Rapid Induction of Ageing Character in Brandy Products – Part I. Effects of Extraction Media and Preparation Conditions

Minnaar

2016

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As part of a broader study that investigated techniques for the rapid induction of the needed ageing character in brandy products, the effect of oak type on quality and chemical composition of oak wood extracts and matured and unmatured potstill brandy, is reported on. Extracts, prepared from American and French oak chips supplied by a South African cooper, and from commercially obtained oak, and representing different levels of toasting, were added to 70% (v/v) unmatured pot-still brandy and stored for eight months in glass containers (Schott bottles) at room temperature, or in the case of controls, below 0°C. Matured and unmatured (control) pot-still brandy samples were analysed for wood-derived congeners by means of HPLC and GC. Although French oak initially yielded better quality products, these effects lost prominence and, after eight months maturation, yielded similar sensory quality to American oak. French oak samples had higher concentrations of wood-derived congeners (including eugenol, the furan derivatives and aromatic aldehydes). However, the American oak generally contained higher concentrations of oak lactones than their French counterparts, with higher proportions of the more sensorially potent cis-form of lactone than its trans-isomer.

Section: Methodsmentioning

confidence: 99%

“…This is the second in a series of articles (Van Jaarsveld et al, 2009). The first article concerned the importance of extracts in brandy maturation, the preparation of oak extracts, the influence of different extraction conditions and mediums, and suppliers of oak chips on chemical and sensory profiles.…”

mentioning

confidence: 99%

Rapid Induction of Ageing Character in Brandy Products – Part II. Influence of Type of Oak

Minnaar

2016

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“…Materials and methods have already been described in part I (Van Jaarsveld et al, 2009). Briefly, American and French oak chips, representing different levels of toasting and obtained from a cooper and a commercial supplier, were placed in either water or a 55% (v/v) ethanol medium and boiled under reflux with backflow cooling for 5 hours.…”

Section: Methodsmentioning

confidence: 99%

“…Large variation in the data may be attributed to factors that impact on the type and number of compounds extracted from the wood (Van Jaarsveld et al, 2009). In addition, each oak species displays high variation between individual trees.…”

Section: Figurementioning

confidence: 99%

Rapid Induction of Ageing Character in Brandy Products – Part III. Influence of Toasting

Minnaar

2016

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As part of a broader study that investigated techniques for the rapid induction of the needed ageing character in brandy products, the effect of oak wood toasting on quality and chemical composition of oak wood extracts and matured and unmatured pot-still brandy, is reported on. Extracts, prepared from oak chips supplied by a South African cooper, and from commercially obtained oak, and representing different oak types and levels of toasting (i.e. untoasted, light, medium and heavy), were added to 70% (v/v) unmatured pot-still brandy and stored for eight months in glass containers (Schott bottles) at room temperature, or in the case of controls, below 0°C. Matured and unmatured (control) pot-still brandy samples were analysed for wood-derived congeners by means of HPLC and GC. Toasted, as opposed to untoasted oak, gave acceptable extracts, the best overall quality pot-still brandies and generally higher concentrations of volatile (GC-determined) and less volatile (HPLC-determined) wood-derived congeners. Toasting provoked an important separation as indicated by discriminant analysis.Oak wood chemistry is complex because different flavour-affecting compounds are produced at different temperatures. Oak types also toast differently. American oak, which is denser and has coarse grain, toasts faster than fine grained European oaks (Caputo, 2004). Barrel making involves oak seasoning and toasting, which ensure the structural integrity of the barrel. Seasoning prevents the wood from shrinking after barrel construction and hence leakage, while firing is applied to stabilise the curved shape of the barrel. Both these fabrication steps also play important roles in oak flavour development. The application of coopering heat disrupts chemical bonds within the wood polymers cellulose, hemicellulose and lignin and results in degradation or compositional changes by pyrolysis and hydrothermolysis. These changes can influence the flavour of wine and spirits significantly. In addition, major changes take place in the structure and level of oak tannins (Hale et al

“…Vanilla Lebrun, 1991;Lee et al, 2000Guaiacol Smoky Lebrun, 1991Sefton et al, 1993;Cerdán et al, 2002 4-Methylguaiacol Smoky Lebrun, 1991;Sefton et al, 1993;Cerdán et al, 2002 4-Ethylguaiacol Smoky, spicy, floral, cured bacon-like Lebrun, 1991;Cerdán et al, 2002 Furfural Almond-like, grainy, contributes to "hotness" of spirits Cerdán et al, 2002;Lee et al, 2000;Singleton, 1995 5-Hydroxymethyl furfural Odourless Cerdán et al, 2002 Methylfurfural Toasted almond Lebrun, 1991 Phenolic acids Contributes to overall bitterness and astringency Jindra & Gallander, 1987 Phenolics: o-Cresol, p-cresol Reduce the harshness of brandy, improve the taste of brandy products, interact with flavour constituents and as such have a significant effect on the perception of food and beverage flavour Singleton, 1974;Suomalainen et al, 1974;Venkataramu et al, 1983;Francis et al, 1992;Jung et al, 2000 of different extraction conditions, mediums and suppliers of oak chips on chemical and sensory profiles (Van Jaarsveld et al, 2009a). The second paper discussed the influence of oak type on the sensory and chemical profiles of fortified extracts and unmatured and matured pot-still brandy (Van Jaarsveld et al, 2009b), while the third focused on the impact of toasting on quality and chemical profiles (Van Jaarsveld et al, 2009c).…”

Section: Introductionmentioning

confidence: 99%

Rapid Induction of Ageing Character in Brandy Products. Ageing and General Overview

2016

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Ageing is one of the most important and most costly factors determining the quality of distilled beverages. As part of a broader study that investigated techniques for the rapid induction of a desirable ageing character in brandy products, the effect of maturation for eight months at room temperature and below 0°C in glass bottles, and the relationship/correlation between treatment, chemical composition or wood-derived congener concentrations and pot-still brandy sensory quality, are reported on. Extracts representing different oak types (American or French), levels of toasting, suppliers (i.e. cooper or commercial), types of medium (ethanol or water), concentration types (open or reduced pressure) and concentration levels (by 45, 65 or 85%) were added to pot-still spirit and stored for eight months in glass containers. Matured and unmatured (control) pot-still brandy samples were analysed for wood-derived compounds by means of HPLC and GC. The different treatments brought about chemical changes with a noticeable impact on the acceptability of oak extracts and the overall quality of pot-still brandies. Through application and selection of the correct oak type and treatment combinations, it therefore was possible to rapidly produce good quality brandies without the use of expensive oak barrels. Maturation in glass bottles had a lesser impact on further improvement of the final product, not the same as the reported improvement from ageing in wooden barrels. The production of good quality brandies and the rapid induction of the ageing character through certain treatment combinations, with little need for further maturation, therefore was achieved in glass. The complexity of brandies aged in glass rather than wooden barrels might be different, since ageing in wooden barrels brings about all the characteristics, complexities and flavours that characteristically evolve over time under the more oxidative conditions in wooden barrels. Future research should focus on a combination of both technologies, using certain oak treatment combinations together with traditional barrel maturation for the improvement and rapid induction of the ageing character in brandy products. ** The Fruit, Vine and Wine Institute of the Agricultural Research Council INTRODUCTION A wide range of distilled beverages, including whisky and brandy, continue to be matured in oak barrels. During maturation, a range of physical and chemical interactions take place between the barrel, the surrounding atmosphere and the maturing spirit. These transform the colour, flavour and composition of the beverage. The effects of, and the time required for, maturation are highly variable, and are influenced by a wide range of factors, such as the distillate, the size, origin of the wood and treatment of the barrel, and the maturation environment. The change in flavour of the maturing spirits is due to changes in the composition and concentration of compounds influencing the taste and aroma, and may be caused by (1) direct extraction of wood compounds, (2) decomposit...