Sharpening Your Knives Incorrectly Can Damage Their Blades. Here's How to Do It Right.

New York Times

5 days ago

Before you sharpen your knife, it's important to know its material, its unique shape, and the angle in which to sharpen it.
The material determines how often you have to sharpen a knife, the difficulty of the task, and what type of sharpener you should use.
Chelsea Miller, a knife forger whose knives have been used in the dining rooms of Michelin-starred restaurants like Eleven Madison Park, explained, 'Carbon steel or high-carbon steel knives are generally easier to sharpen at home, whereas stainless steel knives — the most common manufactured type — are more difficult to sharpen freehand.' (Freehand sharpening is when you sharpen a blade without a guided system and instead use something like a whetstone or a manual, handheld sharpener. These methods usually don't offer the ability to adjust the angle.) Knowing the type of steel a blade is made from helps determine how frequently it needs to be sharpened. Michael Hession/NYT Wirecutter
High-carbon steel knives contain a higher carbon content than stainless steel, which generally makes them harder, stronger, and easier to achieve a keener edge than stainless steel knives. High-carbon steel knives are also easier to sharpen than stainless steel ones; it takes less effort to remove metal during sharpening due to its iron-carbide-rich composition. But they may require more routine maintenance since they're also less wear-resistant and can develop patina over time.
And then there's high-carbon stainless steel, which we recommend in our guide to the best knife sets. It combines the best aspects of high-carbon steel and stainless steel in one, so it's strong, able to hold an edge well, and less prone to rusting, but it's typically pricier. You can expect to have to sharpen it less frequently than a high-carbon steel blade.
Once you know the blade's material and how often you need to sharpen it, you can move on to determining the blade's shape and angle, so you can ensure the knife maintains its unique qualities to perform its intended job after it's sharpened. Navigating sharpening instructions is easier when you know the anatomy of a knife. NYT Wirecutter
There are two key blade factors to consider before you start sharpening: its grind (the cross-sectional shape) and edge (the shape of the cutting surface, or the bevel).
The most common kitchen blade grind is flat ground; that means the blade, generally speaking, tapers from the spine to the edge, and the cross-section forms a V- or a wedge-like shape, much like our budget-pick chef's knife, the Victorinox Swiss Classic Chef's Knife. (For a true full-flat grind knife, opt for a Japanese gyuto knife, like our runner-up chef's knife, the Tojiro F-808, which has a much thinner V-shaped blade than that of Western-style chef's knives.)
Another popular grind is hollow ground, a blade with a concave edge that, depending on the knife, can start on the edge and slope all the way up to the spine. This isn't as popular among kitchen knives, but is common among pocket knives, like our top pick, the CRKT Drifter.
The most common cutting edges among kitchen knives are typically V-edge (symmetrical edge bevels that form a 'V' shape) and compound beveled edge (a V-edge featuring multiple-edge bevels, like double bevels, which enhance cutting performance), such as the Tojiro F-808. Western knives usually have double bevels, meaning both sides of the blade angle towards the center. While many Japanese knives typically feature a single bevel, where one side of the blade is angled and the other remains flat, double-bevel variations are available as well, like the F-808.
Sharpening a knife — especially one designed for a specific task — at the wrong angle can severely alter its performance. 'Say you're using a boning knife whose angle was manufactured for that task, and you start sharpening it to another angle — like one more geared towards cutting vegetables rather than deboning a fish — you can completely change the angle and its performance,' Miller said.
You can generally find the appropriate angle to sharpen a knife via the manufacturer, either on their website or in a booklet provided at the time of purchase. However, if the information is unavailable, Miller recommends following general guidelines based on the shape of your knife. Most standard types of knives — like a chef's knife or paring knife — share similar angles regardless of the manufacturer.
Miller also recommended examining an edge by carefully holding a knife straight out in front of you, perpendicular to your eyes, and getting a good look straight down the knife's edge. She said you should analyze from tip to heel and from heel to tip to get a better idea of the adequate sharpening angle. Carefully look down the knife's edge to analyze the blade's angle. Repeat the process from tip to heel and heel to tip. (Squinting one eye can help make it easier to see.) Maki Yazawa/NYT Wirecutter