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

As part of a broader study that investigated techniques for the rapid induction of the needed ageing character in brandyproducts, the effect of oak type on quality and chemical composition of oak wood extracts and matured and unmatured potstillbrandy, 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) unmaturedpot-still brandy and stored for eight months in glass containers (Schott bottles) at room temperature, or in the case ofcontrols, below 0°C. Matured and unmatured (control) pot-still brandy samples were analysed for wood-derived congenersby means of HPLC and GC. Although French oak initially yielded better quality products, these effects lost prominenceand, after eight months maturation, yielded similar sensory quality to American oak. French oak samples had higherconcentrations 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 higherproportions of the more sensorially potent cis-form of lactone than its trans-isomer

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

As part of a broader study that investigated techniques for the rapid induction of the needed ageing character inbrandy products, the effect of oak wood toasting on quality and chemical composition of oak wood extracts andmatured and unmatured pot-still brandy, is reported on. Extracts, prepared from oak chips supplied by a SouthAfrican 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 eightmonths in glass containers (Schott bottles) at room temperature, or in the case of controls, below 0°C. Matured andunmatured (control) pot-still brandy samples were analysed for wood-derived congeners by means of HPLC andGC. Toasted, as opposed to untoasted oak, gave acceptable extracts, the best overall quality pot-still brandies andgenerally higher concentrations of volatile (GC-determined) and less volatile (HPLC-determined) wood-derivedcongeners. Toasting provoked an important separation as indicated by discriminant analysis

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

The purpose of this study was to investigate the use of different wood types and treatments, and extraction mediato induce rapid ageing of brandy. Extracts were prepared from American and French oak, specially preparedand supplied by a cooper, and from commercially obtained oak; both representative of different toasting levels,including untoasted, light, medium and heavy toasted. To extract the wood components, wood chips in either 55%(v/v) neutral wine spirits or water media were boiled under reflux. Distillation was followed by either open (higherboiling temperature) or closed (vacuum or reduced pressure – lower boiling temperature) concentration of thedecanted solvent by 45, 65 and 85% (v/v). The concentrated extracts were fortified. Screened extracts were addedto unmatured pot-still brandy and aged for eight months at room temperature in glass containers. Controls werestored below 0°C. Matured and unmatured (control) pot-still brandy samples were analyzed for wood-derivedcongeners by means of HPLC and GC. This article focuses on the effects of the extraction media, and on level andmethod of concentration (open and reduced pressure) on sensory quality and chemical composition. The treatmentsthat gave acceptable extracts, and the best overall quality pot-still brandy were those that entailed (1) using ethanolinstead of water as extraction medium, and (2) levels of concentration above 45% (v/v). Open and reduced-pressureconcentrations showed little difference in the quality of the products yielded. Treatments yielding the most acceptableextracts and best overall quality pot-still brandy generally also contained higher concentrations of volatile andless volatile wood-derived congeners. Multivariate data analysis was conducted on the pot-still brandy samplesrepresenting the different treatments. Discriminate analysis provided better separation of samples than principalcomponent analysis

Die spore van Raka: oor herskrywing en kanonisering (Deel 1)

Every literary system possesses a canon with the classical canon as the most stable and simultaneously the one with the most restrictive access. Writers and texts can only maintain their position within the canon through continuous rewriting: critical rewriting by literary critics (as shapers of taste and gate-keepers) and creative rewriting by fellow writers. In this study the critical rewriting (and rerealisation) of one of the most acclaimed and seminal texts in Afrikaans literature, Raka (1941), by N. P. van Wyk Louw is scrutinized. Since its publication this verse epic has been firmly entrenched in the classical Afrikaans literary canon and its continuous rewriting / rerealisation can act as a case study of how a literary “masterpiece” is dependent on institutional relationships, relevant characteristics and strategic position-taking within a literary field in order to retain this status. Against the backdrop of a theoretical framework set out in part one of this study, the specifics of Raka’s rewriting / rerealisation is discussed in the second part

Rapid induction of ageing character in brandy products : ageing and general overview

CITATION: Van Jaarsveld, F. P. & Hattingh, S. M. 2012. Rapid induction of ageing character in brandy products : ageing and general overview. South African Journal of Enology and Viticulture, 33(2):225-252, doi:10.21548/33-2-1122.The original publication is available at http://www.journals.ac.za/index.php/sajevAgeing 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.http://www.journals.ac.za/index.php/sajev/article/view/1122Publisher's versio

African leafy vegetables in South Africa

In this article the term ‘African leafy vegetables’ was adopted to refer to the collective of plant species which are used as leafy vegetables and which are referred to as morogo or imifino by African people in South Africa. Function is central in this indigenous concept, which is subject to spatial and temporal variability in terms of plant species that are included as a result of diversity in ecology, culinary repertoire and change over time. As a result, the concept embraces indigenous, indigenised and recently introduced leafy vegetable species but this article is concerned mainly with the indigenous and indigenised species. In South Africa, the collection of these two types of leafy vegetables from the wild, or from cultivated fields where some of them grow as weeds, has a long history that has been intimately linked to women and their traditional livelihood tasks. Among poor people in remote rural areas the use of these types of leafy vegetables is still common but nationwide there is evidence of decline, particularly in urban areas. Cultivation of indigenous or indigenised leafy vegetables is restricted to a narrow group of primarily indigenised species in South Africa. Seven groups of indigenous or indigenised African leafy vegetables that are important in South Africa were given special attention and their local nomenclature, ecology, use and cultivation are discussed.Keywords: African leafy vegetables, morogo, imifino, history, ecology, gender, collection, cultivation, use, processing, storag

African leafy vegetables in South Africa

In this article the term ‘African leafy vegetables’ was adopted to refer to the collective of plant species which are used as leafy vegetables and which are referred to as morogo or imifino by African people in South Africa. Function is central in this indigenous concept, which is subject to spatial and temporal variability in terms of plant species that are included as a result of diversity in ecology, culinary repertoire and change over time. As a result, the concept embraces indigenous, indigenised and recently introduced leafy vegetable species but this article is concerned mainly with the indigenous and indigenisedspecies. In South Africa, the collection of these two types of leafy vegetables from the wild, or from cultivated fields where some of them grow as weeds, has a long history that has been intimately linked to women and their traditional livelihood tasks. Among poor people in remote rural areas the use of these types of leafy vegetables is still common but nationwide there is evidence of decline, particularly in urban areas. Cultivation of indigenous or indigenised leafy vegetables is restricted to a narrow group of primarily indigenised species in South Africa. Seven groups of indigenous or indigenised African leafyvegetables that are important in South Africa were given special attention and their local nomenclature, ecology, use and cultivation are discussed

Gas Chromatography Results Interpretation: Absolute Amounts Versus Relative Percentages

Geneeskunde en GesondheidswetenskappeChemiese PatologiePlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

Effect of juice turbidity and yeast lees content on brandy base wine and unmatured pot-still brandy quality

CITATION: Van Jaarsveld, F. P., et al. 2005. Effect of juice turbidity and yeast lees content on brandy base wine and unmatured pot-still brandy quality. South African Journal of Enology & Viticulture, 26(2):116-130, doi:10.21548/26-2-2126.The original publication is available at http://www.journals.ac.za/index.php/sajevThe aims of this project were to identify a suitable grape juice clarification technique for the attainment of the optimal brandy base wine turbidity, to determine the importance of chemical components (volatile components and long-chain fatty acids) in brandy base wine and unmatured pot-still brandy quality, and to study the effect of yeast lees content on quality. Although common industry practice is to use the grape cultivars Colombar(d) and Chenin blanc for the production of brandy base wine, the optimal conditions for Chenin blanc have been defined in this study. The juice clarification treatments applied included no settling, cold settling, whisk, large- and small-scale centrifugation and bentonite. Yeast strain 228 was compared with VIN13, large-scale (L) distillation was compared with small-scale (s) distillation, and the use of no enzyme was compared with the use of pectolytic enzyme. The data for four vintages were compiled and evaluated. Settling with or without pectolytic enzyme, bentonite, small-scale centrifugation and whisk treatments gave clearer Chenin blanc juice, higher concentrations of certain volatile components and long-chain fatty acids, and higher quality brandy base wine and unmatured pot-still brandy. No settling and large-scale centrifugation yielded the most turbid and lowest quality products. There is a definite relationship between treatments, turbidity, concentrations of esters, higher alcohols and acids, and overall brandy base wine and unmatured pot-still brandy quality. The use of yeast strain VIN13 (as opposed to strain 228), in conjunction with an increased yeast lees content of 1.5x that is normally found in brandy base wine, yielded the best quality unmatured pot-still brandy. Based on the results of this study, it is possible to recommend the best juice clarification method(s) for optimal turbidity as well as optimal levels of yeast lees addition, and to identify chemical compounds that positively relate to quality.http://www.journals.ac.za/index.php/sajev/article/view/2126Publisher's versio