A trusty kitchen knife is to a chef what a sword is to a samurai, and both men keep their blades on point. Hence, should you take your cooking skills to the next level, you’ll need to know how to sharpen a knife. It might sound easy at first, but even the most seasoned of sharpeners will tell you there’s always room for improvement. And while electric blade sharpeners or sharpening steel rods seem like an effortless way to go, true chefs prefer a good old-fashioned whetstone, which offers more angle control and goes easier on the blade. Naturally, learning how to sharpen a knife on a whetstone takes a little more practice, but to champion the skill is to be a true master of your culinary domain. Here’s how to sharpen a knife for all the aspiring warriors out there.
This article is part of our Good Eating Series.
Gather Your Tools
Before you can get sharpening the old fashioned way, you’ll need the right tools. Thankfully, it’s not a long shopping list. First and foremost, you should seek out a quality chef’s knife and a sharpening whetstone. You’ll also need a sharpening stone base for mounting the whetstone, a sharpening stone fixer for smoothing the whetstone, and a dressing stone (also known as a nagura) to erase streaks from your whetstone or create a polishing slurry for your finishing stone.
What Exactly is a Whetstone?
Put simply, whetstones are stones used for sharpening knives. They come in a range of sizes, shapes, prices and materials. Because some knives need more sharpening than others, whetstones are commonly broken down by levels of grit and coarseness. Rough whetstones have less grit and more coarseness–they’re best used for blades that are especially dull or even chipped. Medium whetstones–the most common type used during the first step of knife sharpening–have a grit count that ranges from 800 to 2000. Finishing whetstones have the highest grit count (3000 or more), and they perform as described by eliminating the bumps or ridges that remain after sharpening.
The more expensive the whetstone, the harder (and better) that stone will be. Look for a $60-$70 USD price tag and you’re on the right path. There are also double-sided sharpening whetstones, which have a medium whetstone on one side and a finishing stone on the other. These are great for both beginners and those sharpening at home. Again, a quality example will generally fall in the $70 USD range.
A good, working whetstone retains a flat surface. Naturally, the more you use the whetstone the more the surface gets compromised. That’s why it’s important to use your sharpening stone fixer to resurface or flatten the whetstone, keeping it smooth and even.
How to Sharpen a Knife
To properly sharpen a knife, you should perform the following steps:
- Lubricate your whetstone. Soak both rough and medium whetstones in water for 20-30 minutes before using them. Do not, however, soak the finishing stone, which breaks down with greater ease. Instead, rinse the surface of a fine-grit stone and rub the dressing stone along that surface to create a type of polishing mud or slurry. Use the slurry on the finishing stone.
- Mount the whetstone. Put the sharpening base on a flat surface and put the whetstone on top of the sharpening base. Remember, you only need a rough (i.e. low-grit) stone if the blade is really dull. Otherwise, a medium whetstone will suffice.
- Hold the knife with the edge facing up. To hold the knife, you want your thumb on the spine, your index finger on the heel and the edge facing upward. The blade should be lined up with your arm.
- Place the bevel of the edge against the whetstone at an angle. For any given blade, there will be an adjustment period where you find the optimal angle.
- Properly position your free hand. Put the index and middle finger of your free hand atop (not at) the tip of the blade.
- Apply pressure and swipe. Swipe the blade along the whetstone as if pulling the blade toward you.
- Release pressure and repeat. Release pressure and slide the blade back to the starting point. Then apply pressure and swipe the blade back toward you.
- Continue swiping. Remembering only to apply pressure when swiping down, repeat the motion. Do not apply pressure when swiping upward or else you’ll damage the stone. Maintain a consistent, steady speed. With each successive swipe, crawl the index and middle finger down the blade toward the heel. You should also be counting the number of swipes so you can apply the same number on the flip side.
- Join forces at the heel. When the middle and index finger of your one hand reach the heel, they should meet the other index finger, which was there the whole time and can be now used for support.
- Stop and feel the opposite edge of the knife. Using your finger, touch along the edge of the blade. You should feel a minor ridge.
- Flip the knife. Turn the knife over. The edge is now facing downward.
- Re-position your fingers. This time around, the hand that’s holding the knife should have the index finger on the spine and the thumb at the heel.
- Redistribute pressure when swiping. Since the edge is now facing down, you should apply pressure when swiping away from you, not toward you. Enact the same amount of swipes as you did on the first side.
- Feel the side of the blade. You should once again feel for bumps, aka the burr.
- Use a finishing stone to polish off the burr. You’ll know you’re done polishing when the burr has been removed from the blade’s edge. To confirm, pinch the edge of the blade and pull away to feel for bumps.
- Test the edge by slicing something. If the blade can slice through a tomato without rumpling the skin, or a sheet of regular white paper without getting stuck, then it’s been properly sharpened.
- Air dry the stones. You can either leave your rough/medium whetstones in water for later use, or air dry them before putting them away. Finishing stones, however, must be air dried after use, otherwise they’ll crack. And while towel drying is indeed tempting, it can lead to mold. Hence, air drying is the way to go.
How to Sharpen a Knife Using a Honing Rod
Also known as “steel”, honing rods are commonly used to sharpen blades in between official whetstone sessions. They’re effective for realigning the blade’s metals by smoothing out minor abrasions. To use a honing rod, perform the following steps:
- Gripping the honing rod in your non-dominant hand, point the rod away from your body at any angle. Make sure the tip of the rod is positioned above the rod handle.
- Hold the knife in your dominant hand. Keep four fingers on the knife handle and your thumb on the spine, away from the blade’s edge.
- Place the knife at approximately a 20° angle on the holding rod. You should make sure you maintain the same exact angle throughout the entire process.
- Slide the knife across the top half of the honing rod, moving from heel to tip. Remember, you want to maintain the same angle the whole time. Also, by “top half of the honing rod”, we mean the half facing upward. Start at the heel of the blade and swipe toward the top of the blade.
- Keeping the same angle, sweep the knife across the bottom half of the honing rod. Do the same motion as you did at the top half. This completes one revolution.
- Perform 6-8 revolutions per knife.
How to Sharpen a Knife Using a Coffee Mug
Quick and easy (though probably not recommended by experts) is the method of sharpening a knife using the surprisingly rugged ceramic of a overturned coffee mug. Here’s how:
- Turn the mug upside down so that the bottom is facing upward.
- Keeping approximately a 20° angle, and moving heel to tip, swipe one side of the blade across the mug’s ceramic grit. Perform this motion several times.
- Flip the knife and perform the same process on the other side. Remember to maintain the 20° angle.
- Switch sides of the blade per swipe only for the last two to three swipes.
- Use a honing rod to smooth out any remaining kinks, burrs, or abrasions.
This article is part of our Good Eating Series.