Certified water flavour standard used to train professional tasters to recognize and scale the intensity of DMS character. Dimethyl sulphide is formed as a result of bacterial growth in water. It can also arise from decomposition of algae following an episode of algal bloom. This compound imparts a sulphury, 'muddy' odour, reminiscent of sweetcorn or tomato sauce.
The best way to assess DMS flavour in water is as follows. Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary.
The flavour threshold of dimethyl sulphide in water is 20 µg / l.
DMS is formed by bacteria growing in water. It can also arise from decomposition of algae in surface waters following an episode of algal bloom.
Dimethyl sulphide is associated with sulphury and ‘muddy’ odours notes. The presence of DMS can also be indicative of contamination of the water supply chain with faecal bacteria.
Indole and skatole may often be found in water in which the DMS has been produced by bacteria. 2-Pentanone may be present in water in which the DMS has been formed by algae.