Patina on a high-carbon steel knife after weeks of heavy use
HELP!!! My knife’s finish has changed! What’s going on?
Your knife is made from high-carbon steel alloys such as Apex Ultra, 1084, 15N20, and W2. Each has characteristics that make it ideal for its chosen application: Holding a sharp edge, resisting chipping, breaking, or rolling, etc.
High-carbon steel will develop a patina as it’s used, somewhat uneven at first, and then becoming a uniform, slightly darker coating with time. The effect can be accelerated if you frequently prepare acidic foods (lemons, tomatoes, pickles), or if you leave food residue on the knife for long periods of time.
Patina can be polished off, but most chefs prefer to leave it as it provides additional protection for the blade. If you prefer to retain the original shiny, bright finish for years to come, however, you can request that your knife be made with a stainless steel alloy.