Knife Sharpening Basics – Sharpen Kitchen Knives

A sharp knife is important: easier to work with, and maybe surprisingly, safer to use. Not only do chefs need sharp knives for their job. Everyday cooking can become a lengthy and complex process with dull knives.

Before sharpening, it is essential to understand some basics regarding the angle, knife material, blade shape, and abrasives to use. And, of course, try to practice on a lower-quality, cheaper knife.

In the following article, we will cover the most important questions when it is about the sharpening of kitchen knives.

We will walk you through the steps of sharpening with whetstone, diamond stone, and oil stone, cover the differences between sharpening steel and honing steel.

Finally, we will explain the essential steps after sharpening and the maintenance of sharpening tools.

How Often Should You Sharpen Your Knives?

How often to sharpen knives? It depends on the condition of your knife – if it’s dull, get ready for sharpening. There is no other rule for it. The more usage, the more frequent sharpening a knife will require. There are some ways to test the dullness of the edges.

•  Glide the knife on your fingernail. If it slides without leaving a mark on it, your edge is probably dull.

•  Try to cut a paper, holding it between two fingers in the air. Cut downward but do not exert pressure; let the weight of the knife cut the paper. A dull edge, however, will grab the paper and won’t slice it.

• Go on and test it on a fresh ripe tomato. The soft edge and firm skin would give the knife a great test.

In the picture here, it shows an arrow sign on the tomato when using a dill knife.

 


Before Sharpening – Know the Angle

An essential question before sharpening is if you know the degree angle of the edge.

German (also called European, Wester, and American)-style knives generally have an edge angle of around 20 degrees, while Japanese blades are narrower, approximately 15 degrees, as the picture below shows.

It is vital to maintain the correct angle during sharpening. It may seem complicated, but there are many ways to find the right angle.

The most popular ones are the pinky method, angle sharpening guides, and sharpening guide clips.

The Pinky Method 

A simple way to find the right degree angle is by putting your pinky between the whetstone and the spine knife. This won’t be exact, but an excellent way to get a feeling about the close to correct angle.

The pinky method is not necessarily the best way for beginners but for those who often sharpen their knives enough to find the correct angle.

Angle Sharpening Guide

If you know exactly what angle your knife’s edges are, don’t want to damage them, or just want to make life a bit easier, get an angle guide! They come in a variety of sizes and forms, from 10 degrees to 20 degrees.

As the picture shows, use a rubber band to attach them to the end of the sharpening stone, place the knife blade on it, and maintain the correct degree. You can keep checking the angle and quickly correct it if necessary.

Sharpening Guide Clip 

Another guide for sharpening stays on the knife during sharpening and maintains a consistent degree angle during the whole process.

There is no need to overthink the angle or worry during the sharpening process if you get distracted for a second; with this guide, not a problem.

The only con with this type is that you cannot change the angle. If you have different types of knives, you will need more than one.


How to Use Sharpening Stones – The Main Steps

There are different ways to sharpen knives. Following in the section are the most common tools and steps that you can use to sharpen your knife.

Japanese Whetstone 

The following description will cover how to use Japanese whetstone for sharpening – however, the main steps are the same when using diamond and oil stones. We will point out the differences between these sharpening stones in each section.

A classic method of sharpening a knife is using a Japanese whetstones, also called a water stone or sharpening stone. For sharpening, a 1000 to 3000-grit whetstone is ideal – above that, the stone only refines and polishes the blade. Sharpening stones are very affordable (but of course, there are expensive pieces), and you can find them with two layers with different grits.

You will also need a stone holder to keep it steady during the process. You are moving the knife, not the sharpening stone! As the name shows, the sharpening stone must be used when wet because it protects the knife from the heat generated by friction. Have a clean cloth close as well to wipe the blade after the process.

First Step: Prepare for Sharpening

First, put the whetstone in the stone holder to support the tool. Make sure it is stable and not moving around.

It is essential to have maximum control over the blade during the sharpening process not to damage the edge.

Instead of a designated sharpening stone holder, you can choose a rubber liner or damp cloth/paper towel as well. Submerge the whetstone in water for several minutes and start using it only after it stops bubbling.

Second Step: Determine the Right Angle for Your Knife

Second, place the knife blade on the knife sharpening stone and find the right angle for the type of knife you have. You don’t necessarily need a tool for this, but it can be helpful for starters! In order to sharpen your knife correctly, adjust the angle accordingly.

Third Step: Knife Sharpening

To sharpen, the edge of the knife should face away from you. It can face toward you as well but be very careful and don’t cut yourself. With your dominant hand, hold the knife at the handle.

Place the heel on the sharpening stone and put your other hand in the middle of the blade, keeping your fingers flat, far from the edge, closer to the spine of the blade.

Gently push the knife edge down but not too hard – there is no need to exert too much pressure on the blade for sharpening.

Push the blade ahead on the sharpening stone, and as you reach the distant end of the whetstone, you should arrive at the tip of the knife as well. Alternatively, just sharpen a section of the blade edge at a time. Make sure you sharpen each section and avoid overlapping them.

However, this method is not the best because the entire edge might not get equally sharpened. You can choose to push and pull the knife or just push, lift, and push again. Sharpen one side, then the other of the blade, and don’t fidget about the right degree angle!


Oil Sharpening Stones

Oil stones look similar to whetstones, but you use oil lubricant for sharpening. They are primarily recommended for German manufacturer’s knives because of the type of material used for the blades. For oil lubrication, always use the type of oil recommended for the stone, often mineral oil.

As we said, the main steps are the same but here is a brief description of how to use them. First, make sure it is stable using a wet cloth or rubber mat. Apply a small amount of oil on the surface and rub it in the stone.

Find the right degree angle, align the knife to the stone, and slide it from heel to tip, applying even pressure throughout the blade edge. Hold the knife at its handle with your dominant hand, and place three or four fingers on the blade.

However, if you feel comfortable and want to ensure that the edges are equally sharp, change your hand when switching sides. Once you get the desired sharpness, flip to the medium then fine gradient to refine the edges.

Diamond Sharpening Stones

Another type of sharpening stone, the diamond-coated stone, is a great tool to get the sharpest knives. It is also very versatile – you can sharpen woodworking tools as well, not just kitchen knives. To make these sharpeners, industrial diamonds are applied on a usually metal surface, resulting in a solid abrasive surface.

Diamond stones quickly sharpen knives and can be used to flatten oil and whetstones (later about flattening). The main disadvantage is the initial cost; however, they will last for ten to twenty years once you invest.

Monocrystalline diamonds are the best but also the more expensive sharpeners. With usage, the diamond gets smaller, and the grit number changes. Monocrystalline stones maintain their shape and size for a very long time; hence, the grit won’t change.

To use a diamond sharpener, follow the same steps as with the whetstone. Make sure the stone is stable before usage. Next, wet the surface with water (not oil!) and keep it damp the whole time. Water is the lubricant that protects the knife from becoming hot due to friction. It also carries away the small metal fragments that are removed and won’t damage the fresh edges.

Put the knife on the stone at the correct angle. If needed, use an angle guide. Move the blade away from you – this is the safer way. Repeat the movement a couple of times and check the sharpness. Don’t exert a large pressure when sharpening because diamond stones are very tough and easily remove a lot of material if pushed too hard.


Sharpening Steel – If You Don’t Want to Use Stone

A very popular and easy method of sharpening kitchen knives is using sharpening steel. Important to remember, a sharpening steel and a honing steel is not the same! Below we talk about what a honing steel is and why it is necessary to use.

A knife sharpening steel is basically a rod coated with diamond or ceramics, which are harder materials than your stainless steel or carbon steel knife blade is made of. Keep in mind, if you want to sharpen a ceramics knife, choose a tool with diamond coating. There are different ways to use sharpening steel.

The safest method is to put the steel on a cutting board, the handle facing upwards, as the image shows. Next, find the right angle for the type of knife you have. Maintain the correct angle the whole time you sharpen.

Lay the knife against the steel and pull it down in an arching motion. Switch sides after every move to make sure the edges are equally sharp. The first couple of times, exert higher pressure, then lighten up at the end for a couple of strokes.

Alternatively, you can keep the knife in the air, as the picture shows. You can push the knife away from you or pull it towards you. Similarly, switch sides each time you push or pull the knife against the steel and maintain the correct degree angle. Don’t forget to remove the burr after the knife sharpening!

Handheld Sharpeners

Instead of a sharpening stone or steel, you can also choose using a handheld sharpener. These tools take away the pressure of finding the right angle, and it is safe to use, as it is unlikely to cut yourself while sharpening. These sharpeners have two stages: a coarse side and a fine side.

The fine side is safe to use even daily because it does not take steel off. It only realigns the blade, which makes it feel sharper and more comfortable to use. Don’t exert pressure; let the knife’s weight do the job. Push and pull the knife a couple of times until you get the desired result.

If you want to sharpen the knife, use the coarse stage first. It takes the fatigued metal off the blade to reset the edge. When using the coarse side, you have to apply light pressure on the knife all the way through.

You should hear an even grind all the way through the blade – it indicates that the metal is being removed and the fresh, sharp edge is being created.

Start at the heel, and after you reach the tip, start it again at the heel. Repeat the process no more than 3-6 times, and finish on the fine side.

Electric Sharpener – Buy or Pass?

It seems very easy to sharpen your knives quickly and effectively with an electric knife sharpener and reach that razor-sharp edge you always wanted. Additionally, they are very affordable, even cheap.

So, in theory, they are great. But should you use them? Especially on an expensive, high-quality knife, you spend so much money on? Rather not.

First, you cannot change the electric knife sharpener’s angle. Using a manual tool, you can get a very sharp cutting edge, but with the electric version, you rather reach a decent one. It will be good but not outstanding.

Second, and this is a much bigger problem: they can ruin your blade. After just a couple of use, an electric sharpener will remove so much of the metal that you can go and buy another one. The electric knife sharpeners are designed for cheap knives – but even if you choose a less expensive knife, there is no need to shorten its life with these electric tools.

Honestly, with sandpaper, you can reach sharp edges – there is no need to use an electric tool, even if you never sharpened a knife in your life.

It is easy to learn and, in the long run, much better for your kitchen knives and your wallet as well. In conclusion, avoid electric knife sharpeners and learn how to sharpen manually.


When to Switch Side and When to Stop Sharpening?

A common question is when to stop sharpening one side (when using a sharpening stone), and switch to the other, or when to stop sharpening. Usually, it only takes a couple of minutes to sharpen a knife.

There are methods you can use to test and check if the knife blade is sharp enough, but you can also try to find the burr.

Finding the Burr 

You can easily find for the burr, but it takes some time to feel it.

Place your thumb on the opposite side of the edge that you sharpened.

Slide your finger away from the edge, as the gif shows.

Don’t run your thumb along the side! The freshly sharpened knife, even the burr, can be sharp and easily cut your finger.

If you have difficulties finding it, a LED Magnifier can help.

The Burr After Sharpening

So, what is the burr exactly? The burr is a rough layer of metal on the blade. As you sharpen the knife, a layer of metal is removed from the edge.

Basically, it is pushed to and up the side, but it does not break down or removed all the way but shows up at the very tip of the edge. The fatigued, rough metal is removed from the sharpened edge, and the new material is exposed, which is fresh and sharp.

The presence of the metal layer, the burr, indicated that the sharpening process was successful. However, make sure the burr is as small as possible. If you grind away too much metal, that can weaken or damage the blade. You only want to remove a small amount of rough metal, just enough to get the fresh layer exposed and sharpened.

That’s why it can be hard to feel it when first sharpening. Be patient – it is a learning process. Once you feel it, no matter how subtle, you will be able to find the burr. Once you feel it, change side and sharpen the other edge.


Process After Sharpening Knife

The knife sharpening process doesn’t end with the sharpening itself. The two main steps are the following: removing the burr and polishing. Let’s see the details.

Removing the Burr

It is crucial to remove the burr after sharpening the knife, this is an extra layer of metal from the edges. The clean edges cut better and allow the sharpened edges to do the job. Essentially, you repeat the sharpening process but with only about half of the pressure. You only want to remove this extra layer, not more, so just slightly push the blade.

Move the knife from heel to tip and from tip to heel a couple of times, and test for its presence. Keep lowering the pressure until you can’t feel the burr anymore. You can also test for sharpness by the newspaper method or tomato method.

Polishing

After sharpening, you can choose further polishing the knife. The process refines the blade edge, create a very sharp knife, and gives it a nice shiny finish. It usually requires multiple steps, but with practice, you can find all the tools and necessary steps to get the desired result.

Just as with sharpening, practice polishing on a knife that you don’t feel bad about if something happens to it. Notice that polishing off the cutting edge and the blade is different, so you need to use sharpening stones with different grits.


Cutting Edge Polishing

For the process, choose a fine grit stone – you don’t want to remove a lot of extra material. Choose a stone with 4000 grit to polish the cutting edge until it reaches the desired sharpness. This will create a very sharp edge but keeps it durable.

Blade Polishing with Stone

To polish the blade, use a very fine stone – 6000-8000 ideally. You can even reach a mirror-like finish but can be used on the cutting edge.

This results in a razor-sharp knife edge that can be used to slice delicate ingredients. Keep in mind, however, that it will dull faster. You can also use a leather strop to create mirror polished blade.

Blade Polishing with Sandpaper

For this method, you will only need to get sandpaper. Using fine sandpaper between 320 and 400 grit is an excellent way to polish the blade. After sharpening, clean the blade with a wet cloth or paper towel.

You can use penetrating oil on the blade for lubrication. Before polishing, remove the excess oil – a small amount will be enough.

First, use 320-grit sandpaper all over the knife for several minutes on both sides. Switch to 400-grit sandpaper and rub the blade again to create the desired finish.


Honing a Knife – What it is? Why Important?

Close to the end, let’s talk about a step that many people don’t know much about. It is common to think that honing steels and sharpening steels are the same. Sure, they look very similar – but they are made of different materials and used for different purposes.

The sharpening steel sharpens your knife and has a coating of hard material. On the other hand, the honing steel is made of steel and does not sharpen the knife.

A knife’s constant usage will develop tiny teeth – they fold over and make the blade not so straight. It is not visible to the naked eye and cannot be prevented.

However, in order to keep your knife easy to use, it is important to realign the blade—that is where the honing steel comes into the picture.

You use honing steel in the same way as you use sharpening steel. You can also hone a knife daily if you use it very often. When using it, only exert light pressure – you don’t want to remove any metal from the blade.

Generally, it is enough to use it after every three uses of a given knife. Even though honing steel won’t make your knife sharper, the realigned edge is easier to use – so it will feel sharper.

A honing steel will serve you for years, even decades, in a regular household. There is no need to replace it regularly, but it depends on its price too. Generally, once you can’t feel the groves on the steel, it feels smooth; it is time to get a new one. It is easy to test with your fingernails – just run them along the steel to try it.


Maintain Your Sharpening Tools – Flattening Whetstones and Oil Stones

Finally, don’t forget: your sharpening tools need care too, not just the knives! Sharpening stones tend to wear down in the middle over time and create a hollow.

If you keep using these tools, the knives won’t be evenly sharpened, so it is essential to remove the high sides. This process is called flattening. Generally, you should flatten the whetstone sharpening stones before each use and after around 15 uses in the case of oil stones.

To flatten the stones, you can use sandpaper, a flattening plate, or a diamond stone. Using sandpaper is affordable: use 100-grit sandpaper on the oiled or wetted stone surface and rub it until flat.

Finally, use 400-grit sandpaper to finish the process. To keep the sandpaper stable, put it on a rubber mat. You should move the stone on the paper because the other way around would not result in a flat surface.

Some sharpening stones come with a flattening plate, but you can also buy one separately. Ideally, choose a silicon-carbide version. To flatten your sharpening stone, insert it in the stone holder, apply water or oil on the surface, and move the flattening plate on it until the surface is even.

A good method is making pencil marks across the sharpening stone – when the stone is evenly flat, all the marks will be removed.

Don’t forget, the flattening plate must be flattened sometimes with sandpaper. And if you owe a diamond stone as well, you can use that for flattening because the diamond is a very durable material.


Conclusion

Learning how to sharpen a knife is not that hard. It requires some practice and time to master this skill, but once you feel it, you are all set. It is best to practice on a knife that you don’t use very often and won’t miss if you damage it.

Keeping your knives sharp will make your kitchen life easier. Make sure before you start that you know what kind of sharpening tool the manufacturer recommends, and you know the blade’s angle.

But if you don’t feel like sharpening your expensive knives, a good sharpener professional will do the job for you.

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