Distillation and Aging

Flavour of Spirit Drinks Raw Materials, Fermentation, Distillation, and Ageing... 

The following review focuses on the composition of flavour compounds in spirit drinks, their origin, and their sensory attributes like odour quality and threshold value. Important information on flavour-related aspects of technology, like distillation and ageing, as well as the main categories and brands of spirits to be found on the national and international markets are summarised. Finally, aspects of sustainability in the production of distilled spirits are discussed. 

Distilled spirits are produced from different fermented plant materials grown all over the world. The most important criteria of quality and authenticity of each type of distilled spirits are the typical flavour composition originating from the raw material and/or the special techniques of fermentation, distillation, and ageing. In the following sections, specific flavour compounds and flavour-related technologies as well as peculiarities of the most important categories of distilled spirits are summarised. 

The overall chemical composition of brandy is derived from four general sources the fruit, alcoholic fermentation, distillation, and aging in wood. The scope of this discussion is limited to chemical aspects of the components of wine and their behavior during distillation. 

N. Christoph C. Bauer-Christoph, Flavour of Spirit Drinks Raw Materials, Fermentation, Distillation, and Ageing. In Flavours and Fragrances Chemistry, Bioprocessing and Sustainability, R. G. Berger, Ed. Springer-Verlag Berlin, 2007 pp 219-239. 

Whiskeys Grains brewed with water to form a beer of 5%-10% alcohol. Beer is distilled and aged in new or used charred oak barrels for two to eight years before blending. 40-50... 

Asphalt Asphalt is a natural occurring mineral or as the residue from the distillation of asphaltic petroleum. It is less brittle and has better resistance to sunlight and temperature changes than coal tar enamel. Its water resistance is good but less than for coal tar enamel. It is not resistant to solvents or oils. It may crack at low temperatures and age at elevated ones. Like coal tar enamels, it is primarily black in color and difficult to overcoat with other materials. Its main use is for the in-situ coating of roofs or aboveground steel structures. 

Hayek et al. (1990) reported the identification of 14 samples of birch bark tar of Chalcolithic to Early Iron Age date from sites in Austria and Denmark. In this study, authentic tars from bark samples of a number of different species (e.g., birch, oak, alder, hazel, elm and so on) were produced under laboratory conditions (using Kugelrohr distillation) and compared with the aged samples... 

The composition of crude oil may vary with the location and age of an oil field, and may even be depth dependent within an individual well or reservoir. Crudes are commonly classified according to their respective distillation residue, which reflects the relative contents of three basic hydrocarbon structural types paraffins, naphthenes, and aromatics. About 85% of all crude oils can be classified as either asphalt based, paraffin based, or mixed based. Asphalt-based crudes contain little paraffin wax and an asphaltic residue (predominantly condensed aromatics). Sulfur, oxygen, and nitrogen contents are often relatively higher in asphalt-based crude in comparison with paraffin-based crudes, which contain little to no asphaltic materials. Mixed-based crude contains considerable amounts of both wax and asphalt. Representative crude oils and their respective composition in respect to paraffins, naphthenes, and aromatics are shown in Figure 4.1. 

Surface tension measurements. Solutions of the betaines were prepared with quartz-condensed, distilled water, specific conductance, 1.1 X 10" mho cm" at 25°C. All surface tension measurements were made by Wilhelmy vertical plate technique. Solutions to be tested were immersed in a constant-temperature bath at the desired temperature 0.02°C and aged for at least 0.5 h before measurements were made. The pH of all solutions was > 5.0 (usually, in the range 5.5-5.9), where surface properties show no change with pH. 

In any event, it is also recognized that increased energy costs will dictate the use of membrane processes over competitive high energy processes such as distillation and evaporation. In this regard, we are indebted to Loeb and Sourirajan for a timely invention for the energy-scarce age we are now entering. 

In the United States about 95% of the brandy comes from California. The first brandy was made in 1837 though it was not produced in quantity until 1867. All California brandy must be made from grapes grown and distilled in the state and aged a minimum of two years in oak barrels. 

Cognac is spirit distilled from wine so that it retains the various volatile substances largely constituting the bouquet of the wine, and stored and aged for a longer or shorter time in wooden (oak) casks by dissolution of extractive tannin substances from the wood it assumes the well-known amber-yellow colour. 

An analysis of the extensive literature data and the data of the authors of this book [1640, 1642, 1655] permits a conclusion that the variations in the physicochemical characteristics of Al(OR)3 are caused by the existence of different types of aggregates and the possibility oftheir mutual transformations. The molecular composition depends on the conditions in the course of sample preparation — temperature, nature ofthe solvent applied, and the age ofthe sample. An important role is also played by the presence in the samples of microamounts of oxocomplexes, which are always formed on sublimation, distillation, and any other thermal treatments. 

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