Absorption of 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) from wine by bottle closures

The content of TDN in Riesling wines has become an actual topic due to the global climate changes. Being a controversial aroma compound from the consumers' preference perspective, TDN requires tools of its management in wine. Previously it was shown, that different bottle closures are able to scalp significant amounts of TDN from the wine. In the current work, the rate of TDN absorption process was investigated. Bottles with the TDN spiked wine and five types of closures were stored at various conditions. It was found that besides the time of storage, bottles position and storage temperature can have a considerable impact on the rate of the TDN scalping process. Synthetic, micro-agglomerated and glass stoppers were able to absorb a major part of TDN, however, with a different rate. Thus, the slowest scalping process was observed for the glass stoppers due to a small contact surface of the plastic sealing ring with the wine. The difference in the amount of absorbed TDN after 3 months could reach more than two times for synthetic or glass stoppers depending on the storage conditions. For example, vertical bottles position and lower temperature favored faster TDN absorption. Cork stoppers demonstrated quick scalping process independently of the storage conditions, however, only a limited amount of TDN (less than half) could be absorbed. In case of BVS screw caps, only a minor decrease of TDN in the wine was observed in all the variants.