Expertise documents

The New Winemaking Update – Organic Version: Copper sulfate use in organic vineyards – are wine yeast and bacteria affected by this fungicide?

In 2017, the organic vineyard areas had tripled in 10 years and approximately 5% of worldwide vineyards are now under organic certifications.  For organic growers, who cannot use other fungicide sprays, copper sulfate is still an effective tool against downy mildew. With the increased production of organic vineyards in the world, the use of this fungicide has also grown with the expansion of this type of farming. It is known that elevated concentrations of this metal can be toxic to yeasts and bacteria. Our results have shown that wine yeast and bacteria do not appear to be significantly affected by Cu concentrations higher than 15 mg/L, except in the case of malolactic fermentation in white wines, where concentration > 7.5 mg/L can impact the MLF. High pH and high Cu concentrations can impact wine yeast viability and lag phase. To read more about this topic, please consult our Winemaking Update - Organic Version WUP Organic 2020 Cu- ENG LR

Wine bacteria to control volatile phenols from Brettanomyces

This issue of the Winemaking Update explores a natural way to control Brettanomyces yeast and the volatile phenols they produce, with selected wine bacteria used to conduct malolactic fermentation.

WUP #2 2014 Australia

 

A new concept of Lactobacillus plantarum wine bacteria in high pH wines

This edition of the Winemaking Update presents the latest findings on the use of Lactobacillus plantarum wine bacteria based on new concepts for achieving MLF and for limiting the growth of indigenousflora and possible harmful wine microbes.

WUP No 1-2015 ML Prime - Australia

Sculpting the aromatic profile of wine through diacetyl management

 In addition to carrying out the bio-deacidification of wine, malolactic (ML) bacteria influence aroma and flavour through various mechanisms, including the production of volatile grape- and yeast derived metabolites. In wine, one of those volatile compounds – diacetyl – has important stylistic implications. This diketone, also known as 2,3-butanedione, is associated with the “buttery” character of wine and is formed as an intermediate metabolite in the reductive decarboxylation of pyruvic acid to 2,3-butanediol.The formation and degradation of diacetyl is closely linked to the growth of such ML bacteria as Oenococcus oeni and the metabolism of sugar, malic acid and citric acid. Yeasts are also able to synthesize diacetyl during alcoholic fermentation (AF). However, most of this diacetyl is further metabolized to acetoin and 2,3-butanediol. This issue of Winemaking Update will review winemaking practices and the latest findings to help modulate diacetyl content in wine through malolactic fermentation (MLF).

Lallemand Winemaking Update #15 2012 - Diacetyl Management