PRINT THIS PAGECapone, D., Sefton, M., Pretorius, I., & Hoj, P. (2004). Flavor 'scalping' by wine bottle closures. Practical Winery and Vineyard, pp.44-55.
This paper looks at the impact of the closure on wine aroma and flavour.
Many of the volatile flavour compounds released during vinification, maturation and storage are formed from involatile grape derived precursors. In addition wines may contain volatile oak constituents pick up during storage.
The impact of TCA and related compounds, derived from corks, on bottled wine quality is well-known.
AWRI looked at whether closures could be modifying the product quality by absorbing aroma compounds. This process is known as flavour scalping.
A trial was carried out using wines spiked with a number of volatile compounds. The wines were bottled using several of the closures types used in the AWRI closure trial. Control wines were sealed in glass ampoules. The wine was stored for two years at between 13°C and 23°C.
After two years there was no evidence of any flavour scalping by ROTE (Stelvin) closures when compared with the controls.
No flavour scalping was detected with any of the closures for isobutyl methoxypyrazine (responsible for herbaceous characters in wine) or for any of the added oak related compounds.
The concentrations of fruity esters that were added changed in the control wines with some of the compounds increasing and others decreasing.
Some of the levels of these esters were affected by the types of closure used. The amount of absorption increased with increasing ester chain-length.
No absorption was observed with the ROTE closures. Absorption was greatest with the synthetic closures absorbing up to 70% of some esters.
The effects on TDN, the grape derived hydrocarbon responsible for the kerosene like flavour in some wines was very closure dependent. All synthetic closures removed between 96% and 98%, the natural cork 50% and ROTE none. Excess levels of TDN in wine can be seen as being undesirable.
Reviewed by Nick Sage - September 2004