The most effective technique for sharpening knives has not changed in centuries. Sharpening stones, oil stones or whetstones may use man-made materials impregnated with diamond, carbide or ceramic grit, or they can be made from naturally occurring stone. Some can be used dry, some work better with water, and others, particularly in the United States, work best if oiled with mineral oil. Sharpening steels surprisingly do not sharpen--they only straighten the blade and make it feel sharper.
To sharpen a one- or two-sided beveled blade, start with a coarse stone (about 180 grit) and remove any nicks in the blade's edge. Try to keep the blade at the angle of the existing bevel and slide it across the stone smoothly or in a circular motion with a steady pressure. Repeat until it feels smooth. Change to a smoother grit (320 to 360) and repeat the process, making sure you sharpen the entire length of the blade including the tip. Finish off and hone to its ultimate sharpness with a fine stone (600 to 800 grit). Use the stone with mineral oil, water or dry, according to the manufacturer's directions.
A sharpening steel is a poker-shaped tool used most often by chefs. The correct method is to hold the steel tip down on a board with the handle in the air. Position your knife at a 20-degree angle from the steel. Guess close to 20 degrees by starting with a 90-degree angle, cutting it in half with your eyes, then in half again. Pass the knife across the steel and repeat on the other side of the blade. Repeat about six times, making certain you pass both sides across the steel an equal number of times. This process will make the blade seem sharper because it straightens the edges that curl over microscopically with use.
Sharpening a Serrated Knife
Serrated knives are extremely hard to sharpen, and sharpening should not be performed too often. They do not have to be perfectly sharp because they work by rubbing the varied surfaces against the item being cut. Use a specialized rounded sharpener to sharpen a serrated knife. Each serration must be sharpened individually by passing the stone across each indentation. Alternatively, you can pass the knife over the stone in the same way. Either way, take care not to enlarge the serrations and do not sharpen the backs. A cone-shaped sharpening stone can also be used. Pass it through each serration and turn it at the same time.
Electric and Hand Knife Sharpeners
Electric and hand knife sharpeners most commonly found in kitchens have a handle and a slot to pass the knife through. They are popular because they are easy to use. You simply pull the knife through the slot repeatedly, making certain you don't lift it out before sharpening the tip. Inside the slot are two or more diamond or carbide stones. These sharpeners tend to scratch the knives. They work well at first but their effectiveness may wear off in time.
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