I have always been told to passivate with Nitric Acid before the first brews on a new system. Of course yearly passivate is key to keeping your steel protected and in top shape.
Anyone care to add to passivating techniques that have worked for them?
For my last buildout, we did a full caustic of all internal surfaces, then a Phos/Nitric blend cycle, then a heavy duty straight Nitric Acid cycle for 60 minutes to passivate.
matthewbrews @ gmail (dot) com