The Essential Guide to Testing Your Knife Sharpness

Digging into knife sharpness: a razor sharp knife is the unsung hero of the culinary world and an indispensable tool for crafters, survivalists, and everyday carry (EDC) aficionados.

But what good is a knife if it's not sharp?

The simple answer—none.

Yet, many knife owners struggle with defining and maintaining the sharpness of their blades. Testing the sharpness of your knife is not only a matter of convenience and safety—dull knives can be more dangerous than their sharp counterparts.

This guide aims to demystify the process of testing knife sharpness, equipping you with the know-how and confidence to keep your blades in primo cutting condition.

Understanding the Importance of a Sharp Knife

Before we get into the nitty-gritty of testing, it's crucial to understand why knife sharpness is non-negotiable. A sharp knife:

• Cuts with ease, reducing the effort needed to slice through various materials. The sharper the edge the less downward pressure you need to cleanly cut through.
• Provides a more exact cut, valuable for delicate operations like filleting fish or surgical procedures. Want an easy way to level up the presentation of you next meal? Having an exact cut can quickly take your presentation into WOW territory.
• Poses a lower risk of slipping and causing injury, as it requires less pressure to cut. As you push down harder and harder, the more likely the knife is to roll and cause harm to you.
• Maintains the integrity of the material being cut, particularly critical in cooking to preserve texture, taste, and presentation. Nobody likes being served a squashed tomato...

Tip: The key is to remember that sharpening isn't just about the edge; it's about the entire bevel being uniform and the apex being dense enough to cut efficiently.

Signs of a Dull Knife

Recognizing a dull knife is the first step to preventing mishaps.

Common indicators of dullness include:

• Increased effort required to cut through materials. Does slicing through onions feel like its taking more effort than normal? Is cutting that paracord feel like you're cutting with a spoon? If so, you might have a problem.
• Ripping or tearing rather than cleanly slicing. If you cut open the tape on a box and it the tape looks like you tore through it with your keys then you might have burrs or chips causing problems.
• Not holding an edge or losing sharpness quickly after sharpening. This could be a sign of a soft metal or it could still be dull.

If you notice these signs, it's time to test the sharpness and potentially take action to restore your knife's edge.

Ok. Before we get any further, we recommend ALWAYS using proper safety equipment to protect yourself when handling knives. If you don't feel comfortable safely performing the tests listed or discussed below take your knife to a local professional who can help you diagnose problems and care for your knife.

Methods for Testing Knife Sharpness

There are several methods to test the sharpness of your knife.

Before you get into testing, a visual inspection of the knife edge should be your first stop. Many times you can see where problems are originating with the naked eye. We recommend taking a blank sheet of paper and laying it on a counter then lay your knife against the paper. This way you can see any chips or problems.

Each of these methods serves a different purpose and can work well in various situations. Make sure when you test, that you use the entire length of the knife. Here are the most widely used approaches.

The Paper Test

The paper test is a simple and commonly used method to evaluate any knife's sharpness. Take a blank page in one hand and try to slice the paper cleanly when you hold the knife in your dominant hand.

A fully sharpened knife will cut through without snagging without much effort, while a dull one may tear the paper. If you find a jagged cut you may have burr issues or breaks in the edge.

The Tomato Test

Considered a more practical test for kitchen knives, the tomato test involves attempting to make thin, clean slices of a ripe tomato.

To perform the test, place a tomato on your cutting board on a flattened end. Take your knife and attempt to slice through the tomato. A sharp knife should glide through the skin and soft flesh with little resistance.

The Arm Hair Test

For those who want to get a tactile sense of sharpness, the arm hair test is an effective (and slightly adventurous) method. This test is typically used for finer or thinner edges like Japanese chef' knives or straight razors.

This test involves taking your knife in your dominant hand. Then perform a shaving test on your opposite arm. A sharp knife will shave hair off cleanly and with ease.

Note: the shaving test is one of the more dangerous tests. only do this test if you can do so safely, and don't mind losing a little hair.

The Bond Paper Test

This test involves cutting lightweight bond paper (we use receipts). A sharp knife will cut through paper effortlessly, while a dull knife may crumple or tear the paper instead.

The testing method is very similar to the paper test described earlier.

Now What?

Ok, you performed a sharpness test and found your knife isn't as sharp as you want. Now we have to get your knife back to a cutting edge.

Sharpening Strategies

Theoretically, the edge of a knife is the intersection of two perfectly flat surfaces creating a perfectly straight line. The sharpening process is essentially that of removing metal from the edge to achieve a consistent geometry.

²George Williams

Keep in mind that there is no one-size-fits-all approach to knife sharpening. The best method for sharpening your knives depends on the type of blade (hardness), the style of the edge(straight, serrated, convex, etc), and the level of dullness.

Real quick: its worth mentioning two terms. Honing and Sharpening.

Honing vs. Sharpening

These terms are often used interchangeably, but they have different purposes.

Honing is about straightening the edge of a sharp knife. When you hone an edge using a strop or honing rod you are bending the very edge back into proper alignment. No material is removed because the knife's edge is already making a clean cut.

Sharpening involves grinding the edge to create a new bevel to restore the hard V shape at the edge.

How do you know if you need one or the other? Here's a quick way we use. Taking your tomato from before still on the cutting board. If you roll your wrist slightly one way or the other cause it to cut better? If so, honing is in your future.

When it comes to sharpening here are some common strategies:

DIY Sharpening

If you're comfortable with a DIY approach, handheld sharpeners or whetstones can be effective. However, it's crucial to follow proper techniques to avoid damaging the blade.

We recommend a system that holds your knife for you with a handle that keeps your finger s and the heel of your hand free from being cut.

Professional Sharpening

For those less confident in their sharpening skills, professional sharpening services can provide a safe and precise edge. If you're looking for a pro to help you reach out to your local knife shop. They can usually point you in the right direction if they can't handle it themselves.

Knife Sharpening Dos/ Don'ts

Maintaining a knife is an art as much as it is a science. Here are some crucial dos and don'ts to keep in mind:

• Do learn the proper angle for sharpening your specific type of knife.
• Do use a lubricant when sharpening to prevent overheating and the loss of temper in the blade.
• Do sharpen steadily and consistently to achieve a smooth, even bevel.

 

• Don't rush the sharpening process; patience is critical for a quality edge.
• Don't forget to clean and dry your knives after sharpening to prevent rusting and other damage.
• Don't use the wrong tool for your knife, as this can lead to ineffective sharpening or damage.

Advanced Knife Sharpening

For those looking to take their knife care to the next level, here are a few advanced tips:

• Understand the difference between sharpening angles for various tasks (heavy-duty tasks often call for a wider bevel).
• Explore abrasive compounds and strops during honing for a polished, razor-sharp edge.

The Cutting Edge of Knife Care

Knowing how to test your knife's sharpness is a fundamental skill for any knife owner. By familiarizing yourself with the methods mentioned here, practicing safe sharpening techniques, and incorporating regular maintenance into your knife care routine, you'll be well on your way to a blade that is not only sharp but one that perfects the art of cutting.

Remember, a sharp knife not only makes your tasks easier and safer but also elevates your craft, be it in the kitchen or the great outdoors. Happy sharpening!