Cork Taint (Trichloroanisole TCA) and How to Prevent It
What is Cork Taint?
Cork taint, scientifically known as trichloroanisole (TCA), is one of the most prominent organoleptic defects found in wine. Cork taint occurs when undesirable aromatic compounds within the cork material are transferred into the wine after bottling, causing an unpleasant musty, mouldy, or powdery aroma that alters the wine’s sensory profile. As trichloroanisole is not naturally present in grapes or wine, cork taint is considered a contamination, rather than a spoilage, and develops within cork and wood products.
How to Identify Cork Taint?
The simplest process to identify cork taint is through scent. Often TCA will produce a musty, powdery, or dry smell akin to wet newspaper or old wood. This distinctive scent is associated with the term ‘corky’ or ‘corked.’ The ability to detect cork taint via aroma is dependent on the individuals’ sense of smell and the style and variety of the wine. Fuller bodied wines with powerful aromatics, such as cabernet sauvignon, require significantly higher levels of trichloroanisole to be detected by scent, whereas the presence of TCA in lighter wine, such as pinot noir, the aroma can be detected at much lower levels.
Some aromatic characters, such as earthy & mushroom aromas are not necessarily a result of the presence of TCA. Unwanted aromas could also be caused by powdery mildew or other moulds on the grapes. This necessitates the need for testing of the wine to rule out alternative causes.
What Causes Cork Taint in Wine?
Cork Taint is caused by the formation of trichloroanisole (TCA) which occurs when fungi or mould that is naturally present in the cork or wood comes into contact with chlorophenols that are formed through the combination of phenols in the wood and contaminants containing chlorine, or present in fungicides and wood preservatives. The fungi then converts the chlorophenols into TCA, resulting in an unpleasant odour.
The contamination of trichloroanisole can be observed in other wood products such as barrels or wooden pallets, within the winemaking facilities, or during the transit of wooden products, especially if chlorine-based chemicals are present as cleaning agents. To combat the formation of cork taint, Classic Oak Products do not recommend the use of chlorine within wine making facilities and care should be taken when handling barrels and other wood products.
At Classic Oak Products, our suppliers uphold extensive preventative measures to limit the availability of essential precursors in the formation of cork taint within their products in accordance with TFF standards. These preventative measures can be observed within the sourcing of materials, the production of the products, the manufacturing facilities, and the transit of products. To learn more about how we can deliver the highest quality wood products for your wine making needs, contact your local team member.
The Effect of Cork Taint on Barrels
Similar to corks, wooden barrels are susceptible to fungi or mould which could come into contact with chlorine-based substances from cleaning materials, water treatments, or nearby materials that can cause TCA to form. Once formed in the barrel itself, TCA can then leach into the wine stored inside during ageing, modifying the wine’s aroma. Due to the significant impact that the presence of trichloroanisole has on a wine’s aromatic profile, when a barrel is contaminated, it is extremely difficult to eliminate the damage, often resulting in the loss of the entire contents inside the barrel.
The spread of TCA to other barrels, corks, and surfaces, can occur throughout a winery if the source of the contamination is not identified and quickly removed. To prevent the damage of TCA from occurring, and to uphold the quality of the wine, wineries and cooperages must be careful to maintain preventative practices.
How to Prevent Cork Taint
How our Cooperages prevent Cork Taint
At Classic Oak Products, our suppliers uphold preventative measures to mitigate the likelihood of contamination in accordance with TFF standards. The use of any and all chlorinated products is forbidden within the facilities of all TFF members. To prevent contamination from water pipes, TFF suppliers do not spray the wood. All stave-wood is naturally dried without any water and any water used within the cooperages, such as tapped water or scalding water, is filtered with a carbon filter. Staves are stored on natural untreated oak wood pallets and the facilities are heated through an outside wood boiler using wood chips from the workshop. The oak wood used for toasting is sourced from the off cut of the staves.
To reduce contamination during transportation, our barrels are not mixed with other coopers barrels in delivery containers. Containers are constantly visually checked and must be compliant, tight, clean, dry and odourless, and are systematically rejected otherwise. A plastic liner is used on the floor to avoid any contamination.
Atmospheric analysis occurs several times per year at the workshops, including analysis of the water, pallets used for the storage of barrels, and packaging. Statistical analyses are also made of the green wood and the barrels to reduce risk.
How to Avoid Cork Taint in your Winery
Concern for both the materials used throughout the winemaking process and the external environment of the winery must be considered to help prevent cork taint in your winery. Winemakers should ensure their corks and wood products are purchased from high-quality and trustworthy sources and avoid any materials that have been treated with chlorophenol compounds (including building materials). To learn more about how our quality wood products can help ensure the prevention of cork taint, speak to your friendly local team member at Classic Oak Products today.
Chlorine-based products such as cleaning products must be avoided and the water supply should be carefully managed and tested on a regular basis to reduce the likelihood of cork taint contamination. The cleanliness and dry storage areas of both equipment and wood products are also essential preventative measures at winemaking facilities. Wet and damp environments are breeding grounds for mould which is a key contributor to TCA occurring. For the best barrel care in reducing the likelihood of cork taint contamination and increasing the longevity of your barrels, Classic Oak Products recommend an initial inspection of your barrels on delivery for signs of contamination by sight and smell. A further full inspection of the barrels should be undertaken after the packaging is removed before the barrels and all wood products are properly stored in a dry and clean environment.
Despite all efforts, there is no concrete way to completely eliminate the risk of cork taint from occurring within your products.