How to Know if Your Knives are Sharpened Correctly: A Guide for Professionals and Enthusiasts

Introduction

Sharpening a knife is an essential skill that can enhance its performance and longevity. However, knowing whether a knife has been sharpened correctly can be a bit challenging. This article will guide you through various methods and tests to determine if your knives are sharp and properly maintained.

Common Methods to Test Knife Sharpness

Tomato Test

One of the simplest and most widely-known methods to test knife sharpness is the tomato test. Here are the steps:

Chosen a very ripe or even slightly overripe tomato. Place it on a cutting board. Hold the knife blade lightly on the tomato, attaching it with just two or three fingertips on the handle. Drag the blade back across the tomato slightly to see if it cuts through cleanly. If the knife easily slices through most or all of the tomato, it is considered to be very sharp.

Viewing the Blade Edge

An alternative method involves holding the blade correctly to examine its edge:

Hold the knife in a way that the spine (backside) is down and the edge is up. The tip should be away from you. Hold the knife and rock it slightly back and forth to see the light glint off the edge. Look for a straight and smooth edge. An irregular or wavy edge indicates poor sharpening. Absolutely avoid flat spots on the edge, as they will catch the light and reflect it.

My Three Basic Tests

As an experienced knife sharpener, I follow these three basic tests to ensure maximum sharpness:

Arm Hair Test: If a knife can shave the hair on your arm, it is considered sharp. Fingernail Test: Place the knife on your fingernail and press slightly. The knife should biting in and not moving. Paper Test: Check if the knife can cut paper cleanly without tearing. Tomato Test: As mentioned earlier, a knife should cut a tomato cleanly with no tears.

It's important to check at least three places on the edge, as sharpness can vary. The ideal angle for the blade's edge is between 15 to 20 degrees on each side. When sharpening, hold the knife at about a 15-degree angle to the whetstone. Run it a few times on each side on a piece of steel for finishing. Some prefer using a leather strop for final polishing.

Understanding the Types of Knife Edges

Sharpening a knife is not only about making it sharp; it also depends on the specific type of knife and its intended use. Consider the following angles and types of edges for different knives:

Chopper (Butter Knife): An oblique angle, typically around 50 to 60 degrees. Egg Slicer (Slicer): Ideal for delicate cuts, around 100 to 120 degrees. Dinner Knife: A balanced angle, somewhere in between the chopper and slicer.

However, the absolute best edge for a blade is a 160-degree polished edge, similar to the way a samurai sword is sharpened. This edge is created by polishing the entire bevel, not just the last millimeter. This type of edge provides the longest-lasting and sharpest blade.

Conclusion

In summary, knowing the correct way to test and maintain your knife's sharpness is crucial for professional chefs and knife enthusiasts alike. By following these methods and understanding the right angles and types of edges, you can ensure your knives remain in peak condition.