Should you sharpen your ceramic knives?

If you’re reading this, you know something about ceramic knives — either you have some and are realizing that they do, in fact, get dull after some use, or you’re thinking about buying some and want to know what the upkeep is going to be like. The ceramic versus steel knife debate is not the purpose of this article, but stainless steel knives will be mentioned, for comparison, when it comes time to discuss sharpening. Ceramic blades are often touted as the blade that never dulls, but that is far from true. Everyone knows that stainless steel knives need to be sharpened now and then, but can you sharpen ceramic knives, too? And if so, how do you do it at home?

The problem

Not many people send their knives out to be professionally sharpened; not only is pro knife sharpening expensive, but it’s also inconvenient. No one really wants to package and ship out their knives and break out the spare set while they’re gone.

So, instead, do you sharpen a ceramic knife at home the same way you would a stainless steel knife? The short answer is no. The issue that some people have with ceramic blades is that they are very brittle because they are so hard. On the scale of hardness, ceramic is a 9.5, whereas steel is a 6.5. This means that if you press too hard on the side of a ceramic blade, it could break with ease, while a steel blade will bend, not break. The second main issue is that the only material hard enough to sharpen ceramic is diamond, which comes in with a hardness of 10.

The solution

If you have experience sharpening steel knives with a sharpening stone, you have a head start in the game of sharpening ceramic blades. The main differences in sharpening ceramic versus steel blades are the technique you use and where you hold the knife. If you put pressure on the blade incorrectly (laterally), you could snap the blade. To counter the possibility of applying too much pressure, the way to hold the knife blade is with both hands (when sharpening steel blades, typically one hand holds the knife and one hand holds the stone). The goal is to apply light force consistently with your fingers across the blade’s length and ensure that there is zero flex in the blade. The direction you sharpen does not matter; just do whatever you’re comfortable with while maintaining the blade’s proper position on the stone. Keep in mind that the blade is not going to give like a steel blade does when you sharpen it.

What you need

If you’re going to use and maintain ceramic knives, it is wise to invest in a diamond sharpening stone. Technically, you can use any stone you have, but diamond is harder than other materials and, therefore, will demand less work to remove material. Less work means fewer chances to snap the blade. As with sharpening steel, start with large grit and work your way toward a small grit. Four steps are best for ceramic, whereas only two steps are needed for steel. Also, no honing is necessary for ceramic blades. That’s the main advantage to them: Edge retention.

If you don’t feel comfortable manually sharpening your ceramic knives, you can purchase an electric knife sharpener. Just be sure to check to see if the model you like can handle ceramic — many models have abrasives on the sharpening wheels that will damage ceramic blades. Also, don’t be misled by an electric sharpener that says it has honing rods that are “ceramic knife sharpeners,” as this likely means the rods themselves are made of ceramic, not that it is meant to sharpen ceramic knives.

Now that you know that it takes a bit more work to maintain ceramic knives, the choice is yours. Edge retention is definitely ceramic’s main advantage, but the major downfall is they are easy to break while sharpening. If you already have a knife block full of ceramic knives, follow the guidance above to sharpen them up before you use them next. A bit of practice with a decent diamond stone, and you’ll be a knife-sharpening pro in no time.

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