Comparison of altyernative systems for the ageing of wine brandvy. Oxigenation and wood shape effect.

during the first year of ageing, the dissolved oxygen, dry extract, total polyphenol index, low molecular weight compounds, colour parameters and sensory properties of wine brandies were analysed with regard to the kind of ageing system: 650-l wooden barrels (traditional system) and 40-l stainless-steel tanks with wood tablets, with and without oxygenation (alternative systems). the barrels and wood pieces were manufactured from portuguese chestnut wood (castanea sativa mill.) with heavy toasting level. the quantity of tablets was calculated in order to reproduce the surface/volume ratio of a 650-l barrel. the oxygenation was made by the application of air with a specific device in the middle height of the tanks, after 60, 90, 120, 180 and 360 days of ageing. in the experimental conditions, the results obtained demonstrated that the chemical composition and the colour evolution of the wine aged brandies are closely dependent on the ageing system. the oxygen effect on the total polyphenol index and on the low molecular weight phenolic compounds found in the brandies aged in traditional and alternative systems is quite different. this aspect is of great importance since it is strongly related with the chemical changes that occur during the ageing process and determine the quality of the brandies. contrary to what have been observed in the ageing of red wines, the oxygen consumption in the brandies aged in wooden barrels did not induced colour stabilization, suggesting that the chemical mechanisms and the compounds responsible for the colour changes of the brandy should be different from those identified in red wine.