La fermentation malolactique et son importance dans les vins rouges de table australiens

Pendant des siècles on a observé qu'après la fin de leur fermentation alcoolique, certains vins rouges de table se troublent en libérant de petites bulles de gaz. Ce curieux phénomène ne paraît pas nuire à la qualité mais souvent, au contraire, semble l'améliorer. Il coïncide généralement avec la montée de la sève dans la vigne et on peut penser que, d'une certaine manière, ces deux phénomènes sont liés ; ils sont cependant le résultat de l'élévation de la température. Un Allemand, KULISH, en 1889, semble avoir le premier établi la nature biologique du phénomène, bien que PASTEUR l'ait laissé entrevoir auparavant. Depuis, la fermentation malolactique, comme on l'appelle, a été étudiée dans les diverses parties du monde. Nous connaissons maintenant en grande partie cette fermentation et cet article se propose de résumer brièvement nos connaissances, d'en indiquer les derniers développements, tout particulièrement en ce qui concerne les vins australiens

Consumer acceptance of synthetic corks

Problems with corks are a major issue in the wine industry. The key problem has been the lack of consumer acceptance of alternative closures. This research used an interview and survey approach with 200 wine shoppers in Australia to determine: 1) consumer perceptions of cork problems; 2) acceptance of a synthetic cork with no information provided; and 3) acceptance of a synthetic cork after providing information concerning cork problems and solutions. Consumers who purchased more than one bottle of wine per week had the most problems with corks, but 75% of all consumers interviewed had experienced some problems in the last 12 months. The provision of information was key in gaining consumer acceptance of the synthetic corks. Measures of which attributes of the synthetic corks attracted consumers is also provided along with recommendations for introducing these closures into the marketplace.Warwick Murray and Lawrence S. Lockshi

In situ measurement of white wine absorbance in clear and in coloured bottles using a modified laboratory spectrophotometer

In situ absorbance of visible light by white wine in bottles was determined with a modified spectrophotometer. A linear correlation was obtained between absorbance at 420 nm A₄₂₀ measured in a cuvette (10 mm pathlength) and absorbance of that same wine measured in a 750 mL Flint bottle (colourless transparent glass). In addition, 5 types of coloured bottles, Emerald Green, Classic Green, French Green, Georgia Green and Cobalt Blue, also yielded strong correlations. A₄₂₀ of white wine in bottles of Antique Green or Amber glass could not be measured directly due to a strong absorbance of that wavelength by the glass. However, a strong correlation was established between measurement of A₄₂₀ (cuvette) and A₅₄₀ for white wine in Antique Green bottles and between A₄₂₀ (cuvette) and either A₅₄₀ or A₆₀₀ for white wine in Amber bottles. The method employed a standard UV-Visible spectrophotometer with an inexpensive modified sample port, and proved applicable to bottles with diameters ranging from 62 mm (375 mL capacity half bottles) up to 81 mm (750 mL capacity Burgundy bottles). In situ absorbance measurements plus subsequent chemical analysis and sensory assessment of a Chardonnay wine in Antique Green bottles showed that the method provided an estimate of oxidation in this white wine. Wine absorbance spectra over the full visible range were obtained in the Flint bottle. Measurements of the absorbance of visible light by the glass of empty bottles could also be obtained and used as a form of quality control for glass bottle manufacture.George K. Skouroumounis, Mariola Kwiatkowski, Mark A. Sefton, Richard Gawel and Elizabeth J. Water