Geranium

geranium, pejorative tasting term for the smell of crushed geranium leaves that is given off by wines in which lactic acid bacteria have reacted with the fungistat (a chemical that prevents fungi from growing) sorbic acid. This geranium smell, which occurs in very varied concentrations and for which the compound 2-ethoxyhexa-3,5-diene is responsible, first appeared in wines during the 1970s, when sorbic acid use became common. Its formation can be prevented by adding sulfur dioxide at the same time as the sorbic acid to prevent the growth and activity of the lactic acid bacteria responsible.