Bacteria, lactic acid sulfur dioxide effect

Sometimes fermentors must be drawn off before the ideal tannin concentration has been attained. This operation is recommended for stuck fermentations (Section 3.8.1). For reasons already mentioned (Section 3.8.3), these is the risk of development of lactic acid bacteria in sugar-containing musts with inactive yeasts. The volatile acidity would consequently increase dramatically. Drawing off the juice is a means of eliminating the majority of the bacterial population located in the pomace. Sulfiting can be effected at the same time (3 g/hl). This operation may, of course, delay mal-olactic fermentation, but the sulfur dioxide concentration should be calculated to allow the alcoholic fermentation to restart while blocking bacterial activity. 

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