Expertise documents

Biogenic amines are found in fermented food and beverages, including wine. Of the many biogenic amines, histamine, tyramine and putrescine are the most important in wine. It is the metabolism of amino acids by lactic acid bacteria that produce the biogenic amines found in wine. Red wines tend to have higher biogenic amines content than white wines, as this wine type all under go the bacteria driven malolactic fermentation. The direct decarboxylation of amino acids results in the formation of biogenic amines. Extensive biochemical and genomic characterisation has led to simple tests for the identification of biogenic amine genes in LAB strains. Wines produced using native microflora can have high biogenic amine content. Consumer safety justifies taking extra precautions to avoid the production of biogenic amines. Good winemaking practices should be used to avoid the production of biogenic amines; management of must and wine pH to minimise the proliferation of native microflora, stabilise musts or wines for antimicrobial protection with SO2 or new biological solutions (such as Bactiless™) and use malolactic bacteria strains (and particularly in co-inoculation) that have been screened for the absence of biogenic amine genes. Compatible with organic winemaking or in a strategy to reduce chemical additions, the use of malolactic bacteria is a key step to achieve wines with low to no biogenic amines. WE Biogenic Amines - ENG

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

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  

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