5.0 mg per capsule

Bitter, like beer”

Certified beer flavour standard used to train professional beer tasters to recognize and scale the intensity of bitter character. Iso-α-acids are contributed to beer via hops. The bitter taste they impart is one of the five basic tastes and a critical flavour character in beer.

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

Flavour cards

Flavour standard information

Technical specification

The best way to detect hop bitter acids in beer is as follows. Take a little beer into your mouth. Move it around with your tongue for a few seconds then swallow it.
Amount of flavour per capsule
5.0 mg per capsule
The flavour threshold of iso-alpha-acids in beer is 3 mg / l.
Iso-alpha-acids are imparted to beer through addition of hops or hop extracts in the brewhouse or post-fermentation. The intensity and quality of the bitterness depends on the hop variety, hopping practice, and brewing process.

Bitterness due to iso-alpha-acids in beer can be confused with the following:

  • Ferrous sulphate
  • Sodium bicarbonate
  • Octanoic acid
Iso-alpha-acids are one of the five basic tastes found in beer and a major differentiator of styles and products. Important flavour note in lagers, ales and stouts. Bitterness of this type is a signature flavour note in India Pale Ales.
CAS registry number
The CAS registry number of iso-alpha-acids is 25522-96-7.
Other names
  • iso-alpha-acids
  • iso-a-acids
  • hop bitter acids
  • cis-iso-alpha-acids
This flavour standard is rich in cis isomers of the iso-α-acids, which are more bitter than their trans counterparts. This allows us to employ a smaller amount of material than might be expected to produce the desired flavour impact.
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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Bitter beer flavour standard - iso-alpha-acids
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