

Fact: It can sometimes be difficult to insert a corkscrew into a synthetic stopper. Synthetic stoppers can be difficult to remove. The jagged metal edges on screw caps can also be a slight hazard after opening. And the use of cork is more environmentally friendly than its counterparts. The bottom line, however, may be that most consumers associate cork with quality wines.

Fact: The detection of TCA at extremely low levels is based on a perception of a sensory “difference” rather than a recognizable “taint.” Even so, detection of a sensory difference at low TCA levels, (say, less than 5 ng/L), would require an experienced and talented taster, an odor-free and distraction-free venue and a sample of the pristine wine for comparison. The level of TCA at which a recognizable taint can be detected under ordinary circumstances is much higher and depends somewhat on the type and style of wine being tasted. Typically, TCA levels of 5 ng/l for a light white wine up to 10 ng/l for a full- bodied barrel-aged red wine are considered minimum thresholds for detection. Increasingly sensitive analytical methods (SPME/GCMS) have contributed to analytical detection thresholds that can be as low as 0.5 to 1.0 ng/l. At these exceedingly low concentrations, there is no verifiable correlation between a sensory perception of taint and analytical findings.

The Australian Wine Research Institute (AWRI) report on closure performances reveals the tenuous and inconsistent link between extremely low levels of TCA and the sensory perception of taint.

Fact: Most consumers know little, if anything, about TCA taint in wine, though that may be changing due to increasing publicity in the consumer media about wineries experiencing TCA challenges in their physical facilities. However, most consumers evaluate the quality of a wine according to their own expectations and experience with wine. Some discerning consumers readily detect flaws in wine, which may or may not be attributable to TCA. Unfortunately, media coverage about TCA, wine defects and generally unpleasant sensory characteristics is often called "cork taint," whether accurate or not.

Fact: Since cork in its raw form is naturally heterogeneous, the risk of taint in conventional cork is random and therefore a quality control challenge for conventional cork producers. The minute quantities of TCA involved, and the comparative rarity of any contamination, pose a real challenge for analytical and sampling procedures. To suggest that conventional cork suppliers and winemakers can easily locate and control all of the myriad potential sources of chloroanisole contamination is unrealistic. That said, significant breakthroughs have occurred. DIAMANT, for example, has been proven to remove TCA to undetectable levels.

Fact: Consumers already accept bulk wine in boxes and with non-cork closures. Will consumers accept such packaging for all wines? While it is fair to say that consumers generally pay attention to the closure only when they perceive a problem with the wine, most associate cork with quality wines.

Fact: Twenty to 25 years ago, when reported taint problems first increased, there was no validated empirical evidence linking taint to conventional corks. Moreover, these complaints rarely surfaced until some time after bottling. The conventional cork industry and others gradually developed a deeper understanding of the situation, although the full picture is still not complete and much remains to be learned. With DIAM, OENEO has achieved the highest level of security available in the industry. The DIAMANT process eliminates over 150 pollutants directly from the raw cork material, including removing TCA to undetectable levels.

Fact: The preliminary closure study noted that synthetic stoppers "appeared least consumer friendly," were least likely to protect the wine from oxidation (or to retain SO2), and that although the screw cap generally performed well, wines sealed with screw caps developed a slight rubbery/sulfide odor. Surprisingly, the AWRI protocol did not include TCA analyses of wines sealed with plastic closures and screw caps that showed musty, TCA-like aromas. More recent AWRI results, however, have addressed reduction issues related to screw cap closures and have been highly favorable to OENEO's new technological corks treated with the Supercritical CO2 extraction process.

Fact: Protecting wines from taint demands constant vigilance. Synthetic stoppers and screw caps can attract and transmit taints, although they are less vulnerable to TCA than cork. There has been one recorded case of contamination of a plastic-sealed pharmaceutical product by TBA (tri-brom-anisole), and there have been many reported cases of plastic films in flexible packages causing TCA contamination. Some synthetic materials can contribute to "flavor scalping" (modification of a wine's aromatic profile by the absorption of wine flavor compounds), and other negative factors, including oxidation and reduction, and can cause wine taint.

Fact: In his book, Le Goût du Vin, author Emile Peynaud devoted some 2,000 words to describing the various taints that he encountered in wines. The book was published in 1980, and there was no mention of TCA, although "cork taint" was mentioned briefly. A wine can be tainted without TCA, and wine with TCA is not necessarily tainted. Wines can also be tainted by oxidation, by reduction or by the introduction of other external unpleasant aromas and flavors. Anything that comes in contact with the wine - barrels, pallets, shipping containers - can transmit a taint. Synthetic stoppers can also transmit a range of volatile synthetic substances to the wine. Both screw caps and synthetic closures can therefore contribute to tainting a wine, even without the presence of TCA.

Fact: This argument is entirely without merit or factual basis. Indeed, the worldwide supply of raw cork is increasing to match the demand for natural corks. Over the last 15 years, more than 150,000 hectares (370,000 acres) of new cork trees have been planted, providing a reliable and stable cork supply for future cork production. Cork production is expected to increase by 2010 by approximately 30,000 tons/year, representing a 15 percent increase over today's production levels.