What is Carbon Steel?

Carbon steel is steel with minimal alloying. Typically ‘stainless steel’ is mixed with nickel or chromium to make it stainless and resistant to rust, but these alloys are only mixed in with the iron, there is no chemical bonding between the different elements. These elements will clog up whetstones during sharpening. Carbon steel is essentially steel without these elements mixed in.

Carbon steel knives that are heat treated effectively are capable of the highest levels of sharpness whilst being generally easier to sharpen and are beloved by chefs in heavy use settings.

However carbon steels can rust very easily and need special care and attention, usually by oiling the blades after use to prevent rust. Carbon steel knives should also be washed and dried immediately after use, even salt from your hands will rust the blades. Carbon steel knives will naturally discolour on the blade forming a ‘patina’. The patina will protect the steel underneath, and some say that the natural discolouration, showing the use of the knife is quite beautiful.

Whilst traditional carbon steel knives are still made by some brands like Sabatier. Many new carbon steels have been released by various Japanese mills which contain tungsten, manganese, vanadium and or chromium. The addition of these elements provides harder wear and corrosion resistance of course, at the cost of the impurities in the steel. These new carbon steels provide some balance between the corrosion resistance and hardness of stainless steel with the ease of sharpening of pure carbon steel.

Whilst many variants exist, some branded steels have become especially popular with knife manufacturers:

Shirogami – A high carbon steel with minimal impurities

Aogami Super – Also known as Blue Paper Steel or Blue Steel, is an alloyed with Tungsten, chromium, manganese and vanadium. A very pure steel containing hardly any flaws like sulphur Edge retention is increased dramatically, Aogami steels can achieve a hardness of over 60 HRC and can go up to 65 HRC. Considered the ‘gold standard’ steel for knife making.

Aogami 1 & 2 – Also known as White Paper Steel. Similar to Blue Paper steel with increased alloyed elements, can be harder but more brittle.

The best carbon steel knives are often cladded in stainless steel, or super premium knives can be cladded in stainless Damascus steel. This means that only the tips of the knives are exposed, lowering the risk of damage from rust.

Generally we do not recommend carbon steel knives for anyone but the professional chef.