Many high carbon steels make for fantastic kitchen knives. High carbon steel typically takes and holds a very sharp edge which is needed for kitchen knives to cut cleanly. Some high carbon steels can also develop a hamon when heat treated in a specific way. If done correctly a hamon can look beautiful and add real character to the appearance of any knife. Plus in many cases carbon steel knives can outperform stainless steel knives in common kitchen cutting tasks. However there has to be a drawback and in the case of high carbon steel it comes in the form of rust/tarnishing.
Unlike stainless steel, high carbon steel starts to rust quite quickly when exposed to moisture. Rusting can be prevented or limited in a number of ways, all of which are very simple to do.
The first way to prevent your high carbon steel kitchen knife from rusting is to simply hand wash it straight after using it and then dry it thoroughly. It's no more complex than that. Some people like to give the steel a light coat of oil before putting the knife away; some use mineral oil but we prefer veg oil as it's food friendly. For knives that aren't going to be coming into contact with food we'd recommend 3-in-1 oil. It's cheap and very effective at limiting rust.
Whatever you do, do not put your handmade kitchen knife through the dishwasher! Not only do you run the risk of the handle being damaged but it may also cause pit marks or rusting of the high carbon steel blade. You wouldn't take a handmade Aston Martin through a car wash, you'd hand wash it with care and then put it away in the garage once you'd finished with it. That's also the best way to treat your handmade knives; hand wash them, dry them then put them away.
The second way to help prevent the knife blade from rusting is to let the blade develop a patina. This happens as the surface of the steel reacts with various foods. As a patina forms the steel will start to develop patches of grey, blue and other colours where the blade comes into contact with the food. This makes for a very unique pattern on the blade, making your handmade knife a true one-off and telling the story of its use. The most common ways to develop a patina on a knife include chopping several onions or smearing mustard on the blade, leaving it for a minute or so before cleaning it off and neutralising the reaction with a rub of bicarbonate of soda.
Whether you purposefully create a patina or not, a high carbon steel blade will naturally develop one through use over time. You can reduce or remove this if you prefer the shiny/unused look though a liberal application of elbow grease and a sponge. If the patina is very well developed or you have rust marks then it may be necessary to give the blade a quick polish with some baking soda or gentle metal polish and a scouring pad. However you're likely to find yourself doing this quite a lot as a patina will reform once you've used the knife a few more times.
We make knives in a range of both stainless and high carbon (non-stainless) steels so if you want a knife that requires a little less looking after then you should take a look at our range of handmade stainless steel kitchen knives. They combine the best handle materials with really high performance stainless steels that are designed specifically for knives.