But…if the whiskey is acidic, then aren’t they basically passivating their flask? If whiskey is acting as an acid, it’s removing/dissolving the free iron that may be on the flask. I’m assuming it’s SS, which means an acidic liquid will react with the chromium to produce a thin layer of chromium oxide on the walls of the flask, but I doubt it would actually dissolve or strip the chromium off….I use bright tanks at work and when a tank is passivated, we circulate through the tank a low pH (1) nitric or citric acid cleaner, drain, and it is left to air dry, according to the instructions given by the company supplying the acid cleaner. I don’t understand why you predict the chromium is being stripped off, when acid cleaners are used to reinforce the chromium oxide layer on SS in CIP cleaning methods.