:link { color: blue } :visited { color: purple } The excessive production of hydrogen sulphide (H2S) during grape juice fermentation is a widespread problem in wine production (Monk 1986; Henschke and Jiranek 1991). The most common reason for this is inadequate sources of available nitrogen in the juice. To overcome this problem, winemakers can either boost the nitrogen levels in grape must by adding di-ammonium phosphate (DAP) during fermentation, or they can use copper sulphate a...