A distinctive flavour of beer with the character of cooked vegetables, cabbage, sweetcorn or brussel sprouts. Arises from the thermal decomposition during boiling of precursors such as S methyl methionine from malt. DMS is very volatile and will be driven off by the vapours produced in boiling. However, if wort is kept hot for a period after boiling it will accumulate DMS to levels which may be detected in beer (above 90 mg per litre). DMS may also be produced by bacterial contamination and so indicates poor handling.