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Stop Using Dull Knives: A Beginner’s Guide to Whetstone Sharpening

When you're using any type of cutting tool, like a kitchen knife or pocket knife, you should always check the sharpness of the blade first. Dull blades can slip off the target surface, putting your hands and fingers at risk of being cut. Learning how to sharpen a knife with a whetstone is one of the best ways to keep your blades sharp.

Using a simple whetstone grit guide, you can learn how to sharpen a dull knife blade, gradually working your way up from coarse grit, to medium, to fine, and finally to stropping after whetstone sharpening. This process will ensure your blades are as sharp and accurate as possible, but only if done right. Use this guide to find out more about why whetstones are so highly recommended and learn whetstone sharpening for beginners.

What Is a Whetstone and How Does It Work?

A whetstone is a type of sharpening stone. In fact, ‘whet’ is an old word that actually means ‘to sharpen.’ “Whetstones are my personal favorite way to sharpen a knife. You get the best, cleanest edge. If you’re serious about your knives, this is the way,” says Jordan Schmidt, co-founder and CCO of Schmidt Bros. Cutlery.

Whetstones are essentially a block of abrasive material that is used to sharpen blades. This is achieved by grinding away tiny bits of metal to create a fine, sharp edge. Whetstones come in various grits, allowing you to shape the edge, then polish it to a fine finish. These handy sharpening tools also use either water or oil for lubrication and to keep the stone from clogging, ensuring smooth sharpening action.

Choosing the Right Whetstone

Grit Levels Explained

Before you begin sharpening a knife, you need to check the blade and determine what grit is most suitable for the current state of the knife. Whetstones come in different grits, which essentially refers to how coarse the stone is. Coarser stones will remove more material from the blade, while fine grit stones are intended for polishing the edge to razor sharpness.

Generally, you should start with coarse grit whetstones for dull blades, medium grit for general sharpening, and fine grit for finishing. The grits are typically numbered so you have an easy time figuring out which one you need for the job. Coarse grit is typically between 120 to 400, medium grit falls between 800 to 2,000, while fine grit is considered anything that is 2,000 or higher.

One-Stone vs Two-Stone Setups

When you are sharpening your blade, you will need to decide whether it is better to have a single stone or two stones for the process. A single whetstone can be used for effective general sharpening, which is where medium-grit stones work best, but if you really want a honed and polished edge, then it’s a good idea to have a coarse- or medium-grit stone for shaping the blade and a fine-grit stone for refining the edge of the blade.

Alternatively, you could invest in a dual-sided combination whetstone, which has a different grit on each side, giving you the same benefits of a two-stone setup without needing to pay for two separate stones. Just keep in mind that a dual-sided whetstone will wear down and need to be replaced faster than if you had two individual stones.

Water Stones vs Oil Stones

You can choose between using a water stone or an oil stone for sharpening your blades. The main difference is in the name: Water stones use water for lubrication while oil stones use oil. However, there are other factors that you should consider when making this decision.

Water stones tend to cut faster and cleaner, and offer a wider grit range for a very fine edge, but they also wear down faster and require frequent flattening to ensure the whetstone maintains the correct knife sharpening angle. Oil stones are slower and tend to be messier than water stones, but they are also more durable and better for rust prevention, especially on carbon steel tools, making them a lower maintenance option that is best for tool blades, rather than modern hard steel knives.

Preparing Your Whetstone Properly

Do You Need to Soak Your Stone?

Soaking a whetstone is not always required, so it’s important to pay attention to the type of stone you have before soaking it in water. Try a splash-and-go test by putting a few drops of water on the stone. If the water is absorbed and the stone darkens, then it needs soaking, but if the water beads on the surface, then it is a ‘splash-and-go’ stone that won’t require soaking.

Similarly, if you have a fine grit whetstone, then you can typically just splash the stone with water instead of soaking it, while an oil stone will need to be lubricated with oil rather than being soaked or splashed with water.

How Long to Soak (And When Not To)

You don’t want to leave your stones soaking indefinitely. Generally, most coarse- and medium-grit whetstones will only need to be soaked for about 10 to 20 minutes or until air bubbles stop emerging, which is a clear indicator that the porous stone has been fully saturated.

If you have a fine grit whetstone or a splash-and-go stone, then you only need to quickly splash the stone with water due to the denser binders these stones are made with. In fact, over-soaking these stones causes them to become too soft, leading to cracks and crumbling.

Setting Up a Safe, Stable Work Surface

It is essential to have a safe and stable work surface when sharpening a blade with a whetstone. This is to help ensure that the stone won’t slip while you are working. Ideally, you should have a heavy, stable table, workbench, or counter that won’t wobble or shift, with a flat and durable surface that is strong enough to handle the downward pressure.

The work surface should sit at about waist or elbow height, depending on your personal preference, allowing you to use your body weight effectively while maintaining a comfortable posture. Use a whetstone holder to secure the whetstone, or even a bench vise for heavy-duty setups, so that you can ensure that the stone won’t shift or slip, but just make sure not to over-tighten the vise or you may risk cracking the stone.

Your whetstone will start to get an uneven surface from sharpening, so you'll need to flatten it regularly (by rubbing it against a coarse flattening stone).

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Knife Sharpening Basics

Finding the correct angle to sharpen the blade is necessary to get the desired result. Most Western-style blades should be sharpened at 15 to 20 degrees. Find the right angle and hold at this angle for a consistent result.

“Soak the stone if it’s a water stone, keep a steady 15 to 20 degree angle, and make smooth, even strokes from heel to tip. Flip sides often so you raise and remove the burr evenly. Take your time; that’s where people usually mess up,” explains Chef Jason Heiselman, certified nutritionist at Hungryroot.

Creating a burr formation when knife sharpening is a clear sign that the two bevels of the blade have met, forming a new, thin edge. At this point, you should flip to the opposite side and raise a burr there too, then use a finer grit stone to polish the edge and remove the burr.

How to Use a Whetstone

Choosing the Right Grit (Coarse vs Medium vs Fine)

Inspect the blade to determine whether you should start with a coarse-, medium-, or fine-grit whetstone. Generally, you only need a coarse-grit whetstone if you have neglected the blade or there is significant damage you need to repair. In most cases, you will start with a medium-grit whetstone to shape the edge, while a fine-grit whetstone will be used afterwards to give the blade a finishing touch.

Sharpen the First Side

The most difficult part of the process is to learn the right type of strokes, what type of pressure to apply, and how to maintain a consistent angle. “Use smooth strokes, from heel to tip, pushing as if slicing a thin sheet off the stone,” says Schmidt. The key to effective sharpening is consistent pressure, so avoid using wrist movements. Instead, move your whole arm to keep the blade’s angle stable against the whetstone.

Check for Burr Formation

When you feel like you have sharpened one side enough, check for burr formation. Schmidt says to “feel for the burr. That little lip of metal means the edge is forming correctly.” The burr indicates that the two bevels of the blade have met, forming a new, extremely thin edge or apex. Gently run your fingernail or thumb away from the edge on the side opposite where you were sharpening. If you feel a slight catch or hook, the burr is there.

Switch Sides

Once you have confirmed there is a burr on one side, you can flip to the other side of the knife and repeat the sharpening process until a burr forms on the second side. Make sure to maintain a consistent angle and even pressure when sharpening the second side so that the edge you create is sharp, accurate, and evenly formed.

Move to Finer Grits

If you leave the burr, the edge of the blade will be weak and will tend to roll over immediately, making the knife feel dull. To correct this, you should switch to a finer grit whetstone, then use lighter pressure and fewer strokes on each side of the blade to reduce the burr as much as possible.

Finish With Light Strokes or Stropping

The final passes on each side of the blade will refine the edge further. This means that you don’t want to use a lot of pressure, or you may end up removing more material than necessary, which is why stropping is highly recommended. “Finish with a strop (a piece of leather used in blade sharpening and polishing) to remove any micro-burrs and give your blade that razor feel. If you do this slowly and thoughtfully, you will get an edge that performs better than most knives ever do right out of the package,” Schmidt says.

Common Whetstone Mistakes (and How to Avoid Them)

Using the Wrong Angle

When you use a wrong or an inconsistent angle while sharpening your kitchen knife, you can create an uneven, rounded, or wavy edge that makes the knife difficult to use properly. “I’ve taught a lot of people how to sharpen over the years, and this is a mistake I see over and over. If your angle changes, your results will too,” notes Schmidt. Try to lock your wrists and hands, using your whole arm for the movement to help keep the angle consistent.

Too Much Pressure

It’s necessary to also pay attention to the amount of pressure you are using while sharpening the blade. Let the whetstone work properly by gently gripping your knife and only using light pressure as you sharpen the blade. If you do apply too much pressure, you may chip or otherwise damage the blade. You also risk wearing down the sharpening stone unevenly, which could cause issues with accuracy in the future.

Skipping Burr Formation

A clear sign that you are sharpening a blade correctly is when you can feel that a burr (a tiny metal lip) is forming on the blade. This indicates that you have sharpened all the way to the apex of the edge and need to switch sides. So, if you sharpen too lightly or not long enough, you may not actually form this burr, resulting in a dull, fragile edge that cannot cut as intended.

Not Flattening the Stone

When you are sharpening a blade there is a high chance that you will only use a portion of the whetstone, which can lead to forming a concave or dished surface in the stone that can make it difficult to maintain a consistent sharpening angle. Flattening the stone (more on that below) removes the excess material that sticks up higher than this concave area, creating a flat surface to ensure better results and consistency. It also prevents the dishing from worsening over time.

How to Test Sharpness Correctly

Paper Test and Food Test

There are a few simple ways to tell if your knife blade is sharp enough, including a paper test, food test, and the performance of the blade during use. “If your knife starts slipping on a tomato or tearing herbs instead of slicing them, that’s your sign,” says Schmidt.

To perform a paper test, use the knife to slice copy paper or newspaper that is held taut at a 45-degree angle. A sharp blade should be able to cut smoothly through the paper without snagging, indicating good sharpness. To perform a food test, use ripe tomatoes or grapes. If you can slice through a tomato or grape without a sawing motion or applying more than a light amount of pressure, then the knife is still sharp enough for honing, instead of sharpening.

Visual Edge Inspection

You can visually inspect the sharpness of a knife by holding the blade under a bright light and looking for any light reflecting off the cutting edge. If the knife is sharp, then you will see a smooth, dark line, but if it is dull or damaged, you will see shiny spots or a continuous bright line that indicates dullness, nicks, or chips that require your attention before using the knife.

Why Shaving Hair Isn’t Necessary

Shaving hair with the blade of a knife is an older and less reliable sharpness-testing method that was once widely used. However, hair has a lower resistance than many of the items that you will be using the knife to cut, so even if the blade can cut through hair it may actually still be too dull for common tasks like slicing tomatoes.

Whetstone Care and Maintenance

Flattening Your Stone

If you don’t regularly flatten your whetstone, then it will gradually develop a groove which will impact the shape of the blades you are sharpening. This is especially true for softer water stones, so you need to use a diamond plate or lapping stone to flatten the whetstone. It’s recommended to draw a grid with a pencil on the whetstone and rub it with your flattening tool until the lines disappear. You can also check the flatness with a straightedge ruler to verify that the stone is flat.

Cleaning and Drying After Use

After you have finished using a whetstone, rinse it thoroughly with water to remove any metal filings and slurry that was created while sharpening blades. If necessary, gently scrub the whetstone with a brush to get rid of any stuck-on debris. Once it is clean, place it in a well-ventilated area away from direct heat, sunlight, or freezing temperatures, so that it can air-dry completely.

Storage Best Practices

Safely storing your whetstones is important for their ongoing durability and longevity. If you're someone who frequently uses your whetstones, like a professional chef, then you may want to store some stones submerged in water in a lidded container. Just make sure to change the water regularly and add a drop of bleach to prevent bacteria formation. Also, if you won’t be using the whetstones for a day or more, remove them instead of leaving the stones soaking indefinitely.

Infrequent users, like home cooks, should store their whetstones in a dry, stable location with good air circulation, rather than leaving them in a sealed bag or a damp location. Keep the stones indoors and away from extreme heat or freezing temperatures to prevent cracks from temperature shifts. Additionally, avoid stacking heavy stones on top of each other, as this pressure could crack the lower ones.

Whetstone FAQs

How Often Should You Sharpen With a Stone?

The frequency with which you sharpen your blades with a whetstone depends on how often you use your knives and what you cut with the knives. “Sharpening removes metal to rebuild the edge. Honing straightens the little burrs that bend with everyday use. I hone constantly, but I only sharpen when a knife truly needs it,” notes Heiselman. On average, you should hone your knives after every use or every few uses, while you should sharpen your knives about once every one to three months.

Can Whetstones Ruin Knives?

When used incorrectly, any sharpening method, including whetstones, can ruin a knife blade. However, Heiselman says that “most chefs use whetstones, and they’re great, especially for high-end steel. I also use a belt sander or sandpaper since I make knives. It’s incredibly fast and gives me a razor-sharp edge with a lot of control.”

Do Japanese and Western Knives Use Different Angles?

Japanese and Western knives do use different angles for the blades. Generally, you can expect Japanese blades to have sharper, acute angles ranging from 10 to 15 degrees, while Western blades use broader angles ranging from 15 to 22 degrees.

Is Stropping Required?

Stropping is not strictly necessary for a functional knife blade, but it is a recommended final step that will allow the blade to achieve maximum sharpness, while removing any remaining burrs and refining the edge geometry.