If you are going to use a carbon steel knife, it will undergo some changes through use and exposure to different elements and foods. Here are some things that can happen:
Patina: Carbon steel tends to develop a patina, a thin layer of oxide, on the surface. This is a natural process and helps to protect the blade against corrosion. The patina can vary from dark blue to black, depending on use and environment.
Food discoloration: When using a carbon steel blade, some foods, such as sour fruits or onions, may show a slight discoloration. This is completely normal and does not affect the taste or safety of the food.
Maintain sharpness: Carbon steel blades generally have excellent sharpness and can retain this sharpness for a long time. However, regular sharpening and maintenance is important to maintain sharpness.
Susceptibility to corrosion: Compared to stainless steel, carbon steel is more susceptible to corrosion. It is important to clean and dry the knife properly after use to prevent rust.
Development of a unique character: Over time, a carbon steel knife takes on a unique appearance and character. It can develop minor scratches, discolorations and patina that give the knife a personal look.
It is essential to know that carbon steel blades require a little more maintenance than stainless steel blades. However, by properly maintaining them, you can enjoy the excellent sharpness and performance they offer.
White steel, also known as: Shirogami/White paper/Shiroko steel
This traditional steel is not named after its colour, but named after the colour of its paper wrapping, in which it is stored in the Hitachi steel factory in Japan. There are 3 grades of Shirogami white steel: #1,#2 & #3. From these 3, #1 contains the highest amount of carbon and #3 the lowest. Generally we say at our knifeshop, grade #1 can be made extremely sharp, but will be a little more fragile as #3. While #3 is a little softer, also easier to resharpen, but has less edge retention. Grade #1 & #2 is most common in white steels. White steel is a refined steel with a low percentage of iron, loved by many, as it is relatively easy to maintain. In practice it can be maintained with a whetstone and in a short amount of time it will become very sharp. This does not mean that these knives never have to be resharpened by a professional, even all knives in Japan need to be refurbished at a certain moment. This Shirogami steel is embraced by sushi chefs who demand extreme sharpness of their knives. White steel oxidates relatively quick and therefore needs to be maintained more often, but on the other hand you will get all benefits of this beautiful steel characteristics.
Blue steel, also known as Aogami/Aoki steel
This traditional steel is not named after its colour, but named after the colour of its paper wrapping, in which it is stored in the Hitachi steel factory in Japan. There are three different grades: super, #1 en #2. Blue steels use a high grade of carbon, chrome and vanadium added in their alloy. Aogami super even added extra tungsten. Aogami super is here " Best of both worlds" Blue #1 is for sharpness, Blue #2 for toughness. Blue steels are mostly seen in deba or usuba knives, white steels often in yanagibas. Aogami super is regarded as one of the best traditional steels by Japanese knifemakers, but difficult to work with. Blue steels are difficult to sharpen on a whetstone, but they remain sharp for a longer period, compared to white steels.