Evaluation of a Quality Control Tool for Predicting the Distribution of 2, 4, 6,- Trichloroanisole (TCA) in cork populations and bottled wines

2,4,6-trichloroanisole (TCA) released by natural cork closures in wine-based soaks,
“Releasable TCA” (RTCA), was studied. Corks imported into California from Portugal
were taken from 10 different bales provided by seven different cork suppliers. For each
bale, 10 bulk soaks of 50 corks each were performed and RTCA measured.
Simultaneously, 100 corks from each bale were soaked individually and RTCA measured
in each individual soak. Data obtained were used to show distribution of RTCA in
individual corks within bales, and to provide comparisons with RTCA measured in bulk
soaks. RTCA in the 50 cork bulk soaks ranged from less than 0.5 to more than 20 ng/L
across the ten bales. CV?s for the replicate soaks were high, ranging from 14 to 120%.
Error in bulk soaks was strongly influenced by high outliers. Distinct population patterns
were found in the individual cork soaks. Some bales having only 1%of corks greater than
2.0 ng/L and others with more than 18%greater than 12 ng/L. Despite their high
variability, bulk soak values were correlated with individual cork soak averages and with
proportions of individual corks with high RTCA, therefore providing valuable
information. Consequently, the implementation of this test in QC programs has the
potential to dramatically increase the general quality of the corks screened.