This wine defect, which usually occurs after alcoholic fermentation, can be caused by malolactic fermentation that has not proceeded correctly. Synonyms are butyric acid sting, yoghurt clay, whey clay and sauerkrautton. Uncontrolled acid reduction can lead to infections with lactic acid bacteria of the genus Pediococcus and Lactobacillus. These produce the aroma substance diacetyl, which gives the unmistakable and typical buttery (lactic) or herbaceous note. The defect is expressed by a typical slightly sweet-sour smell and taste of yoghurt, buttermilk, cheese or sauerkraut and thus also a milky cloudiness in the wine. Wines low in acidity and tannin with a high pH value are particularly at risk. Activated carbon is used to combat this wine defect. A quite similar wine defect is the Lindton.