Why is my stainless steel grill rusting or discoloring?

Outdoor stainless steel grills take a lot of wear and tear. They are exposed to weather, heat, food, cleaning chemicals, scratches and more which makes them especially susceptible to corrosion and blemishes. And while the name itself – stainless – seriously implies no staining, not many things in life are infallible. They require care and routine maintenance to maximize longevity. Stainless steel grills are one such example. Depending on the grade, thickness and finish of the stainless, over time, they may develop some rusting or discoloration. However, with proper handling, these problems can be minimized.     

What causes the rust?

Stainless does not actually “rust” like regular steel where a red oxide appears on the surface that flakes off. So, if you see red rust, it’s likely due to some iron particles (e.g., steel wool) that have contaminated the surface of the stainless steel and it is those particles, not the stainless, that are actually rusting. Additionally, humidity, excessive moisture and salt in the air (as found in coastal areas) may cause small rust pits to develop on the grill’s surface as will certain concentrate bleaches and other cleaning solutions containing chlorine.

What causes the discoloration?   

Stainless steel gas grills have a layer of chromium oxide on them. This layer is designed to protect from corrosion. However, this layer may sometimes be penetrated which would lead to some discoloration over time.  For example, here is an image to consider. Place a wet cast iron skillet in a stainless steel sink and you’ll usually see a rusted ring left behind. While the sink did not actually rust, it did get discolored. And, when it comes to stainless steel grills where cooking is the primary activity, smoke and heat can also create a coating on the stainless that may eventually discolor the stainless steel surface.