If you have purchased a ceramic knife in the past few years, you may have been persuaded to make that purchase because of a very alluring – yet ultimately false – promise that ceramic knives will not go blunt.
This, unfortunately, is not true and your ceramic knife will eventually begin to become duller and duller. But it’s not all bad news because these ceramic knives can be sharpened. It might be a little trickier than sharpening a steel bladed knife but it definitely is possible.
Ceramic knives are a fairly new trend on the knife scene and they have their pros and cons – the biggest pro being that they do usually stay sharper for longer than steel blades and the con is that they are far more brittle and likely to break.
For this reason, I personally don’t use ceramic knives as I find that in this case, the disadvantage of the low strength of the blade greatly outweighs the advantage of having to sharpen the blade less than a steel knife.
But, each to their own. And you may find that you prefer using ceramic blades. That is, of course, completely up to you. And as there are many people who do like the ceramic bladed knives, I thought it best that we talk about the best way to sharpen ceramic knives when they go blunt.
Why Is Sharpening A Ceramic Knife More Difficult?
The basic answer to this is – because they are so brittle. Their blade weakness means that you need to pay close attention to what you are doing and sharpen the blade in a delicate way so that you avoid snapping the blade in half.
So a word of warning – never press down on the blade with too much force when sharpening a ceramic blade. Doing so will leave you with a knife that has been rendered useless so it’s really important that you keep this in mind at all times when sharpening a ceramic knife.
So how much pressure is too much? Well, that really is for you to use your best judgment with as we all apply force in different ways. But the important thing to remember is that ceramic blades react very differently to steel blades. If you’ve sharpened a steel bladed knife before, you’ll be aware that you can feel the flex and give of the blade as you are sharpening it. We use this as a gauge as to how much pressure we should apply to the blade as we are sharpening it.
Ceramic, which is made from zirconium dioxide, behaves much like glass, meaning that there is no flex in a ceramic blade. So if you apply too much force to the blade as you are sharpening it, you’ll have no warning before and no way of knowing when it is about to shatter into pieces. When it comes to sharpening these blades, less is more. Don’t apply more force than is absolutely necessary.
One final thing that makes ceramic knives more difficult to sharpen than steel blades is that ceramic is not a ductile material so no burr will form on the blade while sharpening. So basically, the sharpness of the edge will be determined by the precision of your movements and the final grit on the edge.
What To Never Do When Sharpening Ceramic Knives
The number one rule – and we’ve discussed it already – is don’t apply too much pressure to the ceramic blade. And the first big mistake that people make is illustrated in the photo below.
Never sharpen your blade while holding only the handle. It might feel like you are barely applying any pressure at all to the knife blade as you run it along the sharpening stone but this incorrect technique will more than likely result in your blade snapping. If you apply pressure in this way, you will be applying far too much force to the middle and rear of the blade and a blades natural reaction will be to flex. But as we know, ceramic blades have no flex so the blade will instead shatter. So, lesson one, never hold your blade like this.
What To Do When Sharpening Ceramic Knives
So, what is the correct way to hold your ceramic knife while sharpening it? By the blade itself. Always hold your ceramic knife by the blade while sharpening. And I suggest – as illustrated in the photo below – that you use both hands on the blade while sharpening. Try to use all your fingers to achieve a consistent and even force across the entire blade. But remember – don’t use too much pressure. Concentrate on running the blade along the stone in a way that will ensure zero flex is generated in the blade. This is the best way to ensure that your knife blade does not shatter into pieces while it is being sharpened.
Whether you run the blade away from you or toward you makes no real difference to the end result so it’s down to personal preference which way you do this. Personally, I prefer to move the blade away from me and only in a one-way motion as that is the way I was taught to do it and I still believe it to be the safest method. But it’s ultimately up to you whether you run the blade forward, back or in both directions.
The thing to really keep in mind while you are sharpening the blade is to make smooth and controlled movements while not exerting too much pressure onto the blade.
Tools To Sharpen Ceramic Knives
While you can use other types of sharpeners to sharpen your blades, I really recommend you stick to the tried and tested diamond stones as they always give a great end result. The extra hardness of the diamond stone means that less force is required to remove material and sharpen the blade and as I’m sure you are now aware, this is very important when it comes to sharpening ceramic knives.
I recommend that you use a 200 grit diamond stone if there are large chips in your blade and then working down through the stones from a 600 grit, to a 1000, then finishing with a 1500.
It is, of course, possible to use waterstones and sandpaper to sharpen ceramic blades but they are not preferable over diamond stones.
And if you are more comfortable using a knife sharpener than just the stones themselves, Spyderco makes a great tool called the Tri-Angle Sharpmaker that can be fitted with a diamond stone add-on. If this sounds like a great option for you, it’s vital that you do get the diamond stone add-on with your sharpener as the standard sharpening stone will most likely break your ceramic blade.
Last Thoughts On Sharpening Ceramic Knives
I’ve said it many times before and I’ll say it again – pressure (lack of it) is key when sharpening ceramic knives. As I stated earlier in the article, I don’t use ceramic knives myself as I find the brittleness of the blades too much of a risk factor to make it a viable option for me.
Ceramic knives, however, will stay sharper for longer, meaning that a lot of people prefer these knives due to their low maintenance and if you are one of those people, don’t let my preferences deter you. Just make sure you follow this guide and sharpen your ceramic blade in the correct way. Do that and you won’t have a problem.