Developing techniques to rapidly induce the needed ageing character in brandy products

Project Number
WW 09-05

Project title
Developing techniques to rapidly induce the needed ageing character in brandy products

Project leader
Van Jaarsveld, F P

Team members
Bosman, D

Project description
The aim of this project is to develop techniques to accelerate the ageing of brandy, by means of the addition of oak extracts and or treatments of spirits and extract mixtures. Thirty extracts were prepared from different types of wood, obtained from different companies. The extracts were added to distillates (70% alcohol) in an attempt to rapidly induce an aged character in brandies. These rapidly aged brandies were matured further at 20°C in sealed glass containers, evaluated after eight and sixteen months and compared to the initial product (no extract added). The treatments that scored the highest and lowest were selected for chemical determination of the aroma impact components at the University of Stellenbosch.

Results from this study showed that the composition of the extract added to the unaged spirits, is of critical importance to the quality of the product after ageing. GC-MS analysis of aroma impact components is a good indicator for judging the quality of the product objectively. The method used for making the extracts had a significant effect on the chemical composition and quality of the product. Storage temperature also had a minor effect on the concentrations of the aroma impact components.

Generally, American oak, toasted at 220°C to 230°C, gave the highest quality products. This will be verified with the new extracts. Water extracts, as part of the ongoing study, will be compared to a few ethanol extracts (Table 3). The preparation of the new extracts, however, is much more elaborate than that of the previous extracts, including distillation, fortification and concentration. Very little work has been done to determine the optimum levels to which a sample can be concentrated in order to give the highest concentration of the important aroma impact components and highest sensory score. It is clear from discussions with the relevant people involved with the preparation of extracts, that this information would be rather valuable. Concentration of the samples will be done open (higher boiling point) and under vacuum (lower boiling point), thus taking into consideration the effect that temperature might have on the chemical components.

Presentation(s)
Van Jaarsveld, F P. 2001. Examining trends and developments in South African production with specific reference to research conducted at the ARC Infruitec-Nietvoorbij. Presentation at the The Beverage Industry Symposium. 30 July – 1 August, Cape Town, South Africa.

Van Jaarsveld, F P. 2002. Invloed van mostroebelheid en gismoerinhoud op rabatwyn- en potketelbrandewyn kwaliteit. Paper presented at the 26th National Congress of the South African Society for Enology and Viticulture. 13-15 November, Somerset West, South Africa.

Article
Van Jaarsveld, F P, Blom, M, Hattingh, S, Marais, J. 2005. Effect of juice turbidity and yeast lees content on brandy base wine and unmatured pot-still brandy quality, South African Journal of Enology and Viticulture, v. 26 (2) (p. 116-130)
Article.pdf

Van Jaarsveld, F P, Hattingh, S, Minnaar, P, Blom, M. 2009. Rapid induction of ageing character in brandy products. Part 1. Effects of extraction media and preparation conditions, South African Journal of Enology and Viticulture, v. 30 (1) (p. 1-15)
Article.pdf

Van Jaarsveld, F P, Hattingh, S, Minnaar, P P. 2009. Rapid induction of ageing character in brandy products. Part 2. Influence of type of oak, South African Journal of Enology and Viticulture, v. 30 (1) (p. 16-23)
Article.pdf

Van Jaarsveld, F P, Hattingh, S, Minnaar, P P. 2009. Rapid induction of ageing character in brandy products. Part 3. Influence of toasting, South African Journal of Enology and Viticulture, v. 30 (1) (p. 24-37)
Article.pdf

FinalReport.pdf

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