How to Clean a Carbon Steel Knife: Care & Maintenance Tips

Posted by Tara Hohenberger on

How to Clean a Carbon Steel Knife 

Carbon steel knives are loved by chefs due to their unique qualities, the most celebrated being their strength, ability to get sharp and ease of re-sharpening. This makes carbon steel knives a popular choice in professional kitchens.

Importance of proper maintenance - Once you try carbon steel blades, you’ll quickly understand that they differ from stainless steel blades. Maintenance is different, in that carbon steel blades need to be kept clean and dry in order to prevent oxidation and rust. Oxidation is the chemical reaction that causes rust. It’s also a good idea to keep a damp paper towel next to your cutting board , especially when cutting acidic foods.

The Distinction Between Carbon Steel and Stainless Steel

Composition of carbon steel. Carbon steel is made from iron, mixed with other elements. Different elements will give different characteristics and produce a different kind of steel. An alloy is a metallic substance formed by 2 (or more) elements..

Why does carbon steel require more care? The main reason is that it is reactive, which means that the surface metals undergo chemical reactions when they come in contact with certain ingredients.

What about chromium content and oxidation?
Steel blends that contain chromium usually have stainless properties. This is because the chromium in the steel reacts with oxygen to produce a layer of chromium oxide. This layer is very thin, but provides protection from corrosion.

The Patina Phenomenon: A Natural Armor

What is patina? Patina is a coating that occurs when metal is left exposed to the elements. You might notice a blue or gray appearance on the surface of the chef knife. This is caused by the surface metal reacting to the ambient air or moisture and a chemical compound forms.

It’s not uncommon to see a patina on traditional Japanese steels. They take on a patina when they oxidize due to their low chromium content. Patina is desirable because it is a natural protective. Patina can come in different colors and will evolve with time, but red rust should always be removed.

How patina protects your blade. The layer formed by patina is like a protective barrier that stands in the way of further oxidation. Continue to keep the blade clean and dry, as the presence of patina will not completely prevent rust.

The role of acidic foods in patina formation. Commonly used produce like onions, tomatoes and citrus have varying degrees of pH that can react with the steel on a knife blade. Leaving a residue on the blade for an extended period of time can speed up patina formation. There are several tutorials on how to force a patina using vinegar or mustard. While there are several routes to take, a patina will form naturally from using your knife.

Essential Carbon Steel Knife Care

Cleaning - We often get asked, "Should carbon steel knives be washed?" Absolutely yes, we recommend using warm soapy water.  Rinse well and dry immediately with a soft cloth.  Having drops of water sitting on the blade will lead to quicker oxidization and should be avoided. Some cooks use a damp cloth to wipe the blade in between cuts.  Avoid harsh cleaning solutions and never put quality knives in the dishwasher.

Proper knife storage:

It’s important to protect your knife blades. Wooden sheaths, known as sayas are a great option to protect your knives, whether you are storing them in a drawer or knife bag on the go. Wood is a great choice when covering a blade because it wicks away moisture and doesn’t let it collect on the blade. Similarly, look for wood construction when choosing a knife block.

Should You Oil Your Carbon Steel Knife 

A high quality knife oil can be a good option if you live near the sea or in a very humid environment. The use of a food-grade mineral oil - creates a moisture proof and oxidization proof barrier to protect the blade. We recommend this knife oil made from Japanese Camellia specifically for carbon steel knives. If your knife is used infrequently, it’s a good idea to oil it before storage.

Frequency of oiling - How often you oil really depends on how much you use the knife and the environmental conditions where you live. If you keep you blades very clean adn dry and notice excessive oxidation, using knife oil is probably a good idea.

Step-by-Step Guide to Cleaning Carbon Steel Knives

Removal of tough rust spots
You can use Barkeepers Friend or baking soda with a little lemon juice to dissolve rust build up.

A rust eraser is an abrasive tool that works great on red rust.

Avoid using steel wool, because it can scratch and remove intentional finishes like kurouchi.

Discoloration can often be addressed with white vinegar on a soft cloth. Apply softly until you get the desired result. Then wash and dry well.

For more tips on rust removal visit our blog.

How to Polish Carbon Steel

How to Polish Carbon Steel
You can polish carbon steel with an abrasive material. Fine fine-grit whetstones work very well, leather stropping belts, metal polishing compounds or polishing wheels also will accomplish the job. Keep the grit in mind, as rougher grits can produce unwanted scratches.

Advanced Care Techniques

Polishing carbon steel for a sharp edge is really no different than other knives. Use whetstones and follow the general guidelines to remove the burr.

Honing rods can realign an edge, but has its limitations on truly restoring a cutting surface. To sharpen, steel needs to be removed using a sharpening stone.

Conclusion

High carbon steel knives offer tremendous performance, sharpness and durability when properly maintained. It’s the reason why they are so popular in professional kitchens. They can last a life time when given proper care and attention. Keep the following care points in mind and reap the benefits of carbon steel knife performing at its peak.

Wash with soapy water and dry immediately after use.

Keep a damp, soft cloth on hand to wipe the sides of the blade in between cuts when working with very reactive ingredients.

Remove rust promptly with a rust eraser.

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