Why High-Carbon Steel Rusts (And How to Stop It)

Why High-Carbon Steel Rusts (And How to Stop It)

High-carbon steel knives are loved for their sharpness, precision, and performance — but they need a little more care than stainless steel. If you’ve noticed rust spots on your blade, don’t panic. Here’s why it happens and how to protect your investment.

⚙️ Why High-Carbon Steel Rusts

1. Lack of Chromium

Unlike stainless steel, high-carbon steel doesn’t have enough chromium to form a protective barrier. Chromium creates a thin chromium oxide layer on stainless steel, which blocks rust — high-carbon steel doesn’t have this.

2. It’s More Reactive

High-carbon steel reacts easily with oxygen, moisture, and acids — all things you’ll find in any busy kitchen. That reaction is what causes oxidation (aka rust).

3. Environmental Exposure

In Kenya, coastal areas with salt air (like Mombasa) or humid kitchens can speed up rusting. Acidic foods like lemons, tomatoes, and onions also increase the risk.

🛡️ How to Prevent Rust

✅ Keep It Dry

Always dry your knife with a soft towel immediately after washing. Water left on the blade is your #1 rust culprit.

✅ Oil the Blade

Use a few drops of food-safe mineral oil, camellia oil, or even cooking oil to lightly coat the blade after cleaning. It forms a barrier against moisture.

✅ Avoid the Dishwasher

Dishwashers expose knives to high heat, water, and salt — all enemies of carbon steel. Always hand wash.

✅ Store It Right

Keep your knife in a dry, ventilated place. Use a magnetic strip, knife block, or breathable sheath — not a drawer where moisture can build.

✅ Oil the Handle Too

Wooden handles can dry out and crack. Wipe them with a food-safe oil occasionally to keep them sealed and strong.

🧽 What To Do If Rust Appears

🔸 Light Rust?

No problem. Use:

  • A rust eraser
  • Fine steel wool
  • Wet/dry emery paper

Rub gently in one direction, clean off the residue, then oil the blade.

🛠️ Need Help Restoring a Rusted Knife?

We offer professional sharpening and rust removal services at KISU KENYA.

📍 Available in Mombasa or nationwide via courier
📞 WhatsApp us: +254791717333
🛒 Or visit our Sharpening & Repair page to learn more

📚 Want to Learn More?

Check out our other blog post:
👉 High Carbon vs. Stainless Steel Knives: What’s Best for Your Kitchen?

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