This is why a honing steel won’t sharpen a dull knife—and what you need instead

Hardly any knife block comes without one: the long rod that cooks swipe their blade along before chopping or carving. Plenty of home cooks do the same, giving the knife a few strokes before getting on with dinner. And for a while, it seems to work.

Then the tomato skin starts folding under the blade. An onion that used to slice cleanly begins sliding around the cutting board. You run the knife over the rod again, but it still doesn't cut properly. Which probably has you wondering if you’re doing something wrong.

Fortunately, the answer comes down to the difference between honing and sharpening.

Two tools, two different jobs

A honing steel realigns the knife's existing edge. With everyday use, the edge can become misaligned even though there is still plenty of usable metal there. Running the blade along the steel brings that edge back into alignment.

Sharpening is different. A whetstone removes a small amount of metal to reshape the edge and create a new cutting surface. That's what a genuinely dull knife needs. 

There are exceptions. Diamond-coated rods are abrasive and can remove metal, so they're not the same as a traditional honing steel. If you have an expensive or Japanese knife, check the manufacturer's care instructions before choosing a rod.

The tomato test tells you when to stop

Take a ripe tomato and gently draw the knife across the skin. A sharp knife should bite into the skin without needing much downward pressure.

If the blade slides across the tomato or squashes it before cutting through, another round with the honing steel probably won't help. Made In recommends the tomato test as a simple way to check whether a blade needs sharpening.

That's when you need a whetstone, another sharpening method or a professional sharpening service.

How to use the honing steel

Place the tip of the steel on a stable, non-slip surface. Hold the knife against it at roughly 15 to 20 degrees, then sweep the blade down the length of the steel.

Made In's guide recommends about five strokes on each side, although other knife specialists suggest more. Use light pressure and keep the angle consistent.

If the knife still doesn't cut properly afterwards, it's time to sharpen rather than keep honing.

A whetstone takes more practice

A whetstone gives you more control, but the technique takes practice. Secure the stone on a stable surface and keep the blade at a consistent angle as you work.

Many kitchen knives use an angle around 15 to 20 degrees per side, but this varies between knives. Follow the manufacturer's instructions where available. King of Knives gives the same general range.

If you're worried about damaging an expensive or thin Japanese knife, a professional sharpening service is another option.

A dull knife is also a safety problem

A blunt knife isn't just frustrating. It can also be more dangerous.

According to NC State Extension, a dull knife requires more force to cut and is more likely to slip.

So the rule is simple: hone to maintain the edge, sharpen when honing no longer brings it back.

Once the knife is sharp again, wash it by hand, dry it properly and store it in a block, on a magnetic strip or with a blade guard rather than loose in a drawer.