Citric Acid and Stainless Steel. Cleaning and Passivating a fermenter.
I recently drilled out my 14 gallon Chapman bucket fermenter to have a ball valve, a thermowell, and then added a triclamp fitting to the top. Everything was water tight and held like a champ. I thought I had done a sufficient job of cleaning the fermenter after drilling it out by using pbw, a rinse, and then starsan. I then added a blonde into the fermenter. Upon taking a sample of the blonde before transfer all I could taste was a strong hint of metal. The same batch of blonde went into a glass carboy for a blueberry addition and came out fine. Thus I'm sure the fermenter was the cause of the metal taste. I've been doing some light reading on cleaning stainless with acids and passivating stainless. So here are my questions.
Who has used citric acid to success?
Where did you get your citric acid and will this (see link below) work?
Thank you in advance!