How to sharpen a knife

How to sharpen a knife with a Stone

Good water stones are the best way to keep your excellent knives sharp for the longest time, but only if you know how to actually use them. This guide gets into the nitty-gritty of the angles, strokes, and science behind proper sharpening.

Whetstone Sharpening Stones

This advice on buying and maintaining water stones (a.k.a. whet stones or sharpening stones) and, more importantly, actually using them  It answers questions about soaking, angles, checking your “burr,” and finishing the job the right way.

There are, to be sure, shops that sharpen knives, and electric/automatic sharpeners just an Amazon order away. But using water stones has value beyond sharpness:

Not only will it give you the best edge, it also removes the least amount of material. With a fine enough grit, your knife should be able to take hairs off your arm when you’ve finished. Additionally-and I’m not kidding about the importance of this one-the act of sharpening your knife will help you create a much stronger bond with your blade, and a knife that is treated respectfully will behave much better for its owner.

When buying a water stone, look for a large one, at least 2.5 inches wide by 8 inches long, and an inch in thickness. Stones come in various grit sizes, ranging from around 100 and up to 10,000+. The lower the number, the coarser the grit, and the more material it will take off of your knife.

How to Use a Whetstone

When buying a water stone, look for a large one, at least 2.5 inches wide by 8 inches long, and an inch in thickness. Stones come in various grit sizes, ranging from around 100 and up to 10,000+. The lower the number, the coarser the grit, and the more material it will take off of your knife.

Bear in mind: The higher the grit, the sharper the edge you will get, but the more strokes it will take to get you there.

I recommend keeping two stones in your kit. One with a medium grit (around 800 or so) to perform major sharpening jobs, and one with a fine grit (at least 2,000) to tune the edge to a razor-sharp finish. For real pros, a stone with an ultra-fine grit(8,000 and above) will leave a mirror-like finish on your blade, but most cooks won’t notice the difference in terms of cutting ability.

If you only have the budget or space for a single stone, I’d recommend one with a grit between 1,000 and 1,200.   Two sided stones are also available (coarse and fine grit), but are usually of inferior quality.

You will also need astone fixer to repair any inconsistencies in the surface of your sharpening stones.

Carefully dry your stones after each use, and store them wrapped in a kitchen towel in a dry, grease-free environment. Oil can soak into the porous material, ruining its sharpening ability (and your chances of ever slicing your onions thin enough for that soup).

And finally, remember to hone your knife on a steel every time you use it. While this process won’t actually take any material off the blade, it will help keep the blade aligned, making slicing and dicing much easier.  How to sharpen knives with a wet stone


knife sharpening
prepare station for knife sharpening

When working with water stones, it’s essential to submerge them in water for at least 45 minutes before using. If the porous stones are not fully saturated, they will dry out during sharpening, causing the knife blade to catch, and giving your edge nicks and dings. Soak both your stones, and your stone fixer.


knife sharpening
prepare station for knife sharpening

Place your stone on a towel set over a cutting board. Keep a container of water nearby to keep your stone constantly moistened during the sharpening process. The stone should be oriented with the short end parallel to the edge of the counter.


First knife sharpening strokes

How to sharpen a knife correctly by placing the heel of your knife on the far edge of the stone, holding the blade gently but firmly with both hands at a 15 to 20 degree angle. Using even pressure, slowly drag the knife over the stone towards you down the length of the stone while simultaneously moving the knife such that the contact point moves towards the tip of the blade.


knives sharpen

Be careful to maintain the 15 to 20 degree angle as you pull the knife across the stone. Pressure should be firm, but gentle. The blade should glide smoothly across the stone as you pull.


How to sharpen knives

Each stroke should finish with the tip of the knife touching the bottom of the stone. Lift the knife, reset the heel at the top of the stone, and repeat.


sharpening knives

As you repeat the process, a thin film of silty looking water should collect on top of the stone and on the blade. This abrasive liquid will gradually take material off the edge of your knife, sharpening it.


check edg for burr

As you continue to repeat strokes on the first time, eventually a tiny burr will form on the other side of the blade. To check for it, place the blade on your thumb, and pull it backwards. If the burr has formed, it should catch slightly on your thumb (with really fine grit stones, say 2000 or above, you won’t feel this). This may take up to 30 or 40 strokes, and is the indication that you should switch and start sharpening the other side.


wet stones for knife sharpening
wet stones for knife sharpening

To sharpen second side, place the heel of the blade near the base of the stone, again maintaining a 15 to 20 degree angle. Gently push the blade away from you while simultaneously dragging across the stone towards the tip.


whetstone knife sharpeing

Your stroke should end with the tip of the blade against the top edge of the stone, still maintaining a 15 to 20 degree angle. Remember to moisten your stone between strokes if it begins to dry out. Repeat for as many strokes as it took you to form the burr on the first side.


stone fixer fixes worn stones
use stone fixer to smooth whetstones surface

After repeated use, your stone will begin to develop grooves in it, which can hinder its sharpening power. To fix it, use a low-grit stone fixer. Place the fixer flat against the stone, and push it back and forth to grind down the stone and create a new, flat surface.


knife sharpener

You should have a dedicated towel for this purpose, as the grit from the stone will never come out. After carefully drying the stone (allow it to dry on a rack for at least a day), I store my stones wrapped directly in their towels.


how to sharpen a knife with a whetstone


After sharpening, hone your blade on a honing steel in order to get the edge in alignment, then test it for sharpness. Some people recommend trying to slice a piece of paper in half by holding it up and slicing through it. I find that even a relatively dull knife will pass that test, yet fail at other kitchen tasks.

The best test is to simply use the knife to prep a vegetable. Do you notice any resistance? Does it fly through that onion? Can you slice a ripe tomato thin enough to read through it? Yes? Then you’re done! Now, you know how to sharpen knives with a whetstone.