Knowing how to sharpen your kitchen knives is a skill that every home cook needs. It means better cooking and safer prep. Even if your knives weren’t a particularly big investment, you’ll still need to put some time into keeping them in good shape. Let us sharpen your skills. Get it?
A long time ago in a kitchen far, far away, I got my first set of cheap kitchen knives. Because they were made of inexpensive steel, they became blunt and dull very quickly, and as this happened, they required more pressure to cut. As a result, they were far more likely to slip. Once, while I was trying to slice a tomato, the dull edge was crushing the flesh and not slicing into it cleanly. As I pushed harder, the knife slipped. In an instant, I was bleeding.
It took me a few years of bumbling around to realize it, but I finally figured out sharp knives are safe knives. In addition, they create clean cuts and more consistent slices and dices. The sharper the knife, the easier it is to mince fresh herbs without bruising them and to fillet a fish without cursing. A sharp knife can even help minimize the release of the fumes that make you cry when you slice an onion.
I eventually replaced my cheap knives and invested in high-quality knives. While they remain sharper longer, they still require sharpening. In fact, knowing how to keep kitchen knives properly sharpened is just as important as knowing how to use your knives. And specialty sharpening tools are an essential part of the process.
How to tell if your knife needs sharpening
Exactly how do you know when it’s time to sharpen your knife? First, inspect the knife. Look at its edge. If you see small nicks or a flattened area, it needs sharpening.
You can also perform any of several sharpness tests. One of the most common tests requires just a sheet of paper. Hold the paper securely with one hand and turn it in landscape position with the bottom edge of the paper resting on the countertop. Then draw the blade of your knife gently down through the center of the paper, starting with the heel of the blade (the wide part closest to the handle) and gradually moving the part of the blade slicing the paper toward the tip. A sharp knife will easily slice through the paper with little pushing. A dull knife will, well, you can figure that out.
If you’re not a professional cook who creates hundreds of meals each day, then you don’t need to do daily or even weekly knife sharpening. I run all my knives through my sharpening process every 5 to 6 weeks.
Which knife sharpening tool is right for you?
There are two primary methods for sharpening a knife. One is using some sort of an electric or manual sharpening system. The other, a whetstone, is quite old-fashioned and simple. While I’ve used a whetstone the most over the years, it’s not as easy nor as convenient as either of the other methods. Both methods are complemented by honing the knives using the honing steel that comes with a set of knives. (More on that later.) I keep both a sharpener and a honing steel in my kitchen at all times.
Electric knife sharpeners
My tool of choice is an electric knife sharpener. It comes with an assortment of belts with varying degrees of coarseness (called grit) to sharpen the blade, and you can adjust the angle so your knife gets a consistent and proper angle when sharpening. You can also adjust the speed of the belts from slow to fast.
My preferred sharpener is the Ken Onion Work Sharp tool. There are other brands available for the home cook, some as expensive as the Work Sharp ($149.95 MSRP) and others at about half the cost. It’s paid for itself through the years.
When the time comes for me to resharpen the knives, I use the P1000 medium belt to repair the edge quickly. I slowly pull the blade from heel to tip about 3 times on the right side and then I check the edge for a burr along the entire edge of the blade by gently brushing my fingertips across and away from the edge of the blade. I continue the process until the entire edge has a burr. A burr is a deformation at the edge of the blade. One will feel it as a small ridge when you slide your thumb down the blade, starting at the tip of the knife blade and moving to the bottom edge, not the other way, to avoid cutting yourself.) Continue until there is a burr along the entire blade. Getting the burr provides for a more consistent new edge.
I repeat the same number of strokes on the left side of the blade. Then I change to the P3000 fine belt and alternatively sharpen each edge.
An added benefit of spending a few more bucks on an electric sharpener is that if you severely damage the knife, you may be able to fix it at home. I recently used my Global cleaver to hack away at a bone and this severely damaged its edge. To quickly fix the blade, I started using a P120 grit to remove the nick and reshape the entire edge, then moved on to the P65 grit before moving on to my normal sharpening process. If I had to get the knife repaired by a knife sharpening service, I would probably have spent half as much as my Work Sharp tool cost me. But in 10 minutes with my electric sharpener, I was able to rebuild the edge myself.
The classic whetstone was my primary method of sharpening knives when I started cooking. However, it takes a lot of practice to be able to hold the knife edge at the correct angle for sharpening. There are tools that you can purchase to clamp onto the knife blade to keep the edge at the correct angle while using the stones.
Using a whetstone requires a bit of prep before using. If it’s not a new stone, you need to check that it has a flat surface since pulling and pushing the blade through the middle of the stone can create a “belly” in the stone. You can use a “Nagura” stone or a “flattening plate” to clean and reset the whetstone.
The basic process to prepare your whetstone is the same, whether it’s a water or an oil stone. In my opinion, water whetstones are cleaner and easier to work with. Before using your whetstone, submerge it in a container of whichever liquid it requires for at least 15 minutes. Also, keep a small squeeze bottle of water or oil available so you can keep the stone wet when sharpening.
It’s a good, safe practice to place the stone on a folded damp cloth or towel placed on a flat surface, whether on your countertop (or your workbench) as you would do beneath a cutting board, to keep the stone in place while sharpening your knives.
Whetstones have two sides, one coarse and the other fine. Start with the rougher, coarser side of your stone facing you. Prep the sharpening stone by dispersing a bit of water or oil across its surface. Now you are ready to start sharpening!
Start at the short end of the stone furthest from you and, holding the blade at about a 20° angle to the stone, slowly pull the knife across the stone towards you in one smooth motion, exerting about 4 to 6 pounds of downward pressure the entire length of your stroke. You’ll want to start pressing at the handle end of the blade and finish at the point.
Repeat this action 5 or 6 times, and then check to see that there is a burr alongside the length of the blade. A burr is a deformation at the edge of the blade. One will feel it as a small ridge when you slide your thumb down the blade, starting at the tip of the knife blade and moving to the bottom edge, not the other way, to avoid cutting yourself.) Continue until there is a burr along the entire blade. Getting the burr provides for a more consistent new edge.
Repeat this motion a few more times until you achieve the burr. The dullness of your blade will determine the number of times you need to repeat this process. Keep track of the number of strokes, as once you have that burr, you’ll want to repeat the process on the other side using the same angle, amount of pressure, and number of downward motion and strokes. Return the knife to the original side and then draw the knife from the point to the bolster, repeating this motion 5 to 6 times, then do the other side of the blade 5 to 6 times. Then turn over your stone to the fine side and give each side 3 to 4 strokes, turn the blade over and do 3 to 4 strokes, but don’t worry about a burr, as this process is to further sharpen the edge of the blade.
Tip: to get a feel for that amount of pressure, take a chef knife in your hand, place it on its side atop a scale, and press down until you see 4 to 6 pounds show on the scale.
Another option is a type of sharpening tool that’s made of diamond materials and doesn’t need any lubrication such as water or oil. It comes with a guide that is attached to your blade, so you have the right angle, then you pull the sharpeners along the blade. I prefer this to the whetstone, and my preferred model is the Diafold Magna Guide system.
Keep in mind that a honing steel does not sharpen the knife, it only helps the tiny, microscopic metal particles of the steel edge realign.
Should your test reveal that the knife is dull, you can use a honing steel to quickly correct the edge via a realignment. Basically, when you hone the edge of your knife blade, you are pushing the uneven edges back to the center of the knife, basically fixing the burr that has formed during use. Honing is a quick fix, so you can use the knife immediately and properly sharpen it later. It is made either of metal or ceramic. Despite what you may have seen on old TV shows, you don’t need to hone your knife before each use. After every few uses will be more than adequate, even for the ones you use the most.
When it comes to using a honing steel, I prefer to anchor my steel on a cutting board rather than hold it in one hand as I find it to be a safer method for home cooks. Take your knife and hold the back edge at a 12° to 15° angle to the steel, then touch the heel of your knife to the top of the steel and apply a little bit of pressure, preferably 4 to 6 pounds.
Slide the knife down the steel using a left to right motion. The idea is to touch the entire edge of the blade in every pass. Repeat on the other side, about four or five passes on each side.
What angle do I use to sharpen my knives?
Asian knives require an approximately 16° angle.
Western and European knives, such as Wusthof, Swilling, and my artisan knives, require an angle closer to a 20°.
In my opinion, the hardest thing about using a whetstone is determining the correct angle for holding the knife to assure the sharpest edge and then being able to hold the knife at that angle throughout the process.
Let’s assume you have a Western-style knife and you want to sharpen it at a 20° angle. The simplest way to get the right angle is to use a guide.
However, if one is not available, you can try to approximate the correct angle by following the “rule of halves” methods. First, hold the knife with the blade down at a 90° angle. Then slowly move the knife blade to reach a 45° angle so you’ve made the first “half” distance between the 90° and the top of your whetstone. Now halve this distance one more time and you will be at approximately 22° or 23°, which is close to the 20° recommended angle. You can make subtle adjustments as needed. Now that the correct angle has been achieved, you can commence the sharpening process.
How do I know when my knife is sharpened?
You can now perform the paper test again, and you should see a significant improvement in the edge of the knife gliding through the paper.
How to care for your knives so they stay sharper longer
I hand wash my knives and place them in a knife block, sharp side up, to protect the edge. Never place knives in a dishwasher, as they can thrash about under the water pressure and come in contact with other utensils, which will damage the blade.