Passivation: Difference between revisions

Metals ions can be released from metal surfaces in contact with the liquid, which may unacceptably change the sensory characteristics of the beverage, or pose a risk for consumers. In particular, iron, chromium, nickel, and manganese can be released from a stainless steel surface that hasn't been properly passivated.<ref name=mazinanian>Mazinanian, N., et al. [https://www.researchgate.net/profile/Yolanda_Hedberg/publication/283246737_Influence_of_Citric_Acid_on_the_Metal_Release_of_Stainless_Steels/links/563203eb08ae3de9381dab54.pdf "Influence of Citric Acid on the Metal Release of Stainless Steels."] ''Corrosion Science and Technology'', vol. 14, no. 4, 2015, pp. 166–171.</ref> [[Iron]] ions as well as other metals are known to have a negative influence on beer and wine flavor stability, largely by increasing the rate of [[oxidation]].<ref name="Zufall">Zufall, C., and Tyrell, Th. [https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.2050-0416.2008.tb00318.x "The Influence of Heavy Metal Ions on Beer Flavour Stability."] ''J. Inst. Brew.'', vol. 114, no. 2, 2008, pp. 134–142.</ref><ref>Narziss, L. [http://www.lowoxygenbrewing.com/wp-content/uploads/2016/11/Narziss-1986-Journal_of_the_Institute_of_Brewing.pdf "Technological Factors Of Flavour Stability."] ''J. Inst. Brew.'', vol. 92, 1986, pp. 346–353.</ref> Specifically, iron catalyzes the formation of oxygen radicals (via Fenton and Haber-Weiss reactions), which then quickly react with components in the beverage to cause staleness (oxidation). See [[Iron]] for more information.