As prefessional stainless steel beer growler producer, We use 18/8 stainless steel, or SUS 304 food grade stainless only for all our beer growlers, with inner side passivated. We adopt all kinds of up-to-date technology in production, including water bulge, laser welding, rolling formation, electro-chemical etching, laser marking, acid passification. powder coating, etc. Our customers including major North America water/drink/beverage/ bottle and beer growler suppliers.