Understanding wine sorption by oak wood: Modeling of wine uptake and characterization of volatile compounds retention

Abstract

Cooperage wood is a porous material and beverages exchange compounds with it by penetrating into its pores. This work demonstrates the enrichment of wood with wine during ageing. Three oak varieties were cut into different sized chips and immersed in fortified wine and water. Wine and water uptake were measured along time and sorption was described based on a saturation empirical model. Maximum uptake varied among wood types and was independent of particle size, which affected only equilibrium time. Sorption of wine volatiles such as alcohols, esters and acids in wood was shown, which was also dependent on wood type and independent of particle size. Multivariate analysis demonstrated differences and similarities in depletion of wood extractives and sorption of wine volatiles depending on wood variety. Sorption shown in this work demonstrates wood as a vector for aroma recombination, when reused for ageing between different beverages.

Factors affecting extraction of adsorbed wine volatile compounds and wood extractives from used oak wood

“…Unaged fortified wine utilized for the preparation of the used oak woods was kindly provided by Quinta do Portal S.A., with an ethanol content, by volume, of 20.9% ± 0.3%. Before contact with wood, unaged fortified wine didn't have any content in wood extractives, being its composition reported in Coelho et al (2019). Toasted French oak (Q. robur) 950 × 50 × 18 mm 3 and toasted American oak (Q. alba) 950 × 50 × 6 mm 3 staves, from the Oenostave® series (kindly provided by Seguin Moreau, France), were used in this work.…”

“…Staves of both varieties were supplied with the M+ toasting level, that in cooperage corresponds to a 68 min toast at 62°C ± 3°C without water addition (Chira & Teissedre, 2014). Toasted American and French oak without any prior usage did not have any content in wine volatile compounds, which where adsorbed during contact with fortified wine as reported in Coelho et al (2019), where compositions of unused and used woods are presented.…”

“…Besides becoming depleted of extractives, wood also becomes enriched with the beverage composition. Several different families of compounds were found to adsorb onto wood during contact, namely monomeric volatile phenols (Barrera-García, Gougeon, Voilley, & Chassagne, 2006) polyphenols, namely monomeric anthocyanins, (+)-catechin, (−)-epicatechin, gallic acid, and trans-resveratrol (Barrera-García et al, 2007) and wine volatile compounds, namely terpenes, alcohols, esters, aldehydes, norisoprenoids and acids (Coelho, Domingues, Teixeira, Oliveira, & Tavares, 2019;Ramirez et al, 2001). Several mechanisms were proposed for interaction of wine compounds with wood.…”

“…Sorption of these compounds was found to be dependent both on wood macromolecules and on sorbate chemical structure, with lignin demonstrating selective adsorption, involving mainly hydrophobic interactions (Barrera-García et al, 2008). In recent works, focusing also wood sorption of wine compounds, the importance of mass transference was demonstrated in the uptake of wine by wood, accompanied by the identification of the wine volatiles adsorbed (Coelho et al, 2019). However, the adsorption mechanism of wine volatile compounds to wood remained to be confirmed, on the basis of the previously mentioned works.…”

Modeling of absorption process of the water by the wood in two-dimensions

“…The second aim of this work is to build and check a numerical model able to describe the absorption process in two dimensions, when the water content is above the fiber saturation point. Some models have been successfully applied in cases where the water content is above the fiber saturation point in onedimensional transfer [8][9][10][11][12] .…”