Winetech Technical Yearbook 2022

MAY

48 A RECENT STUDY INVESTIGATED VARIOUS SPARGING PARAMETERS AND ASSESSED THE EFFECTIVITY, WHILE MONITORING CERTAIN WINE CONSTITUENTS. BY CARIEN COETZEE, JAMES WALLS, STEVEN SUTTON & WESSEL DU TOIT I WINETECH TECHNICAL YEARBOOK 2022 INTRODUCTION The presence of dissolved oxygen in wine can lead to oxidation reactions with undesirable effects on the wine composition and quality. Wine producers often remove dissolved oxygen from wine using inert gas sparging techniques. Although sparging operations are common in the wine industry, factors affecting the efficacy of sparging regimes have been rarely investigated. Researchers from the South African Grape and Wine Research Institute, Stellenbosch University (James Walls, Steven Sutton, Dr Carien Coetzee and Prof Wessel du Toit) conducted a Winetech-funded study to investigate the effect of certain variables, such as inert gas flow rate, gas composition, duration of sparg ing, number of sparging cycles, wine temperature and the utilisation of a diffusion stone (bubble size), while also assessing the influence of the different sparging regimes on the wine’s composition. The findings of this study were published in an MScAgric thesis in 2020 titled, Effect of oxygen management on white wine composition by James Walls. 1 In Part 1 of this two-part article, the effect of inert gas flow rate, wine temperature and gas composition were summarised (experiments 1 and 2). In Part 2, the main effects of bubble size, repetitive sparging and extended sparging duration will be reported. MATERIALS AND METHODS Sauvignon blanc (Stellenbosch) and Chenin blanc (Breede River Valley) wines were exposed to several sparging regimes. The wines were made according to the respective wineries’ standard practices and were Factors affecting sparging efficiency (PART 2)

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