How to Properly Sharpen a Knife

Anna Borgman Jun 1, 2022

Before I began work as a full-time butcher, I had little interest in the intricacies of knife-sharpening. Even as a restaurant cook, I often did the bare minimum when honing the blade on my chef's knife. And because I usually only skinned a few animals each year, my hunting blade was, I now realize, dangerously dull. These days, however, I cannot afford to use dull knives. Each week at the meat shop, I skin and gut at least five beef, pigs, or sheep. When I am not on the kill floor, I butcher those same animals in the cutting room, using a boning knife and a hand saw. I wouldn’t be able to do any of these jobs without a razor-sharp edge, and in a meat shop, no one is going to sharpen your knives for you, so you'd better learn fast.

The Benefits of a Sharp Knife

While it may seem contradictory, a sharp knife is significantly less dangerous than a dull knife. A sharp knife misused can cause severe damage, but a dull blade can injure and maim even when used under best practices. Dull knives do not want to cut, which forces the user to apply greater pressure, increasing the risk for injury when the blade finally moves through the object and into an unsuspecting body part. Sharp knives require less force and will cut through a piece of meat quickly, reducing the risk of slippage and impalement.

I can report from experience that a sharp knife also reduces the risk for chronic injuries such as carpal tunnel, arthritis, and muscle strain. Butchering multiple animals every day for months with a dull knife will necessitate more than a trip to the masseuse. Permanent joint and muscle pain are risk factors for anyone working a manual labor job, but sharp knives can mitigate those risks for butchers. After thousands of cuts through meat, tendon, and around bones, it quickly becomes apparent how crucial a good edge is for maintaining physical and mental stamina throughout the day. The quality of the edge on your knife will be a product of both the type of knife you choose to use and the sharpening routine you develop in your practice.

Types of Knife Steel

There are two types of steel predominantly used for knives: carbon steel and stainless steel. The difference between stainless steel and carbon steel is the amount of chromium in the alloy. Stainless steel contains more than 10.5% chromium which provides corrosion resistance, making it simpler to maintain. With less than 10.5% chromium, carbon steel will rust without proper care.

These differences are crucial for understanding how the alloy content of your knife relates to its ability to stay sharp. Stainless steel will maintain an edge even after heavy use and can withstand a dishwasher cycle. However, stainless steel is not as hard as carbon steel, and can bend and warp under pressure or impact. You must clean carbon steel (never use bleach) and oil it after use to prevent rust, but if properly maintained, the extreme hardness of the carbon steel blade will hold an edge under heavy usage (though it can chip on impact).

Sharpening

A whetstone or sharpener is a block of abrasive material used to grind and sharpen a knife. Stones come in all shapes, sizes, and coarseness levels. A useful stone should have at least two sides with differing coarseness, namely a coarse side and a fine side. The coarse side removes metal by grinding and re-shaping an edge when it has become too dull. The fine grit side sets the edge and polishes it once honed and sharpened.

To use a whetstone, hold your knife blade against the coarse side at no more than a 25-degree angle and pull the blade across the stone using a sweeping motion to bring the entire cutting edge of the knife into contact with the stone from handle to tip. Repeat that motion until you begin to feel a burr on the side of the blade that is facing you. What you are doing is grinding the rounded secondary bevel of your knife into a new point. Once the old, rounded bottom edge meets the top edge, you’ll feel the burr, and then it’s time to turn the knife over and repeat those same motions a few times on the other side. The edge will now feel sharp but not smooth. Flip your stone over and repeat the same pulling and sweeping motion back and forth on each side of the blade until the burrs wear down and the edge is smooth and sharp.

Steeling or Honing

A honing steel is not a sharpener. That metal rod that came with your knife block will not help you if your edge is already dull. Steels realign a sharpened blade by removing microscopic metal burrs and straightening the edge, which will begin to roll to one side during use.

I keep a honing steel on my belt at work, which I use countless times while skinning animals and cutting meat. Each time my knife feels dull, I hold the blade against the steel at a 22-degree angle and drag the entirety of the blade against the steel. I then repeat that on each side back and forth about four or five times. A honing steel will readjust the edges of a sharp blade, but it will never sharpen a blade that is already dull. Until you feel comfortable with your steeling technique, make sure that your movements are slow and your pressure is minimal against the steel. Improper steeling can dull even a sharp knife, then you're back and square one, so it is essential to learn and practice correct steeling techniques.

Time and Practice

Proper sharpening and steeling techniques are hard to come by. Even some of the most experienced cooks and butchers do not know how to steel a knife correctly. The best way to practice both skills is simply through repetition. I suggest finding a few knives that you aren’t worried about ruining and just going to town sharpening them. Make mistakes, then find out what works and repeat it over and over again. The first knife you successfully sharpen will be a revelation, and your muscles and intact fingers will thank you for it.