Getting to know carbon steel knives.

Buying your first high carbon steel knife can be both exciting and intimidating. These knives are prized for their ability to achieve an incredibly sharp edge and their ease of sharpening. However, there's one downside to consider: they are prone to rusting.

Many newcomers to high carbon steel knives worry that even the slightest exposure to moisture will cause irreparable rust. While it’s true that high carbon steel can rust if not properly cared for, it’s not as fragile as it might seem. With a few simple maintenance tips, you can keep your knife in great condition for years to come.

High carbon steel is made primarily of iron and carbon. The higher the carbon content, the harder the blade, which means it can hold a sharper edge. But harder doesn’t always mean better. While a harder blade can achieve a finer edge, it also tends to be more brittle. This is fine if you're using your knife for delicate tasks (like sushi slicing), but if you plan to cut through tougher materials, like bone, the hardness can work against you.

Steel hardness is measured on the Rockwell Hardness Scale (HRC), and most high-quality kitchen knives fall within the range of 55 to 65 HRC, with some exceptions. A standard chef’s knife made from high carbon steel typically falls around 58–63 HRC, which strikes a good balance between sharpness and durability.

When chopping moist ingredients like tomatoes, cucumbers, or celery—or acidic foods like lemons and limes—be sure to wipe the blade off periodically. Leaving the blade wet can lead to oxidation, which over time can turn into rust. As you use your knife more, a natural patina will form on the blade. This non-corrosive layer helps protect the steel and reduces the chance of rust. That said, avoid leaving your knife submerged in water (and certainly never put it in the dishwasher!).

If you do notice a bit of rust on your blade, don't panic. Simply apply a little lemon juice to the affected area and rub the spot with the skin of the lemon. The rust should come off easily. For more stubborn rust, you may need to use fine-grit sandpaper to gently remove it. If your knife features a hamon line (a distinctive visual feature seen in some handmade knives), it’s best to contact the maker for specific advice on rust removal to avoid damaging the blade’s appearance.

With proper care, your high carbon steel knife will not only maintain its sharp edge but will also develop a beautiful patina that tells the story of its use and care.

For high carbon steel knife care kits, click here.