As is common when it comes to hand crafted products made with natural materials, carbon steel knives require a little T.L.C. if they are going to last long enough to become family heirlooms.
The same high carbon content of these blades that gives them such amazing edge retaining properties also can cause them to rust quickly if care is not taken to make sure they are clean and dry after every use. An occasional light rub down with any food grade oil also goes a long way towards keeping them in nice shape.
A carbon steel blade, with enough use, will inevitably develop a patina, which can be thought of as “good” rust. This patina actually will protect the blade from “bad” rust…the redish colored stuff that will leave your blade pitted and damaged. Patinas begin developing naturally and sometimes at an alarming rate when the knife is used for food prep, especially cutting up things like tomatoes, garlic, and citrus fruits. This is perfectly normal and gives the blade character…it’s just important to wash the blade and dry it well as soon as possible after use and before being put away.
Keeping Your Knife Sharp
I don’t suggest letting your blade get terribly dull between resharpenings. This isn’t good for the geometry of the cutting edge, and makes it harder to get the edge back when you do resharpen it.
There’s a multitude of different knife sharpeners on the market, and finding basic instruction on how to sharpen knives/tools is also pretty easy. I have found high quality diamond coated stones paired with a good leather strop/honing compound to be the best system for achieving the hair popping sharp edge that all knives leave my shop with.