Unpleasant bitter. earthy and rancid odor and taste after grated leaves and flowers of geraniums (popularly geraniums), which is caused by reaction of the preservative sorbic acid With bacteria like acetic acid or Lactic acid bacteria arises. The wine faults can for example at the malolactic fermentation (BSA) occur where lactic acid bacteria are active. The problem first appeared in the second half of the 20th century when it became more common, the grape or add wine sorbic acid.
In the case of bacterial infection, this is caused by reaction with ethanol (Alcohol) converted to 2-ethoxy-3,5-hexadiene. Even the smallest amounts of the very intensely tasting substance in ten billion times dilution are clearly perceivable as geranium clay. Troubleshooting is almost impossible, not even through activated carbon, The error can only be prevented by great basement hygiene, possible distribution sources are contaminated containers (fermentation tanks, barrels, bottles), hoses and filling systems. See also under wine faults,