Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The total sale of brandy for 2007 in South Africa was R 7 300 000 000 and local statistics indicate that brandy is by far the most purchased spirit beverage. Sales of brandy even outweigh the total sales for whisky and the forecast for the estimated sales of brandy in the next five years is said to increase by 25%. It is therefore crucial to investigate those factors that influence the production of brandy as better understanding and control of these processes leads to the production of a brandy that is consistent and of premium quality. Many factors influence the final outcome of distillates. Of these factors, the distillation technique, the apparatus used for the purpose of distillation together with the low wine is of utmost importance as they influence the sensory profile and the chemical composition of the distillate. The effect of different variations of pot still designs on the chemical composition and the sensory profile of the resultant distillate was investigated. Five different Pot still variations were used and varied with regards to the design of their pot still head and swans neck apparatus. Two low wines were used for the purpose of distillations and were both from 2007 vintage. GCFID was used to identify the volatile compounds found in the distillates and together with Quantitative Descriptive Analysis (QDA) a profile of the distillates was produced which was used to differentiate between the different pot still variations and their effect on the final product. The data generated from the QDA sessions was subjected to Principal Component Analysis (PCA) and together with the chemical analysis a correlation between certain compounds and sensory attributes were found in the distillates. Distillate samples were also subjected to a sensory style classification system and were classified accordingly. The chemical composition of the two low wines prior to distillations differed significantly from each other with low wine one containing a larger amount of total esters and carbonyl compounds whilst low wine two contained a larger amount of total higher alcohols and acids. The distillates of low wine one also contained over all larger amounts of total esters and in the case of the distillates of low wine two, they contained larger amounts of higher alcohols and acids than low wine one. Variation one was based on the Alambic Charentais method of pot still design and it was found that only variation one influenced the chemical composition and the sensory profile of the distillates. This variation produced a distillate with a lower amount of total esters and more specifically ethyl acetate as well containing a lower intensity of the fruit and sweet associated caramel aromas and flavours. The esters, ethyl acetate and the ethyl esters of the long chained fatty acids were found to correlate with the sensory attributes known as fruit associated aroma, soapy aroma, and spicy aroma and therefore indicated that these compounds are responsible for these attributes. There were no correlations found between the chemical compounds, sensory attributes and sensory style classifications in the distillates of both low wine one and two. It was shown that the addition of certain esters, carbonyl compounds, higher alcohols and acids in specific ratios could alter the sensory classification of the distillates. Therefore the chemical composition and the sensory characteristics of distillates are largely dependent on the chemical composition of the low wine prior to distillation rather than the pot still design. Therefore, with further research it could be possible to predict the outcome of the chemical composition of the distillates by analyzing the chemical compounds found in the low wine prior to distillation. / AFRIKAANSE OPSOMMING: Die totale verkope aan brandewyn vir 2007 in Suid Afrika beloop R7 300 000 000 en statistiek wys dat brandewyn by verre die mees gesogte spiritus drank is. Verkope van brandewyn is selfs meer as die verkope van whisky en die voorspelling is dat die verkope van brandewyn met 25% gaan vermeerder in die volgende vyf jaar. Dit is dus belangrik om die faktore te ondersoek wat die produksie van brandewyn beïnvloed om sodoende die verstokingsproses te verstaan en te kontroleer om ‘n konsekwente kwaliteitsproduk op die mark te plaas. Baie faktore beïnvloed die finale produk. Faktore soos die distillasie tegnieke, die apperate wat gebruik word vir distillasie tesame met die rabatspiritus is van die uiterste belang aangesien dit die sensoriese profiel en die chemiese samestelling van die distillaat beïnvloed. Die effek van die verskillende variasies van potketelhelms op die chemiese samestelling van die distillate word ondersoek. Vyf verskillende helms met variasies in die swaannek ontwerp was gebruik. Twee verskillende rabatspiritus, van die 2007 oesjaar, was gebruik vir distillasie. GC-FID was gebruik om die vlugtige komponente van die distillate mee vas te stel. Kwantitatiewe Beskrywende Analise (QDA) is gebruik om ‘n profiel van die distillate op te stel wat weer gebruik is om te differensieer tussen die verskillende potketelhelm variasies en hulle effek op die finale produk. Die data wat deur die QDA sessies gegenereer was, is in die Vernaamste Komponent Analise (PCA) ingevoer en tesame met die chemiese analise is ‘n korrelasie tussen sekere komponente en die sensoriese analise van die distillate gevind. Distillaat monsters was ook aan sensoriese styl van klassifikasie onderwerp en is as volg daarvan geklassifiseer. Die chemiese samestelling van die twee rabatspiritus voor finale distillasie het betekenisvol van mekaar verskil ten opsigte daarvan dat die eerste rabatspiritus het hoë konsentrasies esters en karboniel verbindings gehad terwyl die tweede rabatspiritus meer hoë konsentrasies van sure en hoër alkohole gehad het. Die distillaat van die eerste rabatspiritus het ook hoë konsentrasies esters en karboniel verbindings gehad terwyl die distillaat van die tweede rabatspiritus weer hoë konsentrasies van sure en hoër alkohole gehad het. Variasie een is gebaseer op die Alambic Charentais van potketel ontwerp en daar is ook gevind dat hierdie variasie die enigste een was wat die chemiese samestelling en die sensoriese profiel van die distillate beïnvloed het. Hierdie variasie het ‘n distillaat geproduseer wat lae konsentrasies van totale esters, veral etielasetaat, sowel as laer intensiteit van vrugtige en soet geassosieerde karamel aromas en geure. Die esters, etielasetaat en etiel esters van die lang ketting vetsure, is gevind dat dit goed korreleer met die sensoriese eienskappe wat geassosieer word met vrugtige aromas, spesery-agtige aromas en seperige aromas. Daar is geen korrelasie gevind tussen die chemiese verbindings, sensoriese eienskappe en sensoriese styl van klassifikasie van distillate een en twee nie. Dit was ook bewys dat byvoeging van esters, karboniel verbindings, sure en hoër alkohole, in spesifieke verhoudings, die sensoriese eienskappe kan verander. Dus is die chemiese samestelling en sensoriese eienskappe van die distillate grootliks afhanklik van die chemiese samestelling van die rabatspiritus, voor die tweede distillasie, as wat dit afhanklik is van die potketelhelm ontwerp. Gevolglik, met verdere v navorsing, is dit moontlik om die uitkoms van die chemiese samestelling van die distillaat te voorspel deur die analise van die chemiese verbindings van die rabatspiritus te ontleed.

O presente estudo teve por objetivo determinar a composição química de aguardentes obtidas por redestilação, a partir de diferentes concentrações iniciais do flegma (30, 40 e 50% v/v), visando definir um processo que resulte em uma melhor qualidade química e um melhor rendimento operacional. Determinou-se a composição química das aguardentes produzidas mediante análises de teor alcoólico, componentes voláteis (aldeídos, ésteres, metanol, álcoois superiores, ácido acético e furfural) e contaminantes (álcoois n-butílico e sec-butílico, cobre e carbamato de etila). Com exceção dos álcoois superiores, todos os destilados alcoólicos simples (DAS) apresentaram composição química de compostos voláteis e de contaminantes dentro das especificações legais. Quanto aos álcoois superiores, os DAS provenientes dos flegmas com 30% e 40% de etanol apresentaram-se ligeiramente acima do máximo permitido pela legislação (360 mg/100mL de álcool anidro). O DAS proveniente do flegma com 50% de etanol apresentou concentração de álcoois superiores dentro do limite estabelecido pela legislação. O álcool isoamílico correspondeu a 70% do teor de álcoois superiores dos destilados. Os resultados mostraram que o teor alcoólico do flegma (30, 40 e 50% em etanol) não influenciou a qualidade química dos destilados alcoólicos simples destinados a elaboração da aguardente de cana. Nas condições da presente pesquisa, a redestilação do flegma a 50% de etanol foi a que proporcionou o maior rendimento operacional na aguardente produzida. / This study aimed to determine chemical composition of spirits obtained by redistillation from different initial concentrations of low wines (30, 40 and 50% alcohol by volume), defining a process resulting in a better chemical quality and operational efficiency than the initial product. The chemical composition of the spirits produced were determined by alcoholic analysis, volatiles (aldehydes, esters, methanol, higher alcohols, acetic acid and furfural acid) and contaminants (alcohols n-butyl and secbutyl, copper and ethyl carbamate). With the exception of higher alcohols, all simple alcoholic distillates (SAD) had a chemical composition of volatiles and contaminants within legal specifications. The higher alcohols, those from low wines with 30% and 40% etanol concentration, exhibited slightly above the maximum allowed by brazilian law (360mg / 100mL anhydrous ethanol). The SAD from the low wines with 50% ethanol showed a higher alcohols concentration within the limits established by law. The isoamyl alcohol matched to 70% of distillated higher alcohol content. The results showed that the alcohol content of low wines (30, 40 and 50% ethanol) did not influence the chemical quality of simple alcoholic distillates for the preparation of sugar cane spirit. Under the conditions of this study, redistillation of low wines 50% ethanol was the one that provided the highest operating income in the produced spirit.

O presente estudo teve por objetivo determinar a composição química de aguardentes obtidas por redestilação, a partir de diferentes concentrações iniciais do flegma (30, 40 e 50% v/v), visando definir um processo que resulte em uma melhor qualidade química e um melhor rendimento operacional. Determinou-se a composição química das aguardentes produzidas mediante análises de teor alcoólico, componentes voláteis (aldeídos, ésteres, metanol, álcoois superiores, ácido acético e furfural) e contaminantes (álcoois n-butílico e sec-butílico, cobre e carbamato de etila). Com exceção dos álcoois superiores, todos os destilados alcoólicos simples (DAS) apresentaram composição química de compostos voláteis e de contaminantes dentro das especificações legais. Quanto aos álcoois superiores, os DAS provenientes dos flegmas com 30% e 40% de etanol apresentaram-se ligeiramente acima do máximo permitido pela legislação (360 mg/100mL de álcool anidro). O DAS proveniente do flegma com 50% de etanol apresentou concentração de álcoois superiores dentro do limite estabelecido pela legislação. O álcool isoamílico correspondeu a 70% do teor de álcoois superiores dos destilados. Os resultados mostraram que o teor alcoólico do flegma (30, 40 e 50% em etanol) não influenciou a qualidade química dos destilados alcoólicos simples destinados a elaboração da aguardente de cana. Nas condições da presente pesquisa, a redestilação do flegma a 50% de etanol foi a que proporcionou o maior rendimento operacional na aguardente produzida. / This study aimed to determine chemical composition of spirits obtained by redistillation from different initial concentrations of low wines (30, 40 and 50% alcohol by volume), defining a process resulting in a better chemical quality and operational efficiency than the initial product. The chemical composition of the spirits produced were determined by alcoholic analysis, volatiles (aldehydes, esters, methanol, higher alcohols, acetic acid and furfural acid) and contaminants (alcohols n-butyl and secbutyl, copper and ethyl carbamate). With the exception of higher alcohols, all simple alcoholic distillates (SAD) had a chemical composition of volatiles and contaminants within legal specifications. The higher alcohols, those from low wines with 30% and 40% etanol concentration, exhibited slightly above the maximum allowed by brazilian law (360mg / 100mL anhydrous ethanol). The SAD from the low wines with 50% ethanol showed a higher alcohols concentration within the limits established by law. The isoamyl alcohol matched to 70% of distillated higher alcohol content. The results showed that the alcohol content of low wines (30, 40 and 50% ethanol) did not influence the chemical quality of simple alcoholic distillates for the preparation of sugar cane spirit. Under the conditions of this study, redistillation of low wines 50% ethanol was the one that provided the highest operating income in the produced spirit.