This study examined the sealing effectiveness of different closures on the permeation of exogenous compounds when bottled wine model solutions were stored in a contaminated environment with deuterium-labeled 2,4,6-trichloroanisole (d5-TCA). Wine model solutions and closure fractions (outer, middle, and inner) were assessed over time for the concentration of releasable d5-TCA by SPME-GC-MS. During 24 months of storage, high concentrations of d5-TCA were essentially retained in the outer portions of natural and microagglomerate corks. Under the conditions of this experiment, the natural and microagglomerate cork stoppers were effective barriers to the transmission of exogenous contaminants. Conversely, d5-TCA penetrated synthetic closures and contaminated the wine. (We recommend that you consult the full text of this article).