The Foolproof Test To Tell If Your Knife Has Gone Dull

You wouldn't immediately think it, but a dull knife is far more dangerous than a sharp one. Imagine the frustration of trying to slice a tomato for a nostalgic tomato sandwich, only to squash it into a pulpy mess — and possibly end up with a nicked finger. It's a clear reminder that even your best chef's knife needs regular maintenance to stay sharp. But, how can you tell if it's time for a tune-up?

The thumb test, where you lightly run your thumb across the blade to gauge sharpness, is a well-known trick, but it's not always reliable — and fingers and blades aren't the safest combo. For a safer and more effective method, turn to the paper test.

For the paper test, grab a regular sheet of printer paper, a glossy magazine page, or even a newspaper sheet — anything thin enough to cut cleanly. Hold the paper lightly by the edge so it hangs freely. Start with the part of the knife closest to the handle, called the heel, at the top of the paper. As you slice downward, pull the knife slightly toward yourself, moving the blade across the paper so the cut begins with the heel and finishes at the pointed tip. 

If the knife glides through cleanly without snagging, your blade is sharp and ready for action. But if it struggles, tears the paper, or doesn't cut through smoothly, your knife has dulled and needs a little TLC.

Once you've confirmed your knife has dulled, it's time to restore its edge. A whetstone is a classic and highly effective method. Start by soaking the stone in water for 15 to 20 minutes to lubricate the surface for smooth sharpening. Place the stone on a stable base, hold the knife at a slight angle (about 20 degrees), and slide the blade across the stone in smooth strokes, starting from the heel and moving toward the tip. Repeat this motion on both sides of the blade using the coarse side of the stone to reshape the edge.

Whetstones often have one side with a coarse grit for heavy sharpening and another with a finer grit for honing and polishing. After working with the coarse side, flip the stone to the finer side and repeat the same process. This second step smooths and refines the blade, leaving it polished and razor-sharp. With just a little time and effort, your knife will be slicing effortlessly again.

Alternatively, many people prefer knife sharpeners for their convenience and ease of use. The Orange Ninja model, available on Amazon for $18.39, features an ergonomic handle, a non-slip rubber base, and multiple sharpening stages for coarse, medium, and fine adjustments. With its straightforward design, it takes the guesswork out of sharpening. Whether you choose a whetstone or a sharpener, maintaining a sharp blade ensures you can safely slice through multiple tomatoes at once, making sandwich prep a breeze.