The Impact of Compounds Extracted from Wood on the Quality of Alcoholic Beverages

Abstract

The production of some alcoholic beverages very often requires the use of wood from various tree species to improve the quality parameters (smell, taste, and color) of the drink. The review discusses the types of wood used in the production of wines, beers, and flavored vodkas. Changes occurring in wood during the process of toasting barrels or wood chips are described. The compounds derived from wood that shape the aroma, taste, and color of alcoholic beverages are presented. Depending on their origin, they were classified into compounds naturally occurring in wood and those formed as a result of the thermal treatment of wood. Next, the influence of the presence of wood on the quality of alcoholic beverages was described, with particular emphasis on wine, beer, whisky, and brandy. The final part of the article presents innovative techniques using wood to impart qualitative features to alcoholic beverages.

Sources of Volatile Aromatic Congeners in Whiskey

“…This has resulted in various experiments with other woods, such as cherry wood, acacia, and chestnut, among others. Tarko et al recently highlighted the potential for various compounds in differing wood types, with high levels of eugenol and isoeugenol in chestnut wood and further variances in cherry wood and acacia [126].…”

“…In some cases, casks are heated, toasted, or charred (Figure 7). Cask heating breaks down wood polymers to: (i) enhance the extraction of flavor compounds; (ii) degrade undesirable wood-derived flavor components; or (iii) create a layer of active carbon from intense charring, a more vigorous burning of the wood to a point where the surface breaks and the interior of the cask blackens [11,115,126]. Cask heating imparts sweeter and smokier flavors by promoting more vanillin and phenol generation from lignin and tannin degradation [112,115].…”

“…The compounds produced are both time-and temperature-dependent. Light toasting is performed at approximately 120 • C for up to 90 min, medium toasting between 120 and 230 • C, and high toasting >230 • C for more than 15 min [126]. Lignin degradation is initiated via stronger and more prolonged toasting, creating higher concentrations of key volatiles such as phenols, phenyl ketones, and aldehydes such as syringaldehyde, coniferaldehyde, and vanillin (Figure 8) [11,38].…”

“…These cinnamaldehydes possess a double bond in the side chain and are further oxidized to benzaldehydes (vanillin and syringaldehyde) [115,128]. These aromatic aldehydes are thought to be markers of a better-quality spirit; their concentration is dependent on the type of cask and degree of charring, as these affect compound extraction and alcoholysis of the lignin [126]. Excessive cask heating can result in increased concentrations of phenols, such as guaiacol and syringol, which have more smoky, medicinal, and spiced characteristics that can overpower and dominate the flavor of whiskey [11].…”

“…Correspondingly, heat treatment of oak aids lactone extraction, which derives from the thermal degradation of lipids in the wood. Light to medium toasting is often used to extract lactones as they are commonly found in the heartwood of the oak, and light toasting only affects the top 2 mm layer due to the poor thermal conductivity of wood [126]. Two key lactone isomers of interest are known as oak or whiskey lactones: cis and trans β-methyl-γ-octalactone [115].…”