Porcelain enamel (also known as Vitreous enamel) is a specially formulated, highly durable glass permanently fused to metal under extremely high temperatures. The metal may be steel, cast iron, or aluminum. It may be a protective surface for cooking utensils, kitchen and bathroom fixtures, and appliances such as dishwashers, ranges, and refrigerators. It is acid resistant. Porcelain enamel may be a decorative surface of metal, glass or pottery.

Porcelain enamel has many excellent properties: it is smooth, hard, chemically resistant, durable, can assume brilliant, long-lasting colors, and cannot burn. Its disadvantages are its tendency to crack or shatter when the substrate is stressed or bent.

Flat matte finish.
About 1 mill thinner than the glossy, the flat matte is considered by the enamel industry to be more heat resistant, will survive thermal shock better, will not chip like glossy, has a lower reject rate in production, and dramatically reduced warranty claims. For these reasons it has become more popular with manufacturers in recent years. Expect to see more of this porcelain finish on grill parts, especially cooking grids.

Glossy finish.
The standard for many years, this finish is preferred by many consumers because, in some people's opinion, it looks good, and by marketing folks because, well, because customers like it. However, it is more easily chipped than the flat matte, and shows blemishes more prominently. Some believe the glossy finish cooking grids are easier to clean but the jury is still out on this one.