Those familiar with the Scottish soft drink Irn-Bru may be familiar with the marketing slogan: "made from girders." This is due to the drink's taste which some describe as having a metallic edge.

The actual recipe remains a secret, however there is a large range of imitation drinks and unbranded "iron brew" flavoured products (e.g. syrups, confectionery, etc.) with the same taste, so the general flavour recipe must be fairly widespread knowledge within the flavouring industry.

I've searched but unlike cola-flavoured beverages, whose flavours have been scientifically studied and for which recipes exist, there is no information about the makeup of iron brew.

So does anyone know... what are the flavours or aroma compounds which go into making an iron brew taste?


1 Answer 1


AG Barr answered that a while back in releasing the fact the Ammonium Ferric Citrate was a key ingredient in flavouring the drink. That, however, is not the full story.

If my memory serves me correctly, UK food labelling regulations allow the catch-all term "Flavourings" to allow a manufacturer to maintain intellectual property rights for their recipe.

Other than that, the ingredients most-to-least (apart from the actual percentages which are protected under the same legislation) are as follows:

  • Carbonated Water
  • Sugar Acid (Citric Acid)
  • Flavourings (Including Caffeine, Ammonium Ferric Citrate & Quinine)
  • Sweeteners (Aspartame, Acesulfame K)
  • Preservative (E211) Colours (Sunset Yellow FCF, Ponceau 4R)

(Contains a source of Phenylalanine. Sunset Yellow & Ponceau 4R)


  • Thanks for the response, but I'm actually trying to find out which flavour compounds make up an iron brew taste rather than just a list of non-specific ingredients. For example, a typical "cola" taste is made from extracts of orange, lime, cassia, lemon, nutmeg, coriander, neroli, lavender (see OpenCola). I'm looking for an equivalent list for an iron brew taste.
    – WackGet
    May 31, 2021 at 22:12

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