Sensory Terms
3-methyl-2-butene-1-thiol
- Skunk
- Sunstruck
- Sulphurous
- Coffee-like
Cause of Flavour
Occurs primarily in beers that have been exposed to light. Chemicals derived from hops when exposed to light (day and artificial) alter and produce 3-methyl-2-butene-1-thiol or Lightstruck.
Lightstruck is a serious problem in beers that are packaged in clear or green glass. These glass types allow enough of the spectrum of visible light to pass through - interacting with the beer. Beers packaged in brown glass or are canned don't suffer from this problem.
Another solution is to use modified hops - the components cannot be modified by light and do not suffer the same problems with Lightstruck.
Some brands have come to be known for their Lightstruck flavour profile and have turned a defect into a positive flavour.
Other Information
Flavour Level: not normally detected in fresh product
Beer Flavour Wheel Number: 0724
Flavour Level: 0.01 - 2 ug / l
Recommended flavour standard / sensory reference standard of: American Society of Brewing Chemists (ASBC) and the European Brewing Chemists (EBC)