Water Sharpeners Have Their Place in Sharpening Too

A sharpener that is a whetstone made simple!

Is that what a water sharpener is? While at first glance it might appear so, does it sharpen a blade to the same shape that a whetstone does? This article delves into that, as well as precisely what water sharpeners are useful for. They very much have a place in the kitchen knife industry!

What is a water sharpener?

Every time you use a knife, it's going to get more dull. This is an inevitable part of knife usage.

Because of this occurence, we sharpen our knives. Normally, one would use a whetstone to sharpen a Japanese knife, but this is time-consuming and difficult to do.

For that reason, sometimes we use water sharpeners instead for simple sharpening - they are quick and convenient, plus easy to use.

The benefits of a water sharpener

The biggest advantage of water sharpeners is their simplicity. In short, they're easy to use.

Sharpening with a whetstone takes time, effort, and practice. Even in store we are always learning more sharpening strategies, and teaching new staff how to do it. Make no mistake, sharpening with a whetstone is not simple - however it is also very rewarding.

A water sharpener removes this barrier, however, as they aren't time consuming plus need no real practice. A sharpening using one of these should only take a couple of minutes.

The downsides of a water sharpener

The biggest disadvantage is that, compared to a whetstone, a water sharpener just can't produce the same sharp cutting edge at the end. This is because of the way sharpening works in general. For context, a key part of sharpness is to make a thin blade with a finely honed cutting edge.

To do this, we use different whetstones over a series of passes in order to finely dial in the sharpness we are looking for. For example, in-store we use five whetstones as a minimum when sharpening, and often more. A water sharpener alone normally only has three stones in it.

So while these tools are incredibly convenient, they do sacrifice sharpness as an end result. While this is a disadvantage, this doesn't make these sharpeners bad per se - merely have a different purpose which we'll get into later.

How to use a water sharpener

Water sharpeners are amazingly easy to use, which makes them brilliant for just starting out. Follow along with the steps below:


  1. Place a wet towel on a stable table or surface. This is to keep the sharpener steady.
  2. Add water to the sharpener body itself.
  3. Place the sharpener on the wet towel and grip the handle of it firmly.
  4. Place the cutting edge of your knife between the roller gap of the roughest stone on there and move it back and forth approximately ten times with a fairly light level of force.
  5. If your water sharpener has different levels of whetstone in it (the ones we sell in-store have three), use them in order of roughest to finest by repeating steps 2 to 4.


That's all you need to do! Again, water sharpeners are incredibly easy to use and a brilliant way to just do a simple sharpening on your knives if you don't have time to use your whetstones.

Differences between water sharpeners and whetstones

Since water sharpeners are so easy and quick to use, you may think there's no need to go through the time-consuming and difficult method of sharpening with a whetstone. However, the fact is that, again, you won't get the same sharpness levels back on your knife compared to doing it with a whetstone. It's a whole different level of sharpening, to the point where the definition of "sharpening" between the two devices is different.

Like we said earlier, as you use a knife more and more it will become more dull and eventually stop cutting. What we mean by "stop cutting" is the edge of the blade has worn out and started curling, so the cutting edge just slips off instead of cutting anything you apply it to. If you place a blunted knife against your fingernail for example, you'll notice it just slides. We sharpen to get that cutting edge back and remove those curls.

When sharpening with a whetstone, the blade is sharpened in order from rough to finishing, and the blade can really be honed and dialed in. This to us is the essence of sharpening. In turn, a water sharpener roughens the smoothed edge of the blade back into jagged edges, so it catches on food again. This may make you feel like the sharpness has returned to the blade, but it's completely different compared to using a whetstone sharpened blade. In essence, the condition of the cutting edge is completely different.

Of course, if you put a knife that has been sharpened with a whetstone next to one done with a water sharpener, they're both going to be able to cut food. However, there will be two key differences - one in the cutting edge itself, and one in the blade's durability. Let's dive into both a little.

The difference in cutting edge

The water sharpener roughens the rounded edge of the blade so it gets caught in food once again and thus cuts. It does this by creating large serrations on the blade. These larger serrations will cause cuts to food to be quite rough. Another term for this would be that the knife would now have a poor kireaji - the feeling behind cutting would not be good, and there won't be any kind of amakire (sweet cut). A whetstone shapened knife will cut through significantly more seamlessly, like you're cutting through thin air if done correctly.

The difference in blade durability

A blade that has large serrations means that there's fewer serrations on that blade too. As a water sharpener causes large serrations and thus less serrations, this also means that the durability of the sharpness achieved is greatly hampered. In short, you need to sharpen significantly more often as it will wear our way quicker than if the knife has been whetstone sharpened. This will be especially apparently when cutting on harder things, like certain root vegetables.

Here's some examples below of cutting edges using a water sharpener and a whetstone. Below that is also a cross-comparison with left to right being water sharpener, medium whetstone and finishing whetstone. You'll notice the differences are very apparent.

This is a close-up of a blade's cutting edge, sharpened with a water sharpener.

Since only the cutting edge itself has been sharpened, notice there is a two-stepped blade on the edge with different angles.

Also take a look at the polishing scratches - they're very deep, with larger and even slightly visible serrations. Water sharpeners tend to do this beause of the pull method you need to do when sharpning using them.

This edge instead has been sharpened by hand on a medium grit whetstone.

Unlike a water sharpener, you can sharpen to a very thin state which removes any two-stepped blade. Additionally, the polishing scratches are thinner, so the edge of the blade is less rough - meaning it will cut through food better. The end result is a thinner blade, which performs better and lasts longer.

Finally we have the edge sharpened with a finishing whetstone.

The scratches are even more shallow on this blade, meaning cutting performance and kireaji will once again be improved.

A water sharpener is quick, but a whetstone produces a better cutting ability

Situations where a water sharpener is useful

There are situations where a water sharpener is useful, so don't rule them out completely. See a few examples below:


  • When being used by those who are not good at sharpening with a whetstone
  • When the blade dulls while you're busy cutting
  • Those who are time poor


While water sharpeners and sharpening stones give very different finishes, we also believe they have very different roles in the world of sharpening.

Of course, it would be nice if we could always use whetstone sharpened blades, but it does take time and effort to do - something we don't always have, especially if the knife has blunted during a work session.

But, in contrast, if you only ever use a water sharpener, your knife will eventually lose all its cutting strength.

The advantages and disadvantages of both methods of sharpening though complement each other quite well.

If you have the time to properly sharpen your blade, a whetstone sharpening is perfect, but if you're simply too busy or time poor or your knife has failed at the workplace, a water sharpener is a perfect tool to use for such situations to keep your knife sharp just a little bit longer until your next whetstone sharpening.

Using them in tandem (along with other tools) helps you create a complete sharpening solution, so that your knives stay sharp and cut well, all while respecting your time so you're not spending all your time maintaining your knives.

We don't sell water sharpeners on our website, but contact us or come in-store and we can help you out!