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How to Correctly Remove Rust from a Japanese Chef Knife

 

A Japanese chef knife is something that many consider a work of art. They are designed through years of mastery and have the intention of appealing to all five of the human senses.

They are not only designed to be functional but also a joy to use and own and therefore a certain level of pride should be taken for the maintenance of these kitchen staples. 

Regular sharpening, polishing, and proper cleaning should be common practice however, there are times when the knife can be neglected and this can eventually lead to rust. 

Not only is rust unsightly but it also makes your knife unusable (rust should not be coming into contact with food) and therefore it’s important to know how to remove rust and restore these knives to pristine conditions. 

To correctly remove rust from a Japanese chef knife, you should let it sit in a solution of white vinegar or a baking soda paste for 5 - 10 minutes, after which you should wipe down the rusted areas with a cloth or sponge and use steel wool if needed for particularly rusted areas.

You can also use more manual methods to remove rust such as scrubbing it with a rust eraser or on a sharpening stone. 

Rust removal from a Japanese chef knife can be a relatively quick and effortless task, depending on how much rust has formed on the blade.

In this article, we are going to cover some of the most common ways to remove rust from a knife and help you to prevent it from forming again in the future. 

Table of content

Why do Knives Rust?

When it comes to knife care, prevention is always the best option over correction when it comes to rust. To know how to prevent a knife from rusting, it’s important to know why your knives can rust when subjected to certain environments. 

You might also be thinking “well, I have a stainless steel knife so this surely doesn’t apply to me?”. Unfortunately, a stainless steel knife is only stain-less and not stain-free and therefore unless you have a ceramic knife, your still blade will be susceptible to rust. 

Rust, the orange flakey and gritty material that you might find on metal, is the outcome of a chemical reaction known as iron oxidation. This is the process whereby iron reacts with air and water to form what is more commonly known as rust. 

A steel knife is formed from iron and therefore anytime your knife is subjected to water and air for a prolonged period of time it will become susceptible to rust.

This process is not instantaneous, however, if you leave water on a knife for a long enough period then you will eventually see rust start to form and yes, this is even true for stainless steel knives. 

How to Correctly Remove Rust from a Japanese Chef Knife

When it comes to removing rust from a Japanese knife, there are a few options available to you, and these range from standard home remedies to specially made rust removers. In this section, we are going to run through some of the best ways that you can remove rust from your knife. 

In our opinion, there is not one single best method for removing rust from a Japanese knife, and the method you choose will depend on how bad the rust actually is. 

The key thing that we want to point out is that you shouldn’t use a chemical cleaning solution to try and remove the rust, as this can be detrimental to knife health as well as the potential to contaminate any food that you prepare after use. 

Note - you can also use a combination of these methods depending on how much rust is on the knife. 

White Vinegar Solution

 

White vinegar (or apple cider vinegar) is the most popular and easiest form of rust removal for a slightly rusted knife. It will work with heavily rusted knives but it may require multiple applications to break down more substantial levels of rust. 

Simply submerge the blade of your knife in white vinegar (some recommend warm white vinegar) into a tall glass or plastic cup for 5 minutes. The acetic acid will attach the rust and start to break it down, just ensure that if you have a wooden handle on your knife you only submerge the blade into the vinegar. 

After 5 minutes wipe down the blade with a cloth, sponge, toothbrush, or steel wool to easily remove the rust from the blade. Rinse again and then dry the blade. 

Baking Soda

 

Baking soda uses a similar approach to the white vinegar, mix baking soda with water to form a paste, and apply this to the knife blade in the areas affected by rust. Leave the knife to sit on a kitchen towel for up to an hour and then scrub the knife with a toothbrush or steel wool and finally rinse the knife clean. 

If there are some persistent areas of rust, use the same paste and apply it to the toothbrush to then scrub these stubborn areas. Rinse the knife clean and dry it for a smooth finish.  

Rust Eraser

 

A rust eraser is a popular product that can be used to remove small levels or rust and can be used effectively in conjunction with a sharpening stone. These rust erasers are essentially small sharpening stones with varying grades of grit that will remove rust with a more manual, ‘elbow grease’ approach. 

These are perfect for getting into awkward areas like the spine or edge of the blade and a fine grit of around 1000 - 3000 grade will be ideal for tackling hard to remove rust. 

For this method, you can again use the white vinegar solution to either soak or coat the knife, leave it for a few minutes to activate, and then scrub the blade with the rust eraser. This combination in our opinion is the most effective for rust removal and we’ve included a video further down in this article to demonstrate how effective this approach can be. 

Sharpening Stone

 

Using a sharpening stone is arguably the most efficient way to remove rust from a knife however this is also the most abrasive and requires a much higher level of skill and knife control. 

A sharpening stone is used to remove layers of steel to form an edge typically and therefore it can perform a similar function when you are looking to remove layers of rust.

This method is best for blades that have rust forming around the edge of the blade as the process is similar to simply sharpening your knife on the whetstone. 

If however, the rust is formed around the spine or either side of the knife then this can be much trickier to remove using a sharpening stone, and in these situations, we’d recommend using a solution above with a sponge or steel wool to remove rust from these more awkward areas. 

Re-sharpen the Blade

 

Regardless of which step you take from the above, it’s worth noting that after any sort of rust removal you will then need to resharpen the knife-edge afterward. This is because some of these rust removal techniques can be quite abrasive and your knife edge will likely become dull in the process. 

Therefore, an important part of the rust removal process will always be to sharpen your knife as the final step to reform the edge and ensure that it’s in optimal working condition.

Final Thoughts

Whether you have neglected your knives slightly and allowed some rust to build up or you’ve come across a bargain-priced knife that could be a premium tool once cleaned up, it’s good to note that rust removal is quick and easy. 

If you follow some of the steps we laid out above, rust removal can take as little as 10 minutes (depending on how bad it is), and will see your blade looking brand new. Just make sure that once the rust is correctly removed that you then follow some basic maintenance steps to prevent rust in the future. 

These steps include regular honing and sharpening of the edge, ensuring you hand dry the knife after cleaning so that it doesn’t air dry, and finally storing the knife in a dry environment that’s free from moisture. 




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