A carbon steel blade is unequaled in its ability to take an extremely sharp edge, and therefore it is preferred by most serious chefs. The major drawback of carbon steel is that unless the blade is promptly wiped dry after each use, it will rust. The alloy is also vulnerable to attack by the acid in foods like citrus fruits, tomatoes, and onions. If the knife is not washed soon after contact with these ingredients, the acid will react chemically with the metal, blemishing the blade's surface with blackish stains. Moreover, that discoloration and its attendant off-odor can be transferred to the foods you are cutting.
Super stainless steel is the least efficient of the four basic knife alloys. It is all but impossible for a cook to restore the sharpness once the knife loses its original well-honed edge (if the manufacturer gave it one in the first place). Kitchenware demonstrators speak hokum when they claim that super stainless steel knives never need to be sharpened. What they should tell you is that their product can't be sharpened.
Stainless steel, like its super cousin, resists rust, stains, and corrosion caused by water and acid. Though it takes a sharper edge than a super stainless one, a stainless steel blade will still be annoyingly dull in the hands of a busy cook.
A high-carbon stainless steel knife - by far the most expensive of the four types - will neither rust nor stain. Consequently, it is the answer for a cook who lives by the sea or in a humid climate, because salt can corrode and moisture can oxidize (rust) non-stainless steel. High-carbon stainless steel is also recommended for cooks who do not want to be bothered with having to wash the knife and wipe it dry promptly after each use - or who do not want the knife blade to become tarnished because the chore was neglected.
Although a blade made from high-carbon stainless steel can be honed to a fairly sharp edge, do not believe the food writers and salespeople who tell you that its sharpness will match that of a knife made with carbon steel as this is physically impossible.
