isovaleric acid

3.0 mg er capsule

Isovaleric, like stale cheese or sweaty socks”

Certified beer flavour standard used to train professional beer tasters to recognize and scale the intensity of isovaleric character. Isovaleric acid imparts a cheesy off-flavour to beers. The flavour arises from use of hops or hop products which have deteriorated in quality prior to use.

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

Flavour cards

Flavour standard information

Technical specification

The best way for assessors to evaluate isovaleric flavour in beer is as follows. Cover the beer with your hand and swirl the glass to release the aroma. Remove your hand and take a single long sniff. Repeat as necessary.
Amount of flavour per capsule
3.0 mg er capsule
The flavour threshold of isovaleric acid is 1 mg / l.
Isovaleric acid is derived from breakdown of alpha-acids in hops. It is imparted to beer by use of high hopping rates or degraded hops or hop extracts. Isovaleric acid can occasionally be produced by wild yeasts, specifically Brettanomyces spp which may be present either as contaminants or introduced into beer for conditioning purposes.

Professional beer tasters can confuse isovaleric acid with the following flavours:

  • Butyric acid
  • Ethyl butyrate
  • 2,3-Butanedione
Isovaleric, sweaty, cheesy flavour notes are characteristic flavours of some beer styles, eg India Pale Ale. Typical ‘cheesy’ characters are often associated with beers of very high bitterness. In pale lager beers, isovaleric character is regarded as an off-flavour.
CAS registry number
The CAS registry number of isovaleric acid is 503-74-2.
Other names
  • 3-methylbutanoic acid
  • isobutyl formic acid
  • delphinic acid
  • dephinic acid
  • 3-methyl butanoic acid
  • 3-methyl butyric acid
  • beta-methyl butyric acid
  • 3-methylbutanoic acid
  • isopentanoic acid
  • isopropyl acetic acid
  • isovalerianic acid
The intensity of isovaleric flavour increases with decreasing beer pH value.
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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Isovaleric beer flavour standard
earn 9 points

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