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Searching for the Best Electric Knife Sharpener

By Lisa McManus Published

Sharp kitchen knives make cooking much easier. So which sharpener should you use?

The first time you slice into food with a truly sharp knife, it’s eye-opening; you feel like your skills just leveled up. Our favorite tool for keeping our kitchen knives sharp has long been an electric knife sharpener because a good one can bring the dullest, most damaged blade back to life and then keep it in prime shape with quick touch-ups. You don’t need special skills or a lot of time if you have the right electric sharpener, which means that you can take care of your knife in minutes and get back to the real goal: making something good to eat. 

Our previous favorite, the Chef’sChoice Trizor 15XV Knife Sharpener, has some new competition, so we bought a fresh copy of our winner and six rivals, all priced from about $37 to about $160. We set out to find machines designed to sharpen blades to 15-degree angles because our favorite chef’s knife, the Victorinox Swiss Army Fibrox Pro 8" Chef’s Knife, is sharpened to a 15-degree angle on each side of its blade. However, Presto, the manufacturer of two popular sharpeners included in our lineup, did not reveal this information, saying only that its machines produce the “optimum” angle. A sharpener from another manufacturer sharpens blades to 17 degrees, but the manufacturer sells separate accessories to sharpen blades to 15- or 20-degree angles. In this case, given that it was only a 2-degree difference, we decided we would not test its 15-degree accessory unless this sharpener beat the rest of the lineup.

We assigned one copy of our favorite chef's knife to each machine throughout testing.

We put all the sharpeners through their paces, using each machine to sharpen the blades of brand-new copies of our favorite chef's knife that we’d dulled by dragging them over a whetstone, repeating the dulling-and-resharpening test a total of four times. We assigned one copy of the knife to each machine throughout testing. To evaluate the results after each sharpening, we sliced through sheets of copy paper, our standard sharpness test; used an industrial sharpness-testing machine that assigned a numerical score to the sharpness; and finally circled back to the real world by slicing ripe, juicy tomatoes. 

With the heel of the blade at the top edge of a sheet of copy paper, we slice downward, letting the blade pass through the paper from heel to tip. Here, a sharp knife easily slips through the paper with almost no resistance, but dull blades feel slow and "draggy." Any rough spots along the blade will catch and rip the paper.

 

To see if the machines could handle chef’s knives made with different designs, metal composition, and blade hardness, we also dulled and sharpened a single copy of a Japanese carbon-steel knife that we recommend, the Misono Swedish Carbon Steel Gyutou, 8.2". And to see whether the sharpeners could repair damage, we used a tool to drill small notches in all the Victorinox blades to simulate chips you can get on your knife when cutting very hard or frozen food. Throughout testing, we evaluated how easy the sharpeners were to operate, as well as how much time and effort we had to devote to bring our knives back to razor-sharp condition. We also noted whether the machines kept our countertops clean of metal dust and whether the knives’ blades or handles were damaged by the sharpeners.

How Electric Sharpeners Work

Electric sharpeners operate by rotating an abrasive sharpening material as you pass a blade along it to grind metal from the edge of the knife. Typically, the rotating sharpening material is set inside the body of the machine for your protection, and you pass the knife through one or more V-shaped slots that help you control the angle of the blade as it touches the abrasive. The sharpeners in our lineup contained diamond, Sapphirite (a synthetic ceramic), or other ceramic-based abrasives in the form of disks or belts. They offered one of two sharpening methods: either you pass the knife through a series of slots in stages containing a range from coarse to fine abrasives, or you put it through a single stage while the machine varies the speed of the rotating abrasive. Both methods are designed to regrind and then polish a knife’s edge.

When Should You Sharpen and When Should You Hone?

  • Whenever you feel your knife is less sharp than it should be, try honing first. It pushes the cutting edge of the blade back into alignment while removing a small amount of metal from the blade's edge. By honing periodically you can extend the time between sharpening sessions. If you don't own a hone, you can use the final, fine-grit slot of our top-rated manual and electric sharpeners for touching up the blade; this would serve as a stand-in for what a honing rod can do. However, if you find that honing the blade doesn't make much of a  difference, it's time to get out the sharpener. The angle control, overall power, and progressive stages (including a final polish) offered by our top-rated electric sharpener can bring even the dullest blade back to a brand-new, razor-sharp condition in minutes.

To test the knives' sharpness, we sliced ripe tomatoes after sharpening each knife.

The Most Important Factor: How Sharp Can It Make Your Knife?

We judged the sharpeners on a few key factors. First and foremost, if they couldn’t make a dull blade truly sharp again, any other features really didn’t matter. Three of the machines never restored the razor sharpness of the brand-new blades—no matter how long or carefully we used them. Four other models did have that capability.

Testing Sharpness

  • We used a device called the Edge-On-Up Industrial Edge Tester to help evaluate the effectiveness of all the electric knife sharpeners in our lineup. This device works by stringing a special kind of standardized, calibrated thread between two posts on a type of scale. When you carefully slice through the thread with a newly sharpened blade, the machine registers the force required in grams, giving a numerical score that can be used to compare the relative sharpness of edges. 

     

    While we appreciated this quantitative measurement of sharpness, which mostly tracked nicely with our usual evaluations of sharpness such as slicing copy paper and ripe tomatoes, the downside of the industrial sharpness tester is that it measures only one point along the blade, precisely where you cut through the thread. In the course of testing we discovered that a few of the sharpeners had trouble creating a consistently sharp edge along the entire length of the blade, which the paper test revealed clearly. When you draw a blade through paper from heel to tip, it’s remarkably easy to feel any snags or dull spots as the blade catches and rips paper instead of slipping through smoothly like a truly well-sharpened knife.

Sparks flew when we sharpened a carbon-steel knife on the Presto Professional EverSharp Three Stage Electric Knife Sharpener's abrasives, which are made of Sapphirite, a synthetic ceramic. While the manual warned this might happen, we still found it a bit alarming.

 

That said, consistency was a problem with one of the four. The Work Sharp Culinary E5 was undoubtedly the most compact, easiest, and fastest to use—we simply pushed a button to start an automatic 90-second cycle and then drew the blade repeatedly through a single pair of left and right slots—but the outcome wasn’t always optimal. We often discovered a rough spot along part of the edge during our paper-slicing test. These uneven results may have been due to the design of the slots: Since they’re wide, they didn’t help control the blade angle; instead, we had to remember to consistently lean the blade away from the rotating abrasive and toward a leather-lined outer wall, and the direction in which we had to lean the blade was different depending on the slot we were using. We usually had to run the sharpening cycle more than once to get a uniformly sharp blade. We preferred models that gave us dependable sharpening that was consistent from blade heel to tip, every time. For the same reasons, this model did a less-than-stellar job sharpening our carbon-steel blade. We also discovered after testing that this sharpener had cut into our favorite chef’s knife’s handle where it joins the blade, leaving it rough and damaged, though this might be avoidable if you are aware of this potential and are very careful.

A tester passes a knife through the left and right slots of the Work Sharp Ken Onion Edition sharpener, which features exposed rotating abrasive belts.

 

Work Sharp Knife & Tool Sharpener Ken Onion Edition presented the opposite situation: It was by far the most effective sharpener in our lineup, providing the utmost control and flexibility, but because its rotating abrasive belt is exposed, it was daunting to use and it made a mess of our work area, spraying metal filings and grit everywhere. It belongs on a tool bench rather than the kitchen counter. That said, if you’re up for handling a semi-industrial tool and have a pair of protective goggles handy, this is your sharpener, and it’s capable of dazzling results. The package included five abrasive belts in a range of professional-grade materials and coarseness levels and a lot of information about how to use them to sharpen everything from kitchen blades to shears, hunting knives, and tools. You can set the edge angle from 15 to 30 degrees and precisely adjust the speed of the sharpener. One final note: With its exposed belt, this sharpener literally chewed off the front edge of our Victorinox knife’s Fibrox handle before we had time to adjust it.

Magnified close-ups show the edges of the same model of chef's knife sharpened on the winning Chef's Choice Trizor 15XV sharpener (left) and the Presto Professional EverSharp (right). The Chef's Choice model created a polished and smooth edge, while the Presto model gave the blade a jagged, "toothy" edge.

The Best Electric Knife Sharpener: Chef’sChoice Trizor 15XV Knife Sharpener

Our journey ultimately led us back to our previous winner, the Chef’sChoice Trizor 15XV Knife Sharpener. Once again, this three-stage machine was the most dependable and consistent sharpener of the lineup and the clearest in its instructions. The steps to achieving a sharp edge are detailed in the manual, and we recommend following them each time you sharpen, since they showed us precisely what to look for at each step before proceeding to the next.

When we followed the steps, we got an impressively razor-sharp, polished, and uniformly sharpened edge on even the dullest knife in about 2 minutes. It quickly removed all traces of the notch we cut to damage the blade, and it did a swift and superlative job restoring the carbon-steel knife’s edge, too. The narrow, spring-loaded slots made it simple to maintain the correct knife angle. The first two slots, one coarse and one medium, contain diamond abrasives that allowed us to easily power through the sharpening process, with each stage creating a slightly different-angled bevel on the cutting edge. The third slot contains a “stropping” disk made of a proprietary flexible plastic material with ultrafine diamond abrasives. Traditionally, strops for blades are made of leather, and their role is to remove burrs and polish cutting edges, leaving them extra-smooth and sharp. Any metal grit created by sharpening was collected neatly in a magnetic holding bin that was easy to empty (though it would take many months to fill with normal use). This sharpener can also be used to maintain other knives in your kitchen, including paring and boning knives, single-bevel traditional Japanese-style knives, steak knives, and even serrated blades (in this case, using only the stropping disk in stage three).

This model shares some of its characteristics with a slightly less expensive version, the Chef’sChoice 315XV Knife Sharpener, which gave us almost equally good results in about the same time frame, so we’ve named it our Best Buy. Like the Trizor, this model also can sharpen a variety of kitchen blades, not just chef’s knives. Where the two models differ is in the number of sharpening stages—the Trizor has three, the model 315XV machine has two (the medium-abrasive and stropping disks). Since one less bevel provides less blade support, the two-beveled blade edge created by the less-expensive model may require a bit more frequent sharpening over time. However, how often you need to resharpen can also depend on the hardness of your cutting board, what you are cutting, and how you use your knife, so it’s difficult to say whether having two or three bevels makes a perceptible difference. We did come to the conclusion that the Trizor put a slightly more smooth, razor-sharp edge on knives, particularly the carbon-steel blade, but either model will help you sharpen quickly and get right back to successful cooking.

Equipment Review Best Electric Knife Sharpeners of 2021

Sharp kitchen knives make cooking much easier. So which sharpener should you use?

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JC
JOHN C.
16 days

Absolutely the best chicken ever, even the breast meat was moist! It's the only way I'll cook a whole chicken again. Simple, easy, quick, no mess - perfect every time. I've used both stainless steel and cast iron pans. great and easy technique for “roasted” chicken. I will say there were no pan juices, just fat in the skillet. Will add to the recipe rotation. Good for family and company dinners too. I've done this using a rimmed sheet pan instead of a skillet and put veggies and potatoes around the chicken for a one-pan meal. Broccoli gets nicely browned and yummy!

Absolutely the best chicken ever, even the breast meat was moist! It's the only way I'll cook a whole chicken again. Simple, easy, quick, no mess - perfect every time. I've used both stainless steel and cast iron pans. great and easy technique for “roasted” chicken. I will say there were no pan juices, just fat in the skillet. Will add to the recipe rotation. Good for family and company dinners too.

MD
MILES D.
JOHN C.
9 days

Amazed this recipe works out as well as it does. Would not have thought that the amount of time under the broiler would have produced a very juicy and favorable chicken with a very crispy crust. Used my 12" Lodge Cast Iron skillet (which can withstand 1000 degree temps to respond to those who wondered if it would work) and it turned out great. A "make again" as my family rates things. This is a great recipe, and I will definitely make it again. My butcher gladly butterflied the chicken for me, therefore I found it to be a fast and easy prep. I used my cast iron skillet- marvellous!

CM
CHARLES M.
11 days

John, wasn't it just amazing chicken? So much better than your typical oven baked chicken and on par if not better than gas or even charcoal grilled. It gets that smokey charcoal tasted and overnight koshering definitely helps, something I do when time permits. First-time I've pierced a whole chicken minus the times I make jerk chicken on the grill. Yup, the cast iron was not an issue.