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Mueller 4-Stage vs. Zwilling 4-Stage Manual Sharpener Side-by-Side Comparison
Our Verdict
- Performance (50%)6.7/10
- Design (15%)9.1/10
- Ease of Use (35%)8.3/10
- Performance (50%)4.7/10
- Design (15%)7.5/10
- Ease of Use (35%)7.8/10
Both the Mueller 4-stage and the Zwilling 4-stage manual sharpeners feature a strong and sturdy build. However, the former offers better balance and stability during sharpening thanks to its broader base.
Note that while both sharpeners have four sharpening slots, the Mueller actually reserves three for kitchen knives and the remaining one for scissors. The Zwilling, meanwhile, assigns two slots for each type of knife, namely, standard and Asian.
Neither offered a particularly well-rounded performance. The former was quick and capable, though it was also rigorous on the knife’s edge. The latter produced a smoother edge but took too much time to sharpen.
All in all, the Mueller is the better choice because it’s faster, more effective, and easier to use— and that is what’s most important in a convenience sharpener.
Mueller 4-Stage Knife Sharpener’s Performance
- Sharpening Time to Cut a Lemon (35%)8.8/10
- Maximum Sharpness Achieved (20%)8.0/10
- Edge Smoothness (20%)4.0/10
- Material Retention (25%)5.0/10
- Sharpening Time to Cut a Lemon (35%)1.0/10
- Maximum Sharpness Achieved (20%)7.0/10
- Edge Smoothness (20%)7.3/10
- Material Retention (25%)6.0/10
Sharpening Time to Cut a Lemon
- Sharpening Time: 1 minute 15 seconds
- Cutting Feel: Swift and smooth
The Mueller isn’t the speediest of sharpeners, but it works fast enough. We put it through the lemon test twice, and it took 60 and 90 seconds respectively to complete the task. This is quite a reasonable time range, considering how dull we made the knife before testing.
Skipping the diamond rods won’t affect the result. We only used them to rid the knife edge of metal particles and make sure it was as smooth as it could be, but if you’re in a hurry, the ceramic rods alone would suffice.
- Sharpening Time: 3 minutes
- Cutting Feel: Slightly forced
The Zwilling is, sadly, one of the slower sharpeners even among its category. It took 180 seconds to sharpen a sandpaper-destroyed knife to the lemon-cutting level, and even then, the cutting motion didn’t feel completely effortless. Three minutes may feel like nothing if you’re used to working with a whetstone, but for a convenient device like this one, one would expect a much shorter time.
Maximum Sharpness Achieved
- Sharpening Time: 6 minutes
- Sharpness Level: 8 (Chicken breast with skin, 1 swipe)
After 5 minutes on Slot 2 and 30 seconds on each of the remaining slots, our test knife was able to cut through a raw chicken breast with the skin still attached. It did need a second swipe to sever the tough, slippery fat and skin, but this is the case for most devices.
- Sharpening Time: 6 minutes
- Sharpness Level: 8 - (Chicken breast with skin, 2 swipes)
While it failed quite miserably in the speed test, the Zwilling sharpener got decent results when given more time. The test knife passed the tomato test with flying colors and could cut through the muscle and runny skin on a fresh piece of chicken breast with two light and easy swipes.
We tried it on beef tendon too, which it took two heavy strokes to sever. The device was marked as failed for this level, but we think its efforts would be sufficient for most food prep needs.
Material Retention
- Sharpening Time: 1 minute
- Target Sharpness:
The Mueller is a disappointment when it comes to preserving edge integrity. We were horrified at the size and amount of swarf the sharpener churned out after every swipe on the tungsten carbide blades. It’s all or nothing with this slot: When it works, it shaves off as much metal as it can. When it doesn’t, your knife simply glides through it, untouched.
The icing on the cake is the obvious unevenness on the two sides of the edge. We can’t quite work out the reason for this, because its sharpening slots look exactly the same as the Longzon, which created a very nice edge in our test. We re-edged the test knife and tried again, and even replaced the test knife in case it was a faulty one, but the end result was the same.
- Sharpening Time: 1 minute
- Target Sharpness:
For the sharpness level it could achieve, the Zwilling shaves off way too much steel from the knife. We couldn’t help but shudder at the long curls of swarf coming out of the Coarse slot.
Most other devices employ ceramic rods for honing the knife, so even though this function comes in the form of blades on this sharpener, we really didn’t expect the ceramic to be so harsh on the knife edge.
Edge Smoothness
The diamond dust and ceramic rods didn’t seem to do much if anything to smoothen the edge: It came out rough with waves and small chips all across its length. I could see it with my naked eyes and feel the chips and small particles as I ran my fingers along the edge. The discrepancy between the two sides just tops it off.
Although the Zwilling peels a lot off the knife, we have to give it credit for the pretty edge it left. There are long and deep grooves along the edge—we could tell from the swarf alone—but overall, the edge is straight and consistent, and without visible chips or teeth.
However, with its ceramic blades chipped after only a few uses, we’re at best skeptical about the device’s ability to maintain delivery of this edge quality.
Mueller Knife Sharpener’s Design
- Build Quality (75%)9.1/10
- Grip (25%)9.0/10
- Build Quality (75%)7.8/10
- Grip (25%)6.5/10
What’s in the Box With the Mueller Scissors and Knife Sharpener
- The Mueller 4-stage knife sharpener
- Instruction manual
- Appreciation card & promotional leaflet
The Muller KS-4ST knife sharpener comes in a nice cardboard box. Included is a detailed user guide with safety notes and instructions on how to sharpen knives of different dullness levels.
- The Zwilling 4-stage sharpener
- Instruction leaflet
The Zwilling 4-stage sharpener comes protected by a plastic blister pack, with a simple instruction manual. The device is solid and heavier than most others.
Dimensions
- Length:9.3" (23.6 cm)
- Width:1.8" (4.6 cm)
- Height:3.1" (7.9 cm)
- Weight:8.6 oz (244 g)
- Length:9.3" (23.6 cm)
- Width:1.7" (4.3 cm)
- Height:3.1" (7.9 cm)
- Weight:11.2 oz (318 g)
Build Quality
The Muller sharpener appears to be made from decent-quality materials. There’s also little to complain about regarding the construction: Its parts align well and even when we dropped the device on the floor they stayed together like a one-piece tool. We don’t like its high center of gravity and prefer a more weighted base, but at the same time, we can’t deny how well it was put together.
While its design leaves a lot of room for improvement, the Zwilling is overall a robust, well-built sharpener. Its body feels rigid and solid, the frame and paddings are made of high-quality materials, and every part fits together nicely, leaving no gaps.
Unfortunately, the device’s weakness is its most critical part: the ceramic sharpening blades.
Normally, ceramic is used to make honing rods on pull-through sharpeners, but on the Zwilling, it’s employed in the shape of rectangular sharpening blades with their own delicate edges. The chipping we found on those blades after only a few days of testing proved that this break from the norm was an error of judgment. Obviously, being hard but brittle, the ceramic blades couldn’t withstand a rough steel knife edge.
Grip
- Material:ABS plastic and rubber
The Muller has a grip that’s proportional to its wide working section. It offers lots of space for those with large hands, and there are finger nubs that make it easy to hold on to. We also appreciate the rubber padding on the upper side of the grip: It’s soft and gentle to your palm while also creating useful friction against grease or moisture.
- Material:ABS, EVA
The Zwilling’s grip looks and feels fancier than most other devices’, but we wish the design were more simple. The thumb holder was awkward to grasp, and both of us testers couldn’t seem to align our fingers with the finger nubs.
We also thought the space between the grip and the base to be excessive — a lower height and center of gravity would immensely improve the device’s stability.
Working Section
- Levels of Sharpening:Sharpen (slot 1, 2, 3), Hone (slot 4)
- Abrasive:Tungsten carbide blades, diamond rods, ceramic rods
- Mechanism:Pull through
- Sharpening Angle:20 degree
The Muller has a large working section with one slot for scissors and three for kitchen knives. It’s placed on a rather thick base — in fact, the Muller is among the tallest of all the devices we’ve tested. Unfortunately, this is not an advantage in the world of handheld sharpeners: A high working section only makes it more prone to toppling during operation.
- Levels of Sharpening:Sharpen, Polish
- Abrasive:Ceramic blades
- Mechanism:Pull through
- Sharpening Angle:15 degrees, 10 degrees
The Zwilling sharpener has a long working section, covering two types of edge angle: standard and Asian. We find the alleged grind angles of 15 and 10 degrees to be surprisingly small—standard knives typically come at 18-22 degrees and Asian knives, 13 - 15 degrees. An edge angle of 10 degrees is probably more appropriate for razors than kitchen knives.
Angles aside, we like how the working section is closer to the base than the rest of the device is. This helps lower the center of gravity even only by a little, and improves the overall balance.
Mueller 4-Stage Knife Sharpener’s Base
- Material:ABS plastic
- Feet Type:Anti-slip rubber pads
The Muller has a base running from the heel of its handle to underneath its working section. The base is supported with two flat rubber pads that offer friction and keep it from sliding across the countertop during sharpening.
- Material:Plastic
- Feet Type:EVA pad
The Zwilling sharpener has a solid, flat base, with a high-quality anti-slip pad underneath. But this is yet another area where it suffers from bad design.
The base is long and narrow, which is not ideal for its considerable height. The pad only partially covers the base, leaving its border hanging in the air— the pad basically adds height while further reducing the already modest width. As a result, the device is very prone to rocking.
Mueller 4-Stage Knife Sharpener Review
- Slot Arrangement (10%)7.0/10
- Insertion (20%)9.0/10
- Pulling Through (10%)7.5/10
- Stability on a Clean Surface (40%)8.5/10
- Stability on a Wet and Dirty Surface (20%)8.0/10
- Slot Arrangement (10%)10/10
- Insertion (20%)9.0/10
- Pulling Through (10%)7.5/10
- Stability on a Clean Surface (40%)7.5/10
- Stability on a Wet and Dirty Surface (20%)6.0/10
Slot Arrangement
Unlike many other sharpeners where the diamond rods serve as a “prep” stage, on the Mueller, you start sharpening your knife with the tungsten carbide blades (Slot 2), then move on to the diamond rods (Slot 3) and finish on the ceramic rods (Slot 4). Interestingly, in the Amazon product description, slots 2 and 3 are swapped.
The tungsten carbide blades remove the most material from the knife, so it makes sense that they’re the ‘coarsest’ stage. However, we found that the diamond and ceramic rods may sometimes dullen a keen edge, especially when you use both of them to ‘polish’ it. As a result, we prefer the more common setting of starting with the diamond rods for the straightening effect.
The Zwilling has more sharpening slots than most others, but its layout is straightforward. Half of the working section is for standard blades and the other half Asian, as indicated by the print underneath. The slots progress in the same order for each angle type, with their coarseness level printed on their sides.
A transparent plastic cover can be slid over the area you’re not working on, so it’s rare that you will misplace your knife while sharpening.
Insertion
With a long grip and a wide working section, blade insertion into the sharpening slots was effortless and didn’t require much caution. If you’ve been sharpening with mini-size devices such as the KitchenIQ, where you’re gripping right next to the sharpening slot, you will likely notice the lack of stress when working with the Mueller.
It doesn’t have the widest slot openings, but insertion is still effortless with the Zwilling. Its lowered working section and the rather spacious grip do offer a sense of confidence and safety in this regard.
Pulling Through
The test knife went through the last two sharpening slots with little problem. However, our experience with the coarse slot seemed to be hit-and-miss: Sometimes, the tungsten carbide blades were almost slippery with no friction or pressure felt, which means they weren’t doing their job. Other times, they were tight and ended up removing too much material from the knife.
The problem with abrasive blades is that sometimes they lose grip of the knife edge, letting it glide through untouched. The fact that its blades are made of ceramic instead of tungsten carbide as a typical sharpener’s would be doesn’t exempt the Zwilling from this issue.
The thick frame around the slots, while offering great support, does obstruct the knife tip at the end as the downward force is still in place. It gets nicked from time to time, though this doesn’t affect the knife edge or sharpness.
Stability on a Clean Surface
The Muller keeps its balance well on a dry and clean wooden table or marble countertop. It’s taller than most devices, but thanks to the flat and frictious base, we never had to use excessive force to keep it in place during our multiple tests.
The Zwilling’s heavy weight (a whopping 11 ounces) and solidness couldn’t cancel out the effect of its massive height to stabilize the device. Nor did its narrow base and an even narrower anti-slip pad allow it to fare well in our test. The sharpener kept losing its balance.
Stability on a Wet and Dirty Surface
We had to be a little more cautious on a messy slippery countertop, but as long as you don’t work too fast, balance and stability won’t be an issue.
The oil- and salt-tainted countertop only amplified all the design problems on the Zwilling. We could only keep it in place with excessive force on the grip, and so we highly recommend ensuring your countertop is dry and clean before using this sharpener.