Knife Skills: How to Sharpen a Knife
There is nothing more frustrating in the kitchen than a dull knife. Not only does it make prep work a chore and your finished product less attractive, it's also downright dangerous. A dull blade requires more pressure to cut into a food, and can easily slip off of a tough onion skin and into your finger. Ouch.
Most home cooks should sharpen their knives at least twice a year, and much more frequently if they use their knives every day. There are three ways to go about it.
Method 1: Use an Electric Sharpener. A good quality electric sharpener is an option, but I strongly discourage their use. First off, they remove a tremendous amount of material from your edge. Sharpen your knife a dozen times, and you've lost a good half-centimeter of width, throwing it off balance, and rendering any blade with a bolster (i.e. most high quality forged blades) useless. Secondly, even the best models provide only an adequate edge. If you don't mind replacing your knives every few years and are happy with the edge they give you, they are an option. But a much better choice is to...
Method 2: Send it out to a professional. This is a good option—provided you have a good knife sharpener living nearby, and are willing to pay to have the services performed. If you plan to sharpen your blades a dozen or so times a year as I do, this can get quite expensive. All but the best pros also use a grinding stone, which again will take away much more material than is necessary from your blade, reducing its lifespan. Want to forge a stronger relationship with your blade? Then you'll want to...
Method 3: Use a Sharpening Stone. The best method by far. 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. The only problem? It takes a little know-how.
That's where the slideshow above comes in. Get yourself some water stones, follow the instructions, and practice. You won't believe the difference a sharp knife can makes in your cooking.
Shopping and MaintenanceWhen 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 a stone 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.
About the author: J. Kenji Lopez-Alt is the Chief Creative Officer of Serious Eats where he likes to explore the science of home cooking in his weekly column The Food Lab. You can follow him at @thefoodlab on Twitter, or at The Food Lab on Facebook.