Our Manual Knife Sharpener performance TestMaximum Sharpness

Anh Ngo
Lap Vo
Test Lead
Nguyen Ntk
Visual Specialist

Exactly how sharp can your knives get with a handheld sharpener? This test, performed on all the sharpeners we come across, is designed to find out the highest level of sharpness you can achieve with each device within 6 minutes.

Why Maximum Sharpness Matters

Some sharpeners go beyond others in terms of how sharp an edge they can produce. A device that can go higher on the Practical Knife Sharpness Scale allows you to handle a wider range of food prep tasks. A sharper knife also offers the support you need to finish your food preparation tasks quickly and with better precision.

Maximum Sharpness

While sharpening may require significantly more time as you move up the scale, a keener edge will be serviceable for longer, thus requiring less frequent maintenance.

Therefore, although you can’t always expect razor-like results out of handheld sharpeners, this test is still worth considering before you buy a device. 

Since excellent sharpness is a plus, not a must, we assigned the maximum sharpness test 20% of the Performance score.

What’s New in V1.1

Most sharpener brands promise noticeable improvement ‘within a matter of seconds.’ We have another test for the time it takes to bring a knife to workable sharpness, but to find out the maximum level each device could give us, we use 6 minutes as the benchmark. A shorter duration may not be enough to reveal the device’s potential. A longer one would defeat the purpose of a ‘convenience sharpener.’ 

In our first version of the test, we allocated the 6 minutes equally among the sharpening stages on a device. For example, if a sharpener has three stages, we spent 2 minutes on each. 

We eventually realized that it’s more effective to focus on sharpening the knife on the coarsest slot, and in this new version of the test, decided to do just that. We allocate 30 seconds to the prep slot and 30 seconds on each of the hining slots, if applicable.The remaining time of the 6 minutes is spent on the coarsest slot to get the knife as keen as possible.

Test Equipment

Here’s a list of what we use for the test.

  • Sharpening device
  • 8-inch, 20-degree chef’s knife 
  • Sandpaper
  • A4 paper
  • Stopwatch app
  • Lemons, tomatoes, chicken breasts with skin on, and beef tendons, all fresh and raw.

The food items are those from the Practical Knife Sharpness Scale. We pick items starting from the highest Serviceable Level (Level 6 - Lemons) going all the way up to the top (Level 9 - Beef tendon).

The Testing Process

Here are the steps we take for the test.

Step 1. We blunt a knife by running it across sandpaper for 60 seconds and test it on a piece of A4 paper to make sure the desired bluntness is achieved. We try to make each test knife equally blunt.

Step 2. We run the knife through the sharpener for about 6 minutes, following the slot order as it is on the device. We spend 30 seconds on the prep or polish slots and the remaining time on the sharpening slot. 

Step 4. We try the knife out on the food materials, progressing up the Practical Knife Sharpness Scale in order, and note down the results.


We base our scoring on an adaptation of the Practical Knife Sharpness Scale.

Since beef tendon is the toughest food on the scale, a device that can bring your knife from dullness to that level gets 10 points. Every step below that on the scale marks a deduction of 2 points. Each extra swipe translates to a 1-point deduction. 

Devices that failed to bring the test knife to Level 6 (Lemon) got 0 points.


Food Item


6 -

Lemon, 2 swipes



Lemon, 1 swipe


7 -

Ripe tomato, 2 swipes



Ripe tomato, 1 swipe


8 -

Chicken breast with skin, 2 swipes



Chicken breast with skin, 1 swipe


9 -

Beef tendon, 2 swipes



Beef tendon, 1 swipe


Test results

Showing 9 of 9 Manual Knife Sharpeners tested
Images & Video
Maximum Sharpness
Sharpening TimeSharpness LevelPicturesVideoTest Methodology
Gorilla Grip Manual Knife Sharpener Review
Gorilla Grip
6 minutes8 (chicken breast with skin, 1 swipe)
Gorilla Grip Maximum Sharpness Achieved videov1.1
Sharpal Knife Sharpener Review
6 minutes8 (Chicken breast with skin, 1 swipe)
Sharpal Maximum Sharpness Achieved videov1.1
Cubikook Manual Knife Sharpener Review
6 minutes8 (Chicken breast with skin, 1 swipe)
Cubikook Maximum Sharpness Achieved videov1.1
Priority Chef Manual Knife Sharpener Review
Priority Chef
6 minutes 8 (chicken breast with skin, 1 swipe)
Priority Chef Maximum Sharpness Achieved videov1.1
Zwilling Manual Knife Sharpener Review
6 minutes8 - (Chicken breast with skin, 2 swipes)
ZWILLING Maximum Sharpness Achieved videoZWILLING Maximum Sharpness Achieved video 1v1.1
Kitchellence Knife Sharpener Review
Kitchellence 3-Stage
6 minutes8 - (chicken breast, 2 swipes)
Kitchellence Maximum Sharpness Achieved videov1.1
Amesser A-65 Manual Knife Sharpener Review
Amesser A-65
6 minutes8 - (Chicken breast, two swipes)
Amesser A-65 Maximum Sharpness Achieved videov1.1
Chef’s Choice 4643 manual knife sharpener Review
Chef's Choice 4643
6 minutes 7 (Ripe tomatoes, 1 swipe)
Chef’s Choice 4643 AngleSelect Maximum Sharpness Achieved Videov1.1
Longzon 4-stage Manual Knife Sharpener Review
Longzon 4-stage
6 minutes7 (ripe tomatoes)
Longzon Maximum Sharpness Achieved videov1.1
Showing 9 of 9 Manual Knife Sharpeners tested