The world’s sharpest knives probably belong to newlyweds. That’s because it’s all downhill from there—the more you cook, the duller your most important tool becomes. It's only through regular maintenance that chefs and home cooks keep their blades sharp.
So how often should you aim for? Well, the short answer is whenever they start to feel dull—which can vary depending on the quality of your knives and how often you use them. Can your knife cut a tomato cleanly? If not, it's time to sharpen it. You can also use the paper test: Hold a sheet of printer paper up and try to slice it vertically. If you have trouble hacking through the paper, your knife could stand to be sharper. For most home cooks, this will be two to three times a year.
For sharpening at home, you can use an electric sharpener or a whetstone, but stones are generally agreed to be the better choice, since they are gentler on your blades, relatively inexpensive, and easy to use. Here’s how to use them both:
If you have a very nice knife, sharpen it with a whetstone. A stone will set you back about $10 at the hardware store (although you can spend more on ceramic and glass models). Moreover, it’s a great meditative practice, like zen archery—except that you can do it in the confines of your own apartment.
Sharpening stones come in different sizes and grits (the stone's level of coarseness), which are often indicated by color, depending on the brand. Some stones have two sides: a coarser side for removing dents and sharpening very dull blades, and a more refined side used for polishing and edge refinement. The rule of thumb is to always start sharpening your knife on the coarse side, moving to the refined side to finish.
If your countertop is slippery, place a rubber mat or towel underneath the stone.
Some stones need to be oiled or soaked in water first; check the manual that comes with yours to be sure. If it’s two-sided, start with the coarser side.
Hold your knife at a 15 to 20 degree angle—this can vary slightly from knife to knife, so again, double-check the info that came with yours. (You can use a matchbook, a couple of pennies, or a ¼-inch binder clip to help keep everything at the proper angle.)
Holding the knife at the correct angle with one hand and the blade facing toward you, rest fingers of the other hand on the flat side of the blade and push it away from you, making 10 strokes. Flip it over and do 10 strokes on the other side.
Test and, if it’s still not sharp enough, repeat until your knife is back to its former glory. That’s it!
The electric knife sharpener is the fastest way to restore your blade to health, but it’s also the most brutal. The edge of a knife is a carefully tapered compression of metal layers, and everyday thwacking sends the atomically aligned edge into disarray, or worse—it can chip tiny divots into the metal. An electric sharpener simply obliterates the old edge and tapers a new one. For the average knife, there are worse fates. But, if you happen to own a Japanese cold-forged sabatier, this is a sad, sad day indeed.
Once your knife is sharpened, you'll want to keep it that way. It’s a good habit to use a honing steel every time you take out your knife. A steel is the fat round thing in your knife block that looks like a metal lightsaber. This method is like two minutes of cardio for your blade; it quickly aligns all of the metallic ions in the knife's edge so that you can part your proteins with ease and precision. Simply hold the knife in your dominant hand, lay it nearly flat against the steel at about 22 degrees (think about it as half of 45 degrees), then draw it across the steel 10 times on each side. The steel won’t restore an edge to a dull knife, but it will help you keep an edge longer on a well-maintained knife.
This article was updated in November 2020 to add all the best sharpening options.