Electric Knife Sharpeners

Published November 1, 2006.

Overview:

Even the most expensive, well-made knives lose their sharpness quickly when used regularly. And it doesn't take months, or even weeks: A knife can go dull in just a few minutes, especially if you're cutting through tough materials, such as bone.

What's the best way to maintain that snappy edge that makes light work of chopping and slicing? First, it's important to note that there's a difference between tuning up a relatively sharp knife and sharpening a dull knife. A so-called sharpening steel, the metal rod sold with most knife sets, doesn't sharpen at all: It's a tune-up device. As you cut with a sharp knife, the thin cutting edge of the blade can actually turn to the side, making your blade seem duller than it is. Running the knife blade over the steel, as most professional chefs do each time they're about to use a knife, simply realigns that edge and makes it straight again. It can't reshape a truly dull blade that's rounded and worn down. That's when you need a sharpener that can cut away metal and restore the standard… read more

Even the most expensive, well-made knives lose their sharpness quickly when used regularly. And it doesn't take months, or even weeks: A knife can go dull in just a few minutes, especially if you're cutting through tough materials, such as bone.

What's the best way to maintain that snappy edge that makes light work of chopping and slicing? First, it's important to note that there's a difference between tuning up a relatively sharp knife and sharpening a dull knife. A so-called sharpening steel, the metal rod sold with most knife sets, doesn't sharpen at all: It's a tune-up device. As you cut with a sharp knife, the thin cutting edge of the blade can actually turn to the side, making your blade seem duller than it is. Running the knife blade over the steel, as most professional chefs do each time they're about to use a knife, simply realigns that edge and makes it straight again. It can't reshape a truly dull blade that's rounded and worn down. That's when you need a sharpener that can cut away metal and restore the standard 20-degree angle of each side of the edge.

To reshape the edge of a dull knife, you have a few choices, depending on the amount of effort, skill, and money you want to invest. You can send it out (inconvenient, even if you can find someone to do it). You can use a whetstone (very difficult for anyone but a professional). But the best option for most home cooks is to buy a tool (either electric or manual) that does most of the work for you.

Most sharpeners, both electric and manual, start their work with a coarse material and progress through stages of finer material to polish the edge. In general, the hardest material is diamond, followed by tungsten carbide, followed by high-alumina ceramic, followed by steel. Hardness isn't everything, though; the material is only as good as the angle of the knife being swiped against it, so the design of the sharpener is important. Some models guarantee that even an inexperienced user will get the right angle; other models make this more a matter of chance.

Most of the electric sharpeners we found to be up to the job. They did differ on how quick and easy they were to use. In addition to taking less time and trouble to reach a fine edge, newer models feature spring-loaded blade guides that allow no ambiguous wiggle room as they hold the blade against the sharpening wheels at the proper angle, replacing the trickier magnetic guides on older models. The sharpening wheels on newer models also reach closer to the edge of the machine, ensuring that the sharpening extends all the way to the end of a knife.

Should you bother buying a manual knife sharpener? The better options will help you maintain new knives and are fine with moderately dull blades. But be prepared to pay a professional to handle your more challenging sharpening needs. In the long run, an electric sharpener is a good investment, if you can make the initial cash outlay. If not, pick up a cheap manual sharpener. The best ones are far superior to steeling rods and will keep many of your knives in decent shape.

Methodology:

We tested six electric knife sharpeners and evaluated them according to the criteria below.

STROKES TO SHARPEN

We used new 8-inch Victorinox Forschner Fibrox chef's knives (test kitchen favorites) dulled to a uniform level on a 220-grit whetstone. We sharpened the dulled knives according to manufacturer instructions, counting the number of strokes. (Note: The numbers are an average based on results from multiple testers and may vary based on the skill level of the individual operator.)

PERFORMANCE

We tested the dulled and sharpened knives by cutting a sheet of paper, cutting thin slices of tomato, and cutting fresh basil into a chiffonade (fine strips). Scores of good, fair, or poor were assigned for each test.

NOTCH REMOVAL

To see if the sharpeners could rescue damaged knives, we used a diamond slipstone to cut two 1/16-inch notches (one near the heel, the other near the tip) in each blade and then attempted to remove the notches with the sharpeners. We noted the number of strokes needed to remove both notches.

EASE OF USE

Factors include whether operating the device was easy and comfortable, instructions were clear, and overall time and steps necessary to sharpen were reasonable.

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  • Product Tested

    Results Key:

    Good ★ ★ ★ Fair ★ ★ Poor
  • Prices are subject to change.
  • Highly Recommended - Winner

    Chef'sChoice Model 130 Professional Sharpening Station

    This quiet model is the Rolls-Royce of sharpeners. Spring-loaded blade guides make sharpening foolproof. One slot works like a sharpening steel but removes all guesswork from the usual steeling motion.

    • Ease of Use ★★★
    • Performance ★★★

    $139.99

    BUY NOW Amazon
  • Recommended

    Chef'sChoice Model 120

    Very easy to operate; spring-loaded blade guides make sharpening foolproof. Knife seems to "fall" somewhat jarringly into first slot.

    • Ease of Use ★★★
    • Performance ★★★

    $129.95

    BUY NOW Amazon
  • Recommended with Reservations

    Chef'sChoice 110 Electric Knife Sharpener

    Does the job at a reasonable price, although somewhat noisily. Instructions are a bit confusing and magnetic guides could control blade angle more easily. Grinding elements are set in from edge of machine and miss the heel on knives.

    • Ease of Use ★★
    • Performance ★★★

    $84.95

  • Recommended with Reservations

    Presto EverSharp 8800

    Very loud, and stalled when testers applied any pressure. Appeared to scuff blades.

    • Ease of Use
    • Performance ★★

    $39.95

  • Not Recommended

    Waring PRO KS80

    Grinding wheels on this large, quiet machine are set in too far from end of slot, so user can’t hone entire blade edge. Knife dropped onto wheel, causing "scoop" to develop near heel end.

    • Ease of Use ★★
    • Performance ★★

    $99.95

  • Not Recommended

    Kershaw Electric Knife Sharpener

    Loud, "nerve-wracking" metallic noise. Grinding action sharpened at tip and heel of knife but not in middle, eventually ruining our knife. Crucial operation instructions found only on DVD. Can only operate two minutes at a time.

    • Ease of Use
    • Performance

    $59.95

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