Efficiency of alternative chemical and physical treatments in reducing Brettanomyces Bruxellensis from oak wood

Prefermentation steps of white winemaking are very important for controlling the stability and the sensory attributes of wines. Usually musts are clarified by cold settling to prevent the start of the fermentation, before racking big lees and thus limiting the appearance of vegetable or reduction off flavour while favouring an aromatic expression with low turbidity. Besides, to reach the protein stability, some white wines further require a bentonite fining, sometimes associated with negative effects on the sensory quality. This study aims to know the impact of musts heating after pressing on a Chardonnay wine in northern conditions by comparison with a classic cold racking of the must.

Fungal bunch rots of grapes cause major losses to grape yield worldwide, yet the impact these moulds have on grape and wine quality is not well characterised. We sought to investigate the formation of unwanted volatile compounds of fungal origin in both synthetic grape juice culture media and in inoculated grape berries. Botrytis cinerea, Aspergillus niger, Aspergillus carbonarius, or Pencillium expansum were grown in synthetic grape juice medium and the culture homogenates analysed 4 and 7 days post inoculation. HS-SPME-GC-MS analysis of the culture homogenates 4 days post inoculation demonstrated that each of the fungi examined produced varying quantities of the mushroom or fungus-like aroma compounds, 1-Octen-3-ol, 1-Octen-3-one and 3-Octanone with A. carbonarius producing up to ten times the amounts of all three metabolites per mg of dry mycelium.

Those previous years, pesticides are often brought to the forefront by media. Questions arose about their toxicity for growers and consumers. Even if a downward trend is underway, the use of pesticides is required to ensure steady quality and quantity of harvests. A large number of active ingredients are authorized but regarding viticulture, mainly insecticides and fungicides are applied, to control pests and diseases and to increase crop yield. Some phytosanitary products, principally fungicides, applied close to the harvest date may frequently be detected in wines.

The genetic material preservation is a priority issue in winemaking research. The recovery of minority grape varieties can control the genetic erosion, contributing also to preserve wine typical characteristics. In D.O.Ca. Rioja (Spain) the number of grown white varieties has been very limited, representing Viura the 91% of the cultivated white grape area in 2005, while the others, Garnacha Blanca and Malvasía riojana, hardly were grown. For this reason, a recovery and characterization study of plant material was carried out in this region. In 2008, the results obtained allowed the authorization of three minority white varieties: Tempranillo Blanco, Maturana Blanca and Turruntés.

Beihong and Beimei are two wine cultivars from ‘Muscat Hamberg’ (V. vinifera L.) and wild V. amurensis Rupr., which were released in China in 2008. Here，two enology practices were reported. Firstly, the impact of different yeasts including D254, GRE, K1, D21 and BDX on dry wine quality of Beihong and Beimei was investigated. For Beihong, among wines fermented by all yeasts, residual sugar content was the lowest, total anthocyanin and resveratrol contents were the highest in the wine by D254. However, the wine by D254 had lower titrable acid than those by the other yeasts except BDX.