by Marjorie Steele, Editor for IQS
If you’re anything like me, the image of a stainless steel brewery tank conjures warm, happy feelings. The kind of feelings that can only be found at the bottom of a good pint.
Amateur beer connoisseurs like myself often appreciate the brewmaster’s careful blending of hops, malt and yeast, but the industrial manufacturing process responsible for fabricating sanitary grade brewery tanks is usually overlooked. As always, industrial processes play a vital role in each and every element of our daily lives – and what could be more vital than beer?
Also used in dairy processing tanks, sanitary grade stainless steel tanks have a very specific type of finish. A sanitary finish, which is typically matte, is applied through electropolishing, as opposed to more typical mechanical and brushed finishes. The electropolishing process consists of a temperature-controlled bath in an electrically conductive solvent and a direct electrical current which is introduced to the bath. The result is that the outer surface of metal is completely removed with the kind of precision that can only be achieved through electrolytic processes. Sub-microscopic peaks and valleys on the surface of the stainless steel are removed, and the stainless steel regenerates a surface layer of passivised chromium oxide to protect it against rust and corrosion.
This is crucial for proper beer fermentation as well as for sanitation standards, for without the removal of these molecular-level gutters and valleys, particles of yeast, sugar and other ingredients would be trapped within the wall of the tank long after scouring. Sugar and yeast would remain and flourish in non-sanitary finishes, growing bacteria and yeast the brewmaster had not counted on. Yeast trapped within brewery tank walls could change the chemistry of the beer’s fermentation, and we don’t want to think about what the bonus bacteria would do.
Next time you visit your favorite brewery, take a moment to include an appreciation for the stainless steel tank manufacturers who make it possible for brewmasters to harness the chemistry of their brew.
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