How to Sharpen Your Knife

Published on 02/24/2023 · 14 min readCutlery Expert Andrew Forrest details the ins and outs of when and why you should sharpen your knives as well as the different options of how to sharpen them!
Andrew F, Kitchen Expert
By Kitchen Expert Andrew F

Hello to the new chefs, home cooks, and other kitchen knife enthusiasts hoping to get an understanding of the basics of how to get a sharp knife through a variety of methods! To start with, let’s answer a key question…

Why Should You Sharpen Your Knife?

A sharp knife is a safe knife! A dull blade will increase the risk of painful slips and accidents. Cutting your vegetables and meats with a high-quality sharpened blade will ensure the cooking process is done evenly, making your food taste even better. A knife edge should be smooth and sharp. Sharpening a knife regularly will create a healthy habit when taking care of your kitchen tools.

Now it’s time to break down how to do it. To keep this simple and straight to the point, I have divided this article into two parts. One is for the DIY-ers who want to learn how to sharpen their knives like professionals at home, and the other is for the high-quality kitchen knife users who plan on sending their knives to be sharpened professionally.

There are many benefits to sharpening your knives at home and understanding the quality of your tools. On the other hand, taking your knives in can help save storage space in smaller kitchens and allows for perfect results from the beginning. We will talk about how often and the best places to take your knives if you’re in this group!

Sharpening Knives At Home

In order to learn about sharpening knives, we need to get familiar with the knife itself. Let's take a look at the diagram below.

Above are the general parts of a knife. The knife edge is also called a blade edge. These can be used interchangeably. And yes, this is the sharp edge, so be careful when sharpening your own knives to avoid accidental cuts. It is also important to note that, although not mentioned above, the very bottom of the blade edge where it meets the bolster is called the heel of the knife. The tip of the knife is very important because it will dictate how the rest of the knife will perform once sharpened. The edge must be even from the tip to the heel.

The sharpening process can vary slightly depending on which at-home sharpening tools you use. When approaching sharpening, think about whether you are looking for something to help keep your knife sharp in between taking it to a professional or if you want to be able to take a completely dull knife and reshape the blade.

The same process and thought are applied to each method below. The most important step in all of the sharpening processes below is to maintain the correct angle for the knife that you have, this will keep an even bevel across both edges of the knife, and be patient. This last part also applies to experienced sharpeners. A rushed job can lead to a subpar final product.

1. Electric Sharpener

There are many different makes and models of electric knife sharpeners on the market, but they all work generally the same and operate with little skill or practice. Two abrasive pads spin on motorized wheels at a similar angle to the blade. To sharpen, you simply pull the knife gently through the slots in the sharpener while keeping a firm and secure grip to prevent slipping.

2. Manual Sharpener

Photo by Eduardo Froza

The simplest, easiest, and cheapest way to sharpen your knives at home is with a fixed-angle manual sharpener. Similar to the electric knife sharpener, it has abrasive materials angled relative to the angle of the blade. These sharpeners typically have a V-shaped notch to pull the knife through. The edge of the knife should be held firmly but not pressed down while the knife is pulled through the chamber with even pressure.

3. Water Stones / Whetstone

Photo by Didriks

The oldest and most effective way to sharpen a knife at home is by using a whetstone or sharpening stone. They are found in a range of coarseness to tackle everything from sharpening the dullest knives to perfecting and polishing the sharpest knives.

Generally, a two-sided stone will be all an at-home chef should need and will come with a coarse grit side for the initial sharpening and a fine grit side to smooth things out along the blade. Whetstones typically come with directions and normally need to be left soaking in either water or oil before sharpening.

If you know that you will be having frequent sharpening sessions, do buy the whetstones individually. One will be a fine grit stone and the other a coarse grit stone. This way you will always have an even working surface and a sharpening surface which can experience a bit of uneven wear.

Whetstones typically come with directions and normally need to be left soaking in water for about 15 minutes or until the air bubbles cease to be seen. Preferably soak the stones in the sink until you are ready to sharpen them to avoid spillages. If you are going the mineral oil route, simply rub some oil on the surface you wish to use. You CANNOT go back and forth on this, pick a type of lubricant substance and stick to it, otherwise, you will damage the stones. Using water will be less costly than mineral oil.

When purchasing a knife, the manufacturer's instructions should state the angle of the blade and whether it is asymmetrical (which is rare and only comes on certain Japanese blades). Normally, Western-style knives will have around a 20-degree angle whereas softer Japanese knives are sharper and angled more toward a 15-degree angle. Knowing your knife and the degrees of the blade will not only help with sharpening but will help you to understand how it cuts.

Using whetstones might seem like a lot of work and somewhat counterintuitive at times, luckily it is extremely difficult to mess up a knife on a whetstone.

The technique of using whetstones is fairly vague and can be adapted in a variety of ways. There are devices called angle guards that attach to the backside of the knife to set your knife at the proper height for sharpening. Some people also will use coins stacked beneath the blade to create the proper angle on the side of the blade. My favorite method when learning is to use a permanent marker along the edge of the blade, and when the mark begins to fade, you know you have the right angle for the job. Before starting to use a whetstone at home, place a damp towel underneath the stone on your counter. Change the side of the knife you are sharpening after taking the same number of strokes on each side for evenness.

In the tutorial video above, master sharpener Vincent from Korin in NYC, holds the knife at a 5-o'clock angle to the stone with the cutting edge facing away from himself, holding the handle with his dominant hand and the blade firmly with his non-dominant hand. His thumb is used to create the angle that the blade needs. He slowly pushes the blade away from himself with the knife angled against its tip. After you have pulled your knife across the stone at least five times, you should notice a burr that forms—that is how you know it is time to change sides. Once you have burred both sides, you should notice the knife is sharper. It is now time to repeat the process on either the finer side of the stone or on another finer stone, depending on your sharpening tools.

Be aware that the heel of the knife (this is the part of the blade the furthest away from the tip) also gets an even sharpening session in order to maintain a smooth edge along the blade of the knife. Use the spine of the knife as a guide to compare how even your knife's edge is.

Using a whetstone is not something that has to be done at a fast pace or with an unreasonable amount of pressure. Slowing down and understanding the blade angles and the softness of the steel will help know your knife.

  • Repetition and Time Commitment: Whetstones can take time to truly master—between finding the right knife angle and building confidence—but this time investment is well worth it. You will probably be cooking for the rest of your life, so you might as well know how to sharpen your tools properly when needed.
  • Money Savings: Paying for years of sharpening can add up and increase the monetary investment in your knife. By learning how to properly and safely sharpen knives at home, you will save time and money with a small investment in sharpening tools.

Taking Your Knives in to Be Sharpened

How Often You Should Sharpen Your Knives

Knowing the tools that build out your kitchen allows for a better relationship with food prep. Having sharp tools to get the job done properly allows you to enjoy the kitchen experience. When you begin to feel resistance or you feel you have to apply too much pressure to the knife, it is typically time to get it sharp again. Once I start dealing with troubling tomato skins, I know my knives have had enough and it's time to sharpen. Generally speaking, every three to four months seems to be perfect for most at-home chefs, depending on how much they cook.

Where to Go to Sharpen Your Knives

Everyone knows they can take knives into stores like Sur La Table or William Sonoma to get sharpened, but what I’ve found after tons of different experiences from expensive kitchen stores, farmer's markets, and local sharpeners, is that knife stores and trained sharpeners will sharpen your knife much better and with much more care than big kitchen stores. Knife sharpening costs around $5-10 dollars on the knife, but can sometimes vary based on the knife's dullness or if there is damage.

Why Go Professionally?

Tools for sharpening take up space, so if you are sharing a studio apartment with your partner and are hurting on cabinet space, I would recommend taking your knives in. It can also save tons of time and will be perfect immediately, unlike sharpening yourself where it takes time to practice.

Testing Your Knives Sharpness

The most accurate way to test the sharpness of your knife is by cutting ingredients you are familiar with.

Onions offer mild resistance but are the most used ingredient in any kitchen. Cutting through an onion can dictate the level of sharpness acquired. Alternatively, there is also a tomato test where a knife is gently rocked back and forth on a tomato with the most minimal pressure. If the knife is indeed extremely sharp, no further pressure will be needed to cut through it.

Another sharp test involves the fingernail test. Lightly run the edge of the knife across your fingernails. If the knife is sharp enough, it will not run smoothly across any nail. If otherwise, it needs some more work.

The magazine paper test works very similarly to the average paper test. However, given that magazines have a different texture they require an even sharper edge. This is not necessarily true or better than a standard piece of paper. There is also the phone book paper test. Once again clean cuts must be achieved when a blade is run through a sheet. Since a phone book sheet is so thin, only a very sharp knife could cut it effortlessly. However, no one really uses phone books anymore!

The simplest and easiest way to see if your knife is sharp enough is indeed the paper test. To see how little resistance is needed to slice through a piece of paper run the knife blade gently against the edge of the paper to see if it cuts with ease. You want a razor-sharp result that will yield a smooth and effortless cut.

Knife Maintenance

Honing

Using a honing steel is a simple way to keep a knife sharp and is done by gliding the knife at the blade's angle against either a diamond, ceramic or steel rod while pushing the blade back to the center. A honing steel is essentially a metal rod that has grooves that are very thin and placed very tightly next to one another going from the handle of the rod to the tip of it. As previously mentioned, there are a few variations to this standard honing tool.

I do recommend being cautious when using diamond rods as they can chip easily and damage your knife instead of bringing back its edge. As an additional tip on varieties of honing tools, a ceramic honing rod can also be categorized as a sharpening steel. The ceramic surface can at times be coarse enough to lightly grind down the knife, thus actually sharpening it.

It is an essential part of maintaining the longevity of the sharpness you either perfected or paid for. In my opinion, through years of sharpening and conducting maintenance on a sharp knife, I have liked my ceramic honing rod for my sharper Japanese knives while I prefer a steel honing rod for my German and French knives as their steel is much stronger and takes more effort to reshape. Alternatively, you can use a leather strop for honing your knives and adding a final polish to the edge.

Washing, Drying, and Storing

Washing your knives is extremely important! Typically, I will wipe my knife throughout prep and then do a final clean with soap and a sponge. These types of high-quality knives are not dishwasher safe.

Drying your knives is probably even more important than cleaning them—a wet knife is a dirty knife! Wiping them dry with a towel or soft cloth after a wash removes the risk of rust. Keep knives free of moisture and stored in a dry place to prevent rust, discoloration, and other contaminants.

Store knives in a knife block, knife sleeve, or Saya. Alternatively, there are also magnetic knife strips and boards that can save space and add some personality to your kitchen space.

Cutting Boards

Photo by CA Creative

Use wood or plastic cutting boards as they are softer and easier on your knives compared to granite, glass, or marble.

Knife Storage

Keeping knives sharp starts with proper storage. Blades are fragile, especially when in contact with other blades. Organization and edge and tip protection will be the most effective way to prevent chips or damaged edges.

  • Cover: Knife covers and Sayas can be used to protect knives' sharp blades from clanking around in the kitchen drawer.
  • Roll: Knife rolls are a great storage and transportation option for a small set of knives.
  • Bag: Knife bags come in tons of shapes, colors, and sizes to match individual quivers.
  • Magnetic Strip: Magnetic strips can be used along walls and in drawers to prevent knives from smashing into one another.
  • Block: Knife blocks are simple and effective, but do take up a lot of space on the countertop.

Obscure Sharpening Hacks

The most common ways to sharpen a knife have been listed and explained above. However, there are a couple of other media where a knife can be sharpened with a relatively decent result.

  • Mug Upside Down: This is correct. The bottom of a ceramic mug is coarse and can grind down the edge of a knife in need of a touch-up. However, it is hard to judge an even angle, and working with just a small ring of exposed coarse ceramic surface is not the best way to treat a nice knife.
  • Plate Upside Down: Similarly to the mug, a ceramic plate's bottom can be used in the same manner. However, this is not advised due to the uneven sharpening surface.
  • Glass Hone and Marble Sharpener: This method dates back to the beginning of the 20th century. A small inverted half-dome glass piece would hone a razor blade. Once honed, it would be rubbed against 2 circular pieces of marble for final sharpening. This video fully shows the extent of this unusual technique!

Holding a Sharp Knife

When using a sharp knife, secure your pinch comfortably around the bolster and the opposite side of the heel.

The above picture shows that my index finger is right above the bolster and my thumb wraps around the rest of it. The rest of my fingers are holding the handle securely. Your own pinch varies slightly in the positioning of your hand based on preference.

Final Thoughts

Knife sharpening is not something that you learn in one day; some chefs and sharpeners would say it can take years to master. It seems like every time I sharpen my knives I learn something new and improve on the practice. If you’re set on sharpening at home, using whetstones is a safe and very effective way to sharpen your knives. It is almost impossible to mess up a knife on a whetstone so don’t be afraid! Otherwise, I’d recommend going to a knife sharpener. You can always reach out to me or other Cutlery Experts with questions on sharpening and the tools needed to get the job done.

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