Identification and Prevention of Haloanisole Contamination The Problem: Haloanisoles in production or storage areas can contaminate wines.
Three haloanisoles can cause “musty” odors in commercial wines:
- TCA (2,4,6-trichloroanisole)
- TeCA (2,3,4,6-tetrachloroanisole)
- TBA (2,4,6-tribromoanisole)
TCA is generally associated with “cork taint“, but despite what is often believed, haloanisole contamination is not limited to corks, and may originate in wine by various pathways. Preventive Actions and Tools:
ETS has developed sampling and analytical tools to help wineries investigate causes of haloanisole contamination and to develop preventive programs. Screening Commercial Wines
Wineries can investigate the status of their wines in the marketplace by running the Haloanisoles Panel on a selection of bottled wines. If haloanisoles are detected at levels of concern, further investigations can be conducted to determine if contamination could have occurred in the cellar. Screening Cellared Wines
Contamination of cellared wines by haloanisoles is seldom obvious. Sensory perceptions are quickly impaired by constant exposure to airborne haloanisoles.
If haloanisoles are found in cellared wines, an in-depth screening of wine lots stored in the cellar can determine the extent of the contamination and serve as a starting point for identifying the origin of contaminants.
An economical method to monitor cellared wines is to conduct a systematic analysis for haloanisoles as part of the routine pre-bottling QC. A pre-bottling sample also establishes a “base level” of chloroanisoles for a wine prior to the use of corks or other packaging materials. Finally, release of contaminated wines in the marketplace can be prevented. Checking Possible Sources of Contamination
In a cellar with haloanisoles, it is imperative to find the source of contamination and to determine the range of contaminated materials. Various materials can transfer haloanisoles to wine by direct contact. Contamination can also be caused by airborne haloanisoles.
Haloanisoles can be found in water supplies. The Haloanisoles Panel can monitor the status of the winery water supply and can often trace a contamination back to its source. PREVENTION TIP:
Running the Haloanisoles Panel on a water system is especially important if a specific risk is suspected such as wood storage tanks or heavily chlorinated water. Winery Atmosphere
Once present, haloanisoles can quickly spread throughout a facility due to high volatility and the ability to be absorbed by solid materials. Airborne chloroanisoles can contaminate wines through brief exposure to the winery atmosphere. Examples include crushing, open top fermentations, pump-overs, punch downs, rackings, and barrel aging.
Atmospheric haloanisoles are easily checked using “atmosphere traps”. The absorbent trap is exposed to the air in specific locations in a facility and subsequently analyzed for haloanisoles. Atmosphere traps can identify areas with haloanisole contamination and can often point to a potential contamination source. PREVENTION TIP:
Many wineries now routinely monitor their cellars using atmosphere traps. The frequency depends on past history and potential risks. The atmosphere traps provided by ETS are extremely sensitive tools. They may detect atmospheric haloanisoles before they pose a risk to wines. Wood Material
A wide range of wood material may be present in a winery or cellar. Structural wood such as beams, rafters, plywood panels on walls or ceilings, pallets, tank stands, barrel structures or runners, and cooperage may contain halophenols and/or haloanisoles. Halophenols are converted to haloanisoles by microbial activity.
Wood that has been exposed to chlorine is likely to contain TCP (2,4,6-trichlorophenol), the precursor of TCA. This occurs in facilities where chlorine-based sanitizing agents have been used, even if the agents had no direct contact with the wood.
Wood that has been exposed to a pentachloro-phenol-based preservative generally contains TeCP (2,3,4,6-tetrachlorophenol), the precursor of TeCA. The use of “penta-based” preservatives is now restricted, but they are still found in various wood materials. TBP (2,4,6-tribromophenol), the precursor of TBA (2,4,6-tribromoanisole), is used both as a wood preservative and flame retardant. It can be found in wood, but also various plastics or other synthetic polymers.
Any wood material can be analyzed at ETS Laboratories for haloanisoles and halophenols. PREVENTION TIP:
Analysis of wood samples can identify existing sources of haloanisoles as well as potential ones. (halophenols not yet converted to haloanisoles). “Composite” samples (e.g. representing a ceiling, barrel supporting structures, or groups of wood tanks) can be used as a screening tool. This document is a compilation of information and views from various sources provided for the convenience of our clients. Information in this document is provided "as is" without warranty of any kind, either expressed or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and freedom from infringement. User assumes the entire risk as to the accuracy and the use of this document. This document may be copied and distributed subject to the following conditions: 1) All text must be copied without modification and all pages must be included; 2) All copies must contain ETS's copyright notice and any other notices provided therein; and 3) This document may not be distributed for profit. All trademarks are acknowledged. Copyright © ETS Laboratories 2001-2010.