In the kitchen, a sharp knife is an extension of your hand. Knife care and maintenance are critical aspects of knife ownership. But as important as knife sharpening is, it’s surprisingly easy to let it fall by the wayside. Luckily, there is a nifty trick to sharpen a knife that does not require a whetstone or a trip to a sharpening service. All you need is a ceramic mug.

How to sharpen a knife with a mug

The technique is simple and works great in a pinch. Flip over a ceramic mug, grab your knife, and run the edge of the blade against the unglazed ring on the mug’s bottom at a 15- to 20-degree angle. Strokes work best, but you can also gently rub the bottom ring of the mug in small circles against the edge. A few strokes (or rubs), about 10 to 15 on each side will do the trick; the key is to make sure you count the number of strokes on each side for symmetry.  Once you’re done, you’ll find the edge much sharper than before.

Why it works

On the bottom of most ceramic mugs is an unglazed ring. (This prevents them from sticking to the shelf of the kiln during firing.) When you run a knife edge on the unglazed ring on the mug’s bottom, its durability and its rough texture acts like a sharpening stone. You can also apply this same technique to the unglazed edges or bottoms of ceramic plates or bowls.

The difference between sharpening and honing

This technique doesn’t just hone your knife, it actually sharpens it. Honing works by straightening and smoothing the metal fibers in a knife’s blade. When you hone your knife with a honing steel, the metal fibers in the blade realign themselves when they come into contact with the steel. When you sharpen a knife, tiny bits of the blade’s metal are ground and shaved away, giving you a new edge. A ceramic mug doubles as an impromptu honing steel and sharpening stone; and running your knife along the unglazed bottom ring will both hone and sharpen it.

How often should you sharpen your knives?

There isn’t a one-size-fits-all recommendation for how often you should sharpen your knives. The frequency at which you should sharpen them depends on factors such as the type of knife, how frequently you use them, and how hard you are on them. The type of knife work is also a factor. For example, butchery tasks, like breaking down whole chickens, lead to faster wear and tear. Food & Wine senior research strategist and knife expert John Somerall generally recommends sharpening your knives at least once or twice a year. Honing your knives should happen much more often, preferably before or after each use.

The next time you find your go-to kitchen knife squishing your tomato instead of slicing it, or find yourself saddled with a block full of dull knives at your next vacation rental, grab your morning coffee mug and start sharpening.