This complex wine defect manifests itself in a dull, musty and sometimes pungent vinegar-like smell or disgusting taste. The wine-unfamiliar impression is quite similar to the dreaded cork taint. The defect is caused by various moulds, the most common genera being Penicillium and Aspergillus. One of the causes is grapes that have been affected by one of the many types of grape rot, such as grey rot (Botrytis) or green rot, or whose berries have been damaged by external influences such as pest damage or heavy rainfall. If the cause was white rot on the grapes triggered by hail, this is called hail blight. Another main reason is lack of hygiene in the cellar. This can cause mould to form in the must, on wine residues, on tartar found in wooden barrels and on cellar equipment. In the case of barrels, this is prevented by wet pres ervation or dry preservation. The wine is treated with activated carbon. A similarly manifesting defect is barrel t aint.