4.5 µg per capsule

Mercaptan, like drains or rotting garbage”

Certified beer flavour standard used to train professional beer tasters to recognize and scale the intensity of mercaptan character. Methanethiol is the main thiol found in beer. It arises due to yeast autolysis at the end of fermentation. At low levels it contributes to the flavour complexity of fresh beer; at higher levels it is an off-flavour.

Food grade | free from sensory impurities | extensively tested | safe to smell and taste.

Flavour cards

Flavour standard information

Technical specification

The best way for tasters to evaluate mercaptan flavours in beer is as follows. Without covering the glass, swirl the beer to release the aroma. Take a single short sniff. Repeat as necessary.
Amount of flavour per capsule
4.5 µg per capsule
The flavour threshold of methanethiol in beer is 1.5 µg / l.
Methanethiol arises through yeast autolysis at the end of fermentation or during maturation. It can also be contributed to beer by dry hopping and by growth of bacteria in beer.

Professional beer tasters can confuse methanethiol with the following flavours in beer>

  • Ethanethiol
  • Dimethyl trisulphide
  • Sulphur dioxide
Methanethiol is a component of the sulphury flavour character of beer. It is found in all beer styles to a degree. Methanethiol and other thiols are off-flavours when present in excess.
CAS registry number
The CAS registry number of methanethiol is 74-93-1.
Other names
  • methyl mercaptan
  • mercaptomethane
  • methane thiol
  • methyl sulfhydrate
  • thiomethanol
  • thiomethyl alcohol
Methanethiol is the main thiol found in beer. Other thiols give similar flavour notes which have subtle differences in relation to their flavour associations.
Threshold distribution
Capsules per pot
Legal notices
This product is protected by the following trade marks and patents:
  • US Patent no. D679900
  • European Community Trade Mark
    Registration no. 009937574
  • European Community Trade Mark
    Registration no. 009856527
  • US Trade Mark Registration no. 4345057
  • US Trade Mark Registration no. 4345056
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Mercaptan beer flavour standard - methanethiol
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