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Isovaleric acid can also be produced by the oxidation of hops <ref>[http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1970.tb03256.x/pdf Green, C. P. The Volatile Water-Soluble Fraction Of Hop Oil. Aug 24, 1909.]</ref><ref>[https://books.google.com/books?id=oWQdjnVo2B0C&pg=PA498&lpg=PA498&dq=oxidation+of+hop+resins+3-Methylbutanoic+acid&source=bl&ots=wmM8jX-qJY&sig=_wFzzuUA40eg0vMNc-7vfU6tneA&hl=en&sa=X&ei=XX2PVJHDI4bcoATjoYK4BA&ved=0CEcQ6AEwBQ#v=onepage&q=oxidation%20of%20hop%20resins%203-Methylbutanoic%20acid&f=false Oliver, Garret. The Oxford Companion to Beer. 2001. Pg 498.]</ref>.
==Metabolic Breakdown==
''Brettanomyces'' can break down isovaleric acid into an ester called ethyl isovalerate. This ester is described as fruity, sweet, berry-like with a ripe, pulpy fruit nuance <ref name="Fenaroli_ethylisovalerate">[https://books.google.com/books?id=15HMBQAAQBAJ&pg=PA638&lpg=PA638&dq=ethyl+valerate+threshold&source=bl&ots=avVr8PQQ_p&sig=zm81_lhLU86VJ4jBNnm4I9nnxDw&hl=en&sa=X&ved=0CDIQ6AEwBGoVChMImYrEl6usxwIVAjmICh1HGwEs#v=onepage&q=ethyl%20isovalerate%20threshold&f=false Fenaroli's Handbook of Flavor Ingredients, Fifth Edition. George A. Burdock. CRC Press, Dec 3, 2004. Pg 587.]</ref><ref name="Joseph">[http://www.ajevonline.org/content/suppl/2015/07/28/66.3.379.DC1/Supplemental_Data.pdf Supplemental Data for: Joseph, C.M.L., E.A. Albino, S.E. Ebeler, and L.F. Bisson. Brettanomyces bruxellensis aroma-active compounds determined by SPME GC-MS olfactory analysis. 2015.]</ref><ref name="lucy_joseph">[http://slideplayer.com/slide/4473144/ Impact of Brettanomyces on Wine. Presentation by Lucy Joseph of UC Davis. Retrieved 08/15/2015.]</ref>. The rate of metabolic breakdown of isovaleric acid into ethyl isovalerate has not been researched, as far as the authors of this wiki know. See also [[Brettanomyces#Ester_Production|Brettanomyces ester production]].
==References==