I have written extensively about TCA and related haloanisole taints in wine - there 60 pages on the topic in my book 'Wine Faults and Flaws: A Practical Guide'. There is no doubt that incidences of affected wines peaked in the late 1990s and early 2000s, and were in decline since then. However, in the last year, I have once again encountered numerous tainted bottles, suggesting that the problem is again on the rise.
I keep notes about the condition of wines at all the tastings I attend, and wineries visited. The rogues' gallery, the 'bottom of the league table', of the most encountered faults so far this year is:
1. Reductivity - volatile sulfur compounds, including lightstrike.
2. TCA and TBA taints - usually and often erroneously often referred to as 'corked wines'.
3. Brettanomyces related faults, particularly volatile phenols.
The odours associated with each of these faults are well documented. However, a major concern is that at a 'low' level, the compounds responsible for TBA/TCA taints are not picked up on the nose as taints, but an affected wine is very flat, and seems to have all the fruit stripped out of it.
These haloanisole compounds can contaminate a winery, and migrate into wines produced. This year, at two of the wineries I visited, I was aghast to find hypochlorite bleach being used as a cleaner/sanitiser. The compound is unstable in solution, and releases chlorine gas. The presence of 2,4,6-TCP, the precursor of TCA, has been traced in many winery facilities to the use of chlorine bleaches, in some case such use having ceased years previously. My nose is sensitive to haloanisoles, and during the winery visits I was are of airborne contamination in three vat rooms, and five barrel rooms, including one at a Bordeaux Grand Cru Classé.
Barrels, particularly pre-used barrels can be a source of chloroanisoles and their precursors. Coopers, having become aware of the risks not only to wines but also their own reputations, have increased diligence and changed working practices to reduce the risk ofhaloanisole
contamination. An interesting tool in the battle against TCA and 2,4,6-TBA in cooperage, is the employment of sniffer dogs! TN Coopers, an international barrel-making company, developed the 'Natinga Project' involving Labrador Retrievers, known for their highly sensitive noses (at least10 000 times more powerful than humans) to seek out haloanisoles pre-cooperage and in finished barrels pre-despatch to clients.
So, the war against TCA/TBA in wine is far from over. However, with unprecedented diligence at the major cork producers, the battle lines have been re-drawn.
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