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How to Sharpen a Knife with a Water Stone (Video)

At some point in every knife you will ever own’s life, it’s going to need a sharpening. Even if you bought one of those As-Seen-On-TV-Cuts-A-Soup-Can knives (which, don’t do that, just buy a real knife), it’s still going to need to be fixed up at some point. A dull knife not only slows you down in the kitchen, it’s more dangerous. The overcompensation in pressure and speed that you’ll apply with a dull knife could result in damaging the food or yourself (think avocado hand, but worse). What we’re trying to say is sharp knives are good knives.

Sharpening a knife takes skill, though, so we went to a pro for help: Eytan Zias, owner of Portland Knife House.

The first tip, Zias says, is to avoid gadgets: “Everything you use to sharpen a knife or to hone a knife has to be freehand.”

Those grinders and pull-through machines that are made by the same company that sold you that can-cutting knife? Sorry, but they don’t work like a water stone does.

Portland Knife House
Tomas Patlan/The Manual

What You Need

All you need to successfully sharpen a knife, Zias claims, is a water stone (a traditional Japanese whetsone) and a way to flatten it. After that, you’ll be completely self-sufficient.

Once you’ve got that mindset, you’ll need to make sure you’ve got the right equipment. For most sharpenings, he says, you’ll want a medium grit stone (800-1,200 grit). If your knife has no edge whatsoever, you’ll want a coarser grit — around 400 grit being ideal.

Before we get to the actual sharpening, a quick note about honing and honing rods. The best honing rods, Zias says, are made of ceramic. If you are sharpening your knives yourself, you don’t necessarily need one, but if you plan to take your knives to a sharpener, then honing a blade when you first realize it feels dull will extend the time between sharpenings.

Portland Knife House
Tomas Patlan/The Manual

How to Sharpen a Knife with Your Water Stone

In the video above, Zias demonstrates the technique with a chef’s knife, but the same method could be used on a pocket knife or non-kitchen utensil.

  1. Place your stone on a flat surface and sprinkle with water.
  2. Take your flattener, sprinkle with water, and use to flatten the water stone. Without a flattener, your water stone will quickly warp and become useless, Zias says.
  3. Find your angle. Every knife will have a different angle, and knives will have different angles over the course of their lives as well, so the best way to find the edge is visually. Look for where the contact is being made between the knife and the stone. If there is no visual cue such as a patina, Zias recommends using a sharpie to mark where you will sharpen to.
  4. Test you angle. Set the angle little higher and do a few test swipes. Stop and look where the scratch pattern is on the knife. To thin out the blade, you’ll take a lower angle, which will result in a wider bevel. For a more durable edge, you’ll raise the knife up to a higher angle.
  5. Once you find the angle, you’ll want to adopt the Japanese method and remove all the variables. “Every time you pick the knife up and put it down, you’re introducing a slightly different angle,” Zias says.
  6. Run the blade black and forth on the chosen angle, making sure the blade never leaves the stone and the fingers never leave the blade.

Your dominant hand will do just about everything, Zias says. Hold the knife in a pinch grip as you would when using it and lock your wrist, using only your shoulder and elbow to move the arm. Your second arm, he adds, will rest above the edge of the knife and works to focus the energy and pressure on the blade.

As far as how many strokes your knife needs, that answer is up in the air. It depends on a variety of variables: coarseness of the stone, dullness of the knife, et cetera.

Portland Knife House
Tomas Patlan/The Manual

“The real answer is until you raise a burr,” Zias says. A burr is a small lip of metal that you’ll be able to feel along the edge of the blade. Once you find the burr, you’ll flip the knife over and do the same thing. The burr will form quicker on the second side.

Next, you’ll move onto the stropping method to remove the burr. Using the same angle as sharpening, you’ll alternate strokes with light pressure. You want to work until the burr falls off or gets cut off, Zias says. At this point, if you started on a coarse grit stone, you’ll move to a medium grit and repeat the process.

Finally, run the blade over a leather bench strop. You’ll be able to feel if there are any burrs left; it also polishes any teeth left on the knife.

With the hard work done, Zias says, there’s only one thing left to do — test it!

Testing Your Knife

If you can test it on the item you’re going to be using the knife for (tomatoes, et cetera), use the item. If not, you can test it on paper. On the cut paper, you’ll want to look for a clean cut and little fiber sticking up on the cut edge.

If you want to up look like you’re living dangerously, you can try the shave test and see if the knife smoothly takes some hair off your arm.

Portland Knife House
Tomas Patlan/The Manual

Practice, Practice, Practice

Zias says if he could boil proper knife sharpening technique down to one word, it would be “practice.”

“We can teach you everything you want to know about sharpening, but you’re not going to be able to sharpen unless you put in some time.”

When you set out to learn how to sharpen, Zias recommends sharpening all of your knives. Then your mother’s knives. Then your neighbor’s knives.

Article originally published by TJ Carter on April 10, 2015. Last updated May 6, 2019 by Sam Slaughter.

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