​

So where is TCA coming from? This is exactly the issue confronting a large number of wine makers worldwide. It is revealing to review the issue in Australia where screw cap is used nearly exclusively in cheaper wines. In 2015/16 the number of taint investigations reached 61 an all-time high and 6 times higher than its low in 2012/13 [1] when cork was much more prevalent. Of the 61 taint investigations 25% were TCA making it the single biggest problem but cork was not involved [1].

 

Winery water was the source of the TCA contamination [1] and it can concentrate in cross flow filters when flushed with water for cleaning [1]. Filter presses are also at risk. The TCA is later released to the wine during filtering. If the filter is in the bottling line then the first bottles are more contaminated than the last. The Australian industry was quick to act with newsletters and workshops across the country to inform wine makers of the problem. TCA may not seem a problem in the water but it concentrates where ever it contacts plastic, wood or filter material that later contacts wine.

 

Interestingly TCA contaminates almost all water that is sourced from reservoirs, dams and water ways. It is naturally occurring, readily produced by ubiquitous filamentous fungi [2] and addition of chlorine is not necessary because it is present before that purification process [2] but chlorination does add to the problem. Municipal drinking water is often found to contain up to 2 ng/l of TCA. [2]

 

Perhaps we should hear more often “Waiter this wine is filtered!”

​