Expertise documents

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The Fermentation of Fructose in Winemaking

Glucose and fructose are the main fermentable sugars in wine must. During alcoholic fermentation, yeast convert most of the glucose and fructose present into alcohol and CO2.  Saccharomyces cerevisiae is a glucophilic yeast, preferring glucose over fructose.  This issue of 'The WIne Expert' further explains this phenomenon.Wine Expert- The Fermentation of Fructose in winemaking 2013

SO2 production by wine yeast during alcoholic fermentation

This issue of 'The Wine Expert' will discuss how sulphur dioxide is not only an exogenous compound, but is also produced by yeast during alcoholic fermentation.  An understanding of this is important to ensure successful MLF. Wine Expert- 1407 - SO2 Production by Wine Yeast During Alcoholic Fermentation

Glycerol and winemaking

Glycerol is a non-volatile compound which has no aromatic properties, but which significantly contributes to wine quality by providing sweetness and fullness.  This Issue of 'The Wine Expert' explores its properties and the ways to influence  its production. Wine Expert - 120321 - WE Glycerol and WInemaking

ACETALDEHYDE MANAGEMENT DURING WINEMAKING

The topic of acetaldehyde is very interesting as this compound has SO2 binding properties. The proper choice of wine yeast and bacteria are key factors in determining the final levels of acetaldehyde produced. If SO2 concern is an issue, then choosing a yeast with low final acetaldehyde production such as the Lalvin ICV OKAY® is very important. Wine bacteria can also be an ally as they will use acetaldehyde during malolactic fermentation. If color is an issue, and since acetaldehyde can help stabilize color, then a yeast with medium to high production can be used. When co-inoculation of wine yeast and bacteria is preferred, the acetaldehyde production by the yeast is used by the wine bacteria during malolactic fermentation. A proper fermentation management and nutrition has also been shown to influence the concentration of this compounds, as well as judicious oxygen management. With more and more conscious effort to properly manage the SO2 levels in wines, knowing how the wine yeast and bacteria were characterized for acetaldehyde production becomes a valuable tool for winemakers. This 'Wine Expert ' explores acetaldehyde management in winemaking WE#5 AUSTRALIA2  

CO-INOCULATION OF SELECTED WINE BACTERIA

This Winemaking Expert explores the ever increasing practice of co-inoculation. In France and Spain for example, close to 50% of MLF is now done via co-inoculation. The advantages are numerous, such as ensuring a faster more secure process and reducing time for the MLF. Co-inoculation is an important modulator in sensory development, and it helps limit the development of spoilage microorganisms and thus limits off flavor compound productions. For example, a wine bacteria like the Enoferm Beta can produce higher levels of diacetyl during sequential inoculation.  Co-inoculation on the other hand, will reduce the production of diacetyl and consequently reinforces the fruity character of white wines. Timing of inoculation, interaction with yeast, the presence of precursors that promote the production of aromatic molecules, pH and temperature conditions are all criteria that modulate aromatic expression in wines. Choosing a wine bacteria has become a parameter to take into consideration for developing a specific wine profile.

WE4 Australia