When it came to the materials, we went straight to the top shelf. The entire grinder is machined from solid 304 stainless steel, made to resist wear, corrosion, and rust. Unlike 303 stainless steel, which includes sulfur additives to make machining faster, 304 doesn't rely on that sulfur, so it holds up better against corrosion. Surface corrosion is one reason some grinders gum up, tarnish, or rust over time.