5 Signs Your Kitchen Knife Needs Sharpening

Even the finest chef knives — including high-quality Japanese blades — will lose their edge over time. Daily chopping, slicing, and dicing slowly wear down the blade’s microscopic sharp edge. A dull knife doesn’t just slow you down in the kitchen; it can also be more dangerous, as it requires more force and increases the risk of slipping.

So how can you tell if it’s time to sharpen your kitchen knife? Here are five clear warning signs that your blade needs attention.

1️⃣ It Struggles to Cut Through Tomatoes

Tomatoes are the ultimate sharpness test. Their soft flesh and thin skin demand precision. If your knife crushes, squashes, or tears a tomato instead of slicing cleanly through, your blade’s edge is no longer at peak performance.

Why it matters: A sharp knife should be able to cut a ripe tomato with almost no pressure. Struggling here is a sure sign it’s time for maintenance.

2️⃣ You Need More Force Than Usual

Sharp knives let you work with minimal effort, relying on the blade’s keen edge rather than your strength. If you notice you’re pressing harder or sawing back and forth to make a cut, your knife is doing less of the work — and you’re doing more.

Why it matters: Excess force not only tires you out but can also cause the knife to slip, making accidents more likely.

3️⃣ Food Slips While You’re Cutting

A sharp blade “bites” into the surface of the food, holding it steady. When your knife slides off an onion, rolls over a carrot, or skates across meat, it’s because the edge is too dull to grip the surface.

Why it matters: Slippage is one of the top causes of kitchen injuries. Maintaining sharpness is essential for safety.

4️⃣ Uneven or Ragged Cuts

Clean, even slices are the mark of a professional kitchen. When you see frayed herb edges, jagged vegetable cuts, or meat with torn fibers, it means the blade is crushing rather than slicing through food.

Why it matters: Dull knives can damage the texture of delicate foods, affecting both presentation and flavor.

5️⃣ It Fails the Paper Test

The paper test is a simple, at-home way to check sharpness. Hold a sheet of paper upright and try slicing from top to bottom. A sharp knife should cut cleanly in one smooth motion. If it snags, tears, or refuses to cut, it’s time to reach for the whetstone.

Why it matters: This test is quick, repeatable, and works for all types of kitchen knives.

⚠ Why Sharp Knives Are Safer

It may sound counterintuitive, but sharp knives are actually safer than dull ones. A dull blade requires more force, which increases the chance of losing control. Sharp knives let you work efficiently and with less risk of injury.

🔧 How to Prevent Your Knife from Getting Dull Too Quickly

• Use a wooden or plastic cutting board — avoid glass or ceramic boards, which dull blades quickly.
• Hand-wash your knives immediately after use and dry them thoroughly.
• Store knives properly in a block, magnetic strip, or knife guard.
• Hone your knife regularly to maintain the edge between sharpening sessions.

💡 OSERM Pro Tip

Don’t wait until your knife is completely blunt. Regular light maintenance — a few passes on a honing rod every week — will keep your blade sharp and ready for any cooking task.

🎁 Special Offer

This week only: 30% OFF all OSERM Chef Knives + FREE U.S. shipping.
👉 Shop Now

Tags: signs dull kitchen knife, when to sharpen knife, how to tell if knife is dull, knife sharpening tips, OSERM knives