Ceramic knives are often sold as the knife which never needs to be sharpened.
Quite simply, this is not true.
What is true is that ceramic knife blades are extremely hard, so they need to be sharpened far less frequently than steel knives would need to be. Ultimately, however; ceramic knives will go blunt with use and they will need to be sharpened if you want to recover that razor-sharp edge which they’re known for.
In fact, I think it’s even more important to keep ceramic knives sharp than it is steel knives. The sharpness of ceramic knives is what makes it unique, unlike steel knives, you don’t need to hone ceramic knives and the sharp edge will remain sharp for a very long time. However, once it does start to go blunt then you risk damaging a ceramic knife due to the brittle nature of the material, having to apply extra pressure whilst cutting increases the risk of twisting a ceramic knife and causing chips and damage in a way which is unlikely to happen with a steel knife.
Sharpening ceramic knives is a little more tricky than sharpening steel knives, and the tools which you can use are more limited. But it is perfectly achievable to sharpen your ceramic knives at home, you just need to know how!
In this article, I’m going to run through everything you need to know about how to sharpen ceramic knives.
To sharpen ceramic knives you need to use a diamond-encrusted sharpening stone. Angle the knife blade at a 15 to 20-degree angle to the stone and then glide the blade along the stone from tip to heel. Repeat the process on each side until sharp.
The benefits of ceramic knives
Ceramic knives are particularly hard. This means that the sharpness of a ceramic knife is retained for much longer than the sharpness of a steel knife.
Additionally, ceramic knives don’t need to be honed using a honing steel. This is a practice that I would recommend you do for your steel knives after at least every three uses, but the edge of a ceramic knife will never fold over, so you don’t need to worry about honing it.
If you’re not sure what honing a knife is, or the difference between honing and sharpening then you can check out an article I wrote on it here. You might not need to hone ceramic knives but it’s still really important to know the difference for keeping your steel knives well maintained.
How sharpening ceramic knives is different from steel knives
Sharpening ceramic knives and sharpening steel knives follows many of the same principles of sharpening. Ultimately you’re aiming to remove a thin layer of the knife edge to reveal a new, sharp layer underneath.
The difference comes due to the difference in hardness between the two materials.
In order to remove a layer of material from a knife, you need to use a material harder than that of the knife, rubbing two materials of the same strength together simply won’t work.
When sharpening steel this generally gives you three popular options, use a ceramic sharpener, a diamond-encrusted sharpener or a whetstone, sometimes known as a water stone. All of these materials can remove layers of steel from the knife.
As ceramic is such a hard material the types of sharpeners we can use are more limited. The best way to sharpen ceramic knives is by using diamond sharpening stones.
You can also use whetstones, as you would for a steel knife, but generally I would recommend using diamond stones for a ceramic knife as they are more specifically for sharpening ceramic blades.
How to sharpen a ceramic knife
There is one key thing to remember when you’re sharpening a ceramic knife. Although the blades are hard they are actually quite brittle. I like to compare them to a piece of marble, extremely hard but will easily crack if you drop it.
This means that you really need to avoid putting excess sideways pressure on the knife blade as it can easily chip the edge of the blade, which would be very frustrating mid-sharpening!
To begin sharpening your ceramic knife I would recommend a diamond sharpening stone. These have a diamond-encrusted surface which is perfect for removing that thin layer of ceramic from your knife to reveal the fresh sharp surface underneath.
There are other tools you can use to sharpen ceramic knives but by far the best option, in my opinion, is the diamond stone. I’ll list the other options later in this article, but for now, I’m going to focus on sharpening with a stone.
Firstly, sharpening stones come in different grits. This is the same terminology used for sandpaper and effectively the lower the grit the more coarse the surface. A lower grit will remove more of the blade, a higher grit will be finer, for polishing the blade and creating a super sharp edge.
If your knife is chipped then you might want to use a 240 grit stone to help remove a large amount of the blade. Then you should use a 1,000 grit stone to create a nice sharp edge.
You can get extremely fine stones such as a 6,000 grit stone. This will help create a very fine and sharp edge but it isn’t essential to use such a fine grit, a 1,000 grit stone will restore your knife to a perfectly satisfactory level.
Lay the stone down on a flat surface. Some stones will come with holders to help keep them in place and not slide around when you’re sharpening. If your stone doesn’t have a holder then you can achieve the same effect by placing the stone on a slightly damp kitchen towel or cloth.
Angle the knife of the blade at a 20 to 15-degree angle to the stone. You don’t need any precise way of measuring this, you’re really just trying to match the angle of the knife blade itself. A handy tip is to start with the knife at a right angle to the stone, that’s 90 degrees. Tilt the blade to half it to 45 degrees, half it once more and you’ll be around 20 degrees.
Use one hand to hold the handle and the fingers on your other hand to support the blade of the knife, pushing down gently on the blade. This will help prevent the blade from snapping or chipping whilst you’re sharpening it, it’s all about evenly distributing any force on the blade.
Start with the tip end of the blade against the stone and glide the blade along and across the stone to sharpen from tip to handle.
Make sure you repeat the same number of strokes on each side. Depending on how blunt your knife is this process can take anywhere from 5 minutes for a knife which just needs a simple sharpening or 20 minutes for a chipped knife which will need to be sharpened with a lower grit first and then finished off on a higher grit.
Tools for sharpening ceramic knives
I would highly recommend using diamond stones for sharpening your ceramic knives as in my opinion they simply produce the best results; however, there are other options for ceramic knife sharpeners.
One thing they all have in common is diamond, you need your sharpener to be harder than the material it’s sharpening and ceramic is such a hard material that really only diamond sharpeners will work for ceramic knives.
One option is the diamond sharpening rod. This is a long rod, around 12 inches with a handle at one end. It’s similar in appearance to a honing steel but has a diamond-encrusted surface to the rod.
Diamond sharpening rods are very effective at removing layers from the knife blade and they will work for both steel and ceramic knives. In my experience, though they are a little too ‘good’ at removing layers of the blade. The diamond sharpening rod can really eat away at your blade if you’re not careful and it’s much more difficult to be precise and deliberate with your actions when using a sharpening rod as opposed to using a stone where you have more control.
Another option, which I think is preferable to a sharpening rod, is using a diamond pull-through sharpener.
Again, it’s important that this is a diamond-encrusted tool, there are loads of pull-through sharpeners available and most will be steel (which is actually useless for sharpening either steel or ceramic knives by the way) or ceramic, so you need to pay attention and make sure to get a diamond one.
They can be electric or manual but the principle is the same. There are two diamond-encrusted surfaces which cross each other at the same angle as the knife. When to draw the knife blade between these two surfaces it is simultaneously sharpened from both sides.
They are super easy to use and I think there’s less chance of damaging your ceramic knife using a pull-through sharpener than a sharpening rod.
Professional knife sharpening services
One majorly overlooked option is to actually outsource your sharpening. This is especially useful if you have a number of knives that you need to be sharpened and it can be rather time-consuming.
Sending your knives out to be professionally sharpened can be really easy, you can usually just send them out in the post. Professional services will be able to sharpen to a very fine level and they’ll be able to restore even the most damaged of knives.
If ceramic knives are well looked after then they don’t need to be sharpened very often at all, so if you’re only looking and sharpening them every five years or so it may be well worth having them sharpened professionally rather than investing in the sharpening stones you would need to do it yourself.
Of course, you would be able to send all your knives, ceramic and steel alike, at the same time and you’ll have a whole set of sharp knives in no time.
Tips for ceramic knife maintenance
You will need to sharpen your ceramic knife far less frequently if you can avoid damaging the blade. Unfortunately, it is very easy to end up with a knife dotted with little chips right along the blade edge. Eventually, your knife starts to become more of a saw than a super sharp blade.
But there are some pretty simple measures you can take to drastically reduce the chance of your ceramic knives getting damaged. It’s all about reducing the number of sudden impacts on the knife.
Store safely
You need to look after your knife even when you’re not using it. It is all too easy to throw your knives into one communal knife drawer. The issue with this is that as the drawer is opened and shut the knives will jingle around a hit against each other. This is a bad environment for a ceramic knife and the likelihood of the blade chipping is high.
It’s much better to store your ceramic knives in their own container where they can be safe from movement.
Alternatively, you can use a blade sheath for the knife, these can be made from plastic and come with your knife set, or you can fix up a makeshift version by wrapping a cloth around the blade and securing it with an elastic band.
Avoid hard food
When using the knife you need to avoid using it on food containing and hard sections. The obvious one is bones, so I would generally not recommend using a ceramic knife to prepare and meat with bones in it.
But it’s not just bones, any fruit with a hard stone, an avocado, for example, poses a threat to your knife. So as much as you can, only use your ceramic knife to slice through soft food. Keep to that rule and your knife will last a very long time before it needs to be sharpened.
Summary
Ceramic knives can be a great tool and you can easily sharpen them yourself at home using a diamond sharpening stone. But if you want them to last longer between sharpening then you need to be careful with them and ensure you maintain them properly.
There is also the option to send your ceramic knives to a professional knife sharpener who will be able to restore even the bluntest knife to a razor-sharp edge.
