Expertise documents

Nitrogen is an essential nutrient for smooth alcoholic fermentation (AF). Numerous  studies have shown that nitrogen has a positive impact on the growth and fermentation activity of yeast (Bell et al. 1979, Ough and Lee 1981, Bezenger and Navarro 1987). Deficiencies in yeast-available nitrogen (YAN) in the must significantly increase the risk of sluggish or stuck fermentations because they can arrest protein synthesis in the yeast cells. We consider a must with an initial sugar level of about 200 g/L to be deficient when its YAN concentration is about 150 mg/L (Henschke and Jiranek 1993). A YAN deficiency in the must can also cause the yeast to increase the production of H2S (Henschke and Jiranek, 1991). This edition of the Winemaking update focuses on the impact of balanced nutrition on alcoholic fermentation.

Lallemand Winemaking Update #13 2010 - Balanced nutirtion

The utilization of specialty inactivated yeasts (SIY) in winemaking has gained popularity in recent years, and their uses are varied. For example, SIY can be used as protectors during yeast rehydration and as a nutrition tool during fermentation. As we understand more about the yeast cell constituents, the production process, the characterization of each yeast strain and their unique fractions, we can obtain very specialized inactivated yeasts to yield specific results under defined conditions. Such is the case for the inactivated yeasts that can trigger specific responses during fermentation due to their unique functionalities. This issue of the Winemaking update will focus on a new SIY designed for white and rosé wines.

Lallemand Winemaking Update #16 2011

 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

In 2006, the world production of rosé wines was estimated at 21.5 million hL – 9% of the total world production of wine (Aigrain 2009). Production has been increasing for several years. In the United Kingdom, for example the main sellers are rosé wines from the United States – almost half of the total wines sold in supermarkets. From a technical point of view, the production of rosé wine involves particular considerations as rosé is mid-way between white wine (avoiding the extraction of phenolic compounds at the tannin level) and red wine (involving potential problems with colour extraction and structure). When short maceration times are used in the production of high quality rosé wines, the wines can be fragile and evolve rapidly. One of the most frequent developments is the appearance of premature lactic and creamy aromas that can override the fruity aromas in the nose and the refreshing sensation in retronasal perception. This issue of Winemaking Update focuses on some points to consider during fermentation - please click on the link to see the full articleWUP #2- 2012 Rosé Australie