Carbon versus Stainless Steel Blades... An Introduction and Everything You Need to Know
An Introduction to Stainless Steel
Stainless steel contains iron, carbon, chromium, and other elements. The content of iron in stainless steel is roughly 70-88%. The content of chromium is around 11-14%. For steel to be considered stainless, the chromium content must be at least 10.5%. The chrome is what refines the steel and makes it shiny and resistant to rust. Stainless steel sometimes also incorporate other elements into the alloy mixture, such as vanadium, nickel, and molybdenum, to improve the blade's qualities.
Stainless steel knives are more common than carbon steel blades, and they are what people are the most familiar with. Stainless steel requires less maintenance overall, and you don’t need to oil the blade. It is also resistant to developing a patina from cutting certain products such as tomatoes and lemons.
An Introduction to Carbon Steel
Carbon steel has a higher carbon content, which makes it more reactive over time. Most people consider this an “artisanal aspect” of owning premium carbon knives because they change over time and develop a patina.
Carbon steel is a composite of iron and carbon. Depending on the mixture ratio, the amount of iron is usually 98-99%, and the carbon is around 1-2%. This is because pure iron is softer and has other properties that are not conducive to the formation of a blade, so carbon is added so that the steel can reach a certain level of hardness.
What is a Patina?
A Patina is a thin layer that forms on the surface of a carbon steel blade over time. Similar to rust, it is a type of corrosion. It actually improves the rust-resistance, and slowly develops a waves aged pattern on the blade over time. Once a patina has been formed on a carbon steel knife, it acts as a seal and will protect the steel underneath from rusting. Professional cooks prefer this style of knife may because it is truly theirs and carries the uniquely aged marks of their usage.
Carbon Steel Care
Carbon steel knives have what chefs call a “break-in” period, where the knife is developing its patina. With a new carbon steel knife, it is essential to keep the blade dry, and you can also take extra care to oil it after use.
Over the first couple of weeks of using your carbon steel knife, it will slowly form a protective and non-stick patina. Some people say that you should not cut any acidic foods like lemons with a new carbon steel knife because it can accelerate and un-balance the patina process. We don’t think this is the case, as long as you are diligent about cleaning and drying your knife quickly after exposure to these acidic foods.
Some people compare owning a carbon steel knife to owning a cast iron pan. However, we don’t think this is appropriate because cast iron pans require much more maintenance over time and must be seasoned and oiled often. Once a patina is formed in a carbon knife, it requires almost no maintenance from standard sharpening. It is essential to understand that carbon steel blades aren’t high-maintenance. They just need some initial care when they are brand new.
Our View on Accelerating the Patina
Some guides recommend “forcing the patina” manually by exposing a carbon steel knife to certain acidic liquids. We at Masuta do not recommend this because it can damage the blade and “over-patina” the knife, which can damage the alloy's hardness properties altogether.
It is much better to be patient and allow a patina to develop on a blade naturally over time. We think this is a more enjoyable process and comparable to observing plants in a garden grow over time.
Advantages of Carbon
Sharpness and cutting behaviour are the most critical properties of knives. Here carbon knives are way ahead. Because carbon knives are much sharper than stainless steel knives. High-quality stainless steel knives can also achieve a similar sharpness as carbon knives but are usually much more expensive. If you attach great importance to sharpness, there is no getting around carbon steel.
The extended cutting life is another significant advantage of carbon steel. If stainless steel knives and carbon knives were equally hard, then the stainless steel knives have a longer cutting life due to the hard chrome carbides. However, since most stainless steel knives have a Rockwell hardness between 55-59 HRC and carbon knives have a 60 HRC hardness and carbon knives are generally much harder than stainless steel knives. Due to the significantly higher hardness, the blade of carbon knives does not dull as quickly and therefore remains sharp longer.
Since chromium is added to stainless steel knives, some of the chromium becomes chromium carbide. Carbides are very hard and make the grinding process noticeably more difficult. On the other hand, carbon knives consist only of iron and carbon, which is why they do not have any hard carbides that make the grinding process more difficult. Therefore knives can be sharpened on carbon steel very quickly.
Of course, many factors influence the price of knives. In general, carbon steel is cheaper to produce than stainless steel. A decent carbon chef's knife can cost anywhere from $80 to $200, and the most renowned blade forgers even sell their knives for thousands of dollars.
For whom is carbon steel suitable?
Carbon steel is particularly suitable for knife lovers who want unconditional sharpness and always take good care of their knives. In addition, the blades are also ideal for people who are lazy about sharpening but who always take good care of their knives. Those who are interested in traditional Japanese knives will also not be able to avoid knives made of carbon steel.
For whom is stainless steel better suited?
Those who see their knives only as a cutting tool and do not attach much importance to extreme sharpness do not want to dry the knives immediately after use. A clean look is more important than an edge, and should instead choose stainless steel knives. Stainless steel knives are also preferable in very humid environments where the blades are regularly exposed to moisture.
Carbon steel has its advantages and disadvantages and will always be preferred by certain people and avoided by others. In the end, it depends on what you use the knives for and which characteristics are individually more critical.