Anodising process for alloys of aluminium generally, controlled surface corrosion within treatment baths that then make it resistant to deterioration unless scrathed or damaged.
Ferrous base material plating, thoughts are that copper and copper alloys aren't fully resistant to ethanol and may not give a fully resolved solution. Zinc potentially more useful and not originally done by manufacturers for cost reasons, probably right as they've essentially outlasted any service life prediction at a guess.
Enquiry to platers regarding logistics of tank internal may yeald a practical path.