If you’re invested in a nice knife, you’ve more than likely had a run-in with a patina. It’s basically unavoidable, to some extent, but you might not be sure whether you should be alarmed or not when it develops. A patina is a form of oxidation, like rust, but does that mean you’ve ruined your knife? Or does a patina actually protect your steel?
A patina formed on steel does help to prevent rust from forming on a steel blade. While they are both forms of oxidation, rust will eat into the edge and cause damage to the metal, whereas a patina will form a sort of finished seal that can prevent corrosion and future rust damage. A patina works by leaving no desirable area on the blade for rust to form.
So, there you have it. If you were worried that a patina is going to ruin your knife, fret no more. Developing a nice patina on a carbon steel blade is something you should do to protect your trade’s unique tools. So, to learn more about the benefits of a patina and how you can get your own started, read on.
How Does A Patina Form?
Just as cast iron needs to be seasoned to be at its best, so too does a carbon steel knife. A patina is a type of aging that happens naturally to carbon steel and stainless steel to some extent. It is less likely to form on stainless steel due to the presence of chromium.
Without chromium, carbon steel is left more vulnerable to corrosions, like oxidation that can eat into the metal and eventually ruin your blade. Thankfully, there is a way to protect your steel, and you guessed it: a patina.
When moisture and oxygen make contact with carbon steel, you get oxidation. When you keep a blade clean and dry, you get smaller amounts of oxidation, which allows for magnetite production. Essentially, a patina can have a wide variety of minerals and chemicals in its makeup, but magnetite is one of the most common types of beneficial oxidation in these circumstances.
Get enough magnetite that you start to see staining and coloring in the black/gray spectrum, and you’ve got yourself a developing patina. If you start to develop red/orange, flaky spots of discoloration, you’ve got rust, not a patina. Basically, a patina is rewarded naturally when you take good care of a knife. Rust is the punishment you receive from treating a knife poorly.
Why Is A Patina Beneficial?
Carbon steel is already a better choice for a knife over stainless, but the patina takes it a step further. How exactly does a patina make a good knife better?
- A Patina Seals Your Steel: A thin layer of patina can prevent rust from forming. Rust is the enemy, and a patina is its worst nightmare.
- It Makes Your Blade Last Longer: Since a patina prevents further corrosion, your blade is likely to last a lifetime or beyond. Since no other oxidation can occur, the patina effectively forms a seal around your knife.
- It Lets You Be Lazy: The longer your patina has developed, the more effective it will be to prevent rust when exposed to moisture. Meaning, if you leave it on the countertop, still wet, you don’t have to worry as much about your knife gathering rust. You still need to wash it, though.
- They Look Great: Knife nerds and commoners alike both agree, a patina looks impressive. Much like the wear on leather, or the fade on old denim, a patina is aging done right. Some manufacturers go out of their way to force a patina, while others are left to time.
Do I Need to Have A Patina?
To have a patina, or not to have a patina? It’s actually up to personal preference. While it is undoubtedly beneficial in the long run, some knife-wielders just aren’t fans of this helpful corrosion. They may not like the overall appearance of a worn-looking blade with asymmetrical black and gray staining. Some of us just enjoy the glint of polished steel with nothing to mar that shine.
On some knives, the patina can change how the blade feels as it moves through the material it is cutting. Although a patina is relatively smooth, its surface is not always as uniform as the steel itself. It can make a blade drag through material like softer meat or vegetables, and a perfectionist chef may want something that lends more precision.
Of course, if you are to avoid a patina from forming, you need to be diligent about cleaning, drying, and storing your blade. There is absolutely nothing wrong with preventing corrosion. If you are looking for a little protective insurance on your knife, the patina is a simple way to get that extra protection. And we all know, many of us aren’t going to take the time to clean our knives right away after every single use. A patina can give a bit of a buffer during these short periods of negligence.
Forced Patina or Natural, Which Is Better?
Again, it mostly comes up to preference. All patinas do the same thing, form a seal to protect steel from further corrosion. Still, there are some different methods for developing a patina on a knife.
You can force a patina to form more quickly on a knife. The results are varied, but it can be a fun experience to see what develops. Here’s how.
- Clean the blade well: Any grime or stains could be set in or mess with the build-up of your patina.
- Apply Mustard to The Blade: Yes, mustard. Patinas form best when high acidity is involved, and a mild acidic paste, like mustard, is cheap and convenient. All you need is a thin coat.
- Make Some Designs: By moving the mustard around with your finger, a brush, or a toothpick, you can get some cool designs as the corrosion appears. Or leave it alone and let it do its thing.
- Wait About 15 Minutes: The acid works quickly, eating into the top layer of steel and allowing the patina to form.
- Rinse and Dry: Clean off the mustard with water, wiping with a cloth to get any stuck-on condiment, and dry the knife completely. Since you’ve opened up the steel, moisture can cause rust just before a patina sets.
- Wait: With the knife dry, a patina should begin to develop. It will also grow stronger over time and with use.
A natural patina can be more subtle and timeless, though it protects just the same. A natural patina will form over time as the blade is introduced to salt, acid, water, and wear. It’s all relatively easy. If you aren’t afraid to develop a natural patina, do the following:
- Use Your Knife: Regular wear will make the patina set uniquely, based on how you use your knife and the different metals involved in construction.
- Keep It Clean and Dry: Don’t try to build a natural patina by neglecting your knife on purpose. This will more than likely leave you with a rusty, gross blade.
And that is all there is to it. As long as you don’t let rust set in, your carbon steel knife will likely develop its patina over time and with use. Don’t rush it, and you’ll be fine. And, if you don’t like it in the end, you can always polish it back to normal.
So, we’ve told you the secrets of patina, the beneficial form of oxidation that can make your blade last longer and look better. Hopefully, this has answered your questions about this mystical corrosion, and you can decide whether it’s right for you and your blades or not.