Is It Really Corked or Is Trichloroanisole (TCA) a Scapegoat?

As an aerospace systems engineer, I deal with a lot of problems and issues.  In this role, it is very important to review all of the details and facts before presenting results to management and customers.  Most of you know my love of natural cork closures for wines.  However,  I have many colleagues and friends that love screw caps as an alternative.  I am not going to write another article on the pros and cons of these two closures as this topic will always present a difference of opinion.  The most important thing is to make sure to review "ALL" of the facts and details when trying to determine the source of TCA that has caused a wine to be truly corked.

General consensus is to always blame the cork as the source of TCA in wines when that musty, wet paper or cardboard smell is noted.  Reality is that the general public cannot detect TCA below 6-8 nanograms/liter.  There is a very small percentage of individuals with a very keen sense of smell and taste that can detect TCA at around 2 nanograms/liter, but these are a select few and are by no means the majority.  TCA in natural cork has been reduced dramatically over the years via new technology and cleaning/sanitizing processes.  Laboratories are now using Gas Chromatography Mass Spectrometry (GCMS) to identify trace chemicals,  such as TCA,  to levels as low as 0.5 nanograms/liter.

Cleaning and sanitizing processes have been changed to remove chlorine based products used for the corks and wine processing equipment. The United Cork Council have actively performed laboratory tests over the years on corks for TCA using high-tech calibrated equipment, providing measurable data or metrics and statistics on the effectivity of TCA removal from natural cork.  But why does no one look beyond the cork if a wine is tainted with TCA?  Generally, it is felt that they have found the smoking gun since the bottle used a natural cork and therefore, come to the conclusion that eliminating cork closures will end corked wines.  Many times I feel that people detect chemical abnormalities other than TCA in a wine and immediately say it is corked.  This provides another possibility to inaccurate TCA statistics based on human senses.

What about cases where wineries have been found to be the source of TCA and not a cork enclosure?  Does anyone factor this into the equation?  Four wineries that have suffered from TCA, where corks were not the cause,  were Hanzell,  Chateau Montelana,  Beaulieu Vineyard and Gallo.  If there are four I am sure there are others.  In the case of Hanzell, the winery was shut down for 6 months to find the cause of TCA in their wines.  The source of the TCA was found to be two of the original transfer pipes that were about 50 years old.  These pipes were stained purple stemming from years of use within the winery.  So here is a situation where it doesn't matter what type of closure is used for the bottles, TCA taint is present in the wine itself.  Placing wine from any of these four TCA plagued wineries into corked bottles will inadvertently make the cork closure a scapegoat.  Jumping on the bandwagon becomes an automatic conclusion rather than pursuing additional research to determine the actual root cause of the TCA source.  This lack of true statistics and understanding is one of the prime drivers being used to switch to screw caps and eliminate cork closures.  Now comes this scenario...what if these four wineries used screw caps as opposed to natural cork what would the conclusion be?  Would the wine be looked at as the source or would the wine world now have a new term that the wine was "capped"?

The one thing to remember with issues like TCA is that you need to look at the big picture.  If you are only researching a problem based on what is perceived to be the smoking gun you are masking or possibly covering up the real source of the problem.  If you want to do due diligence the wine must be tested pre and post bottling to validate the true source of the TCA.  Corks are already screened through new processes that have been put into place by the Cork Council at cork producing facilities.  Christian Butzke, PH.D. of the Associate Professor Food Science, Purdue University Stated in his article Cork Taint, " The habit of blaming cork may explain why estimates of TCA contamination based on anecdotal evidence range from 2 percent to 10 percent and above.  But a large and growing amount of hard evidence concludes that the incidence of TCA has dropped precipitously in recent years and is commonly measured at less than 1 percent of wines sealed with real cork."

So whatever you do make sure that you look at the BIG PICTURE and all of the possibilities before drawing a conclusion.   As these aforementioned wineries discovered they in fact were the culprit and not the cork.  Something that I'm sure came as a shock to a lot of people in the wine world as well as the wineries themselves.  In these instances the scapegoat, being the cork, was vindicated however the disagreement on closures in wine will go on for years to come.


Rusty Sly