Ceramic knife sharpening isn’t quite as simple as you may think
Ceramic knives have become more popular over the last few years and as a result owners of ceramic knives are asking about the best way to go about ceramic knife sharpening.
The first observation to make is that many knife sharpeners labelled as “ceramic knife sharpeners” are often sharpeners intended for steel knives, but with ceramic sharpening surfaces. However before we get into looking at ceramic knife sharpening we wanted to look at what exactly ceramic knives are.
One of the determining factors which affect how well a knife holds its sharpness, or its edge, is the hardness of the material that is used to make the knife blade. The harder the material used to make the knife blade the better it will hold its edge.
There is a scale of hardness called the Mohs scale, on which the hardness of materials are rated. Diamond, for example, scores a maximum of 10 on the Mohs scale. Stainless steel, which is the material used to make many kitchen knives, ranks around 5.5 on the Mohs scale, and hardened steel sits around 7.5. A good ceramic knife should score over 8, indicating that it’s extremely hard.
Commonly quality ceramic knives are made from zirconium oxide, in a quite complex manufacturing process.
Ceramic knives are known for their sharpness, or more specifically for the length of time that they will maintain their edge. In fact Kyocera, who are one of the major manufacturers of ceramic knives, maintain that they can last up to 10 or even 15 times longer than steel knives. A good ceramic knife should need sharpening only rarely.
(See below for a fascinating video on how Kyocera make their high quality ceramic knives).
Ceramic knives also have other advantages over stainless steel knives, as well as disadvantages. They are lightweight and as previously mentioned hold their edge well.
And they are resistant to rusting or other forms of deterioration.
They are non-magnetic and do not conduct electricity, and according to the experts do not impart any effect on the flavour of any foods they are used on, because they are chemically inert. Steel knives can affect food they you are used on. Try cutting lettuce with the steel knife and take a look the next day.
However they can also be more brittle, and are really only suitable for slicing soft foods. They can break and should not be used on anything hard like bones. Don’t drop one, don’t store it in your knives drawer with other knives and don’t pry, chop or do anything else other than slice with your knife.
Ceramic knife sharpening. How to and what with
So, on to ceramic knife sharpening. Despite the fact that they are supposed to maintain an edge for a long time they will still get dull eventually. And not all ceramic knife sharpeners are what the name would suggest. For instance do a search on Amazon for ceramic knife sharpener and you’ll see ceramic rods. These aren’t for sharpening ceramic knives, the “ceramic” refers to the material that the rod is made from.
If you’re sharpening a ceramic knife then you need to be using a sharpener that is made from a material that is harder than the ceramic in the knife. That’s because, to sharpen the knife, the sharpener needs to remove material from the blade, and if it’s softer than the blade it will not do so.
Of course there are always ceramic knife sharpening services available, many are available by mail, so you don’t need to find one near you. And as ceramic knife sharpening isn’t all that easy, and needs to be done only rarely, selecting a good sharpening service may well be a fine solution.
And some of the best ceramic knife manufacturers will sharpen your knife for you if you return it, which may be a good choice. Check with your manufacturer.
But for many people sharpening your knife yourself is always an attraction. No need to send it away so it’s unavailable when you need it, and even just for the satisfaction of knowing you can do it yourself. As well of course, once you have the sharpening tools, you need spend no more on sharpening your ceramic knife.
There are ceramic knife sharpeners available. Kyocera make a ceramic knife sharpener, the Kyocera Electric Diamond Knife Sharpener for Ceramic Knives that has very good reviews on Amazon, and for someone who is looking to sharpen their own knife that should be a good choice. It has diamond grinding stones (with spares available if needed).
This ceramic knife sharpener is electric (battery), and has a blade guide to hold the knife at the right angle, always a problem with manual sharpening. It can be used left or right handed. And it should do a superb job, Kyocera make very high quality products.
For people more interested in a superb result a diamond Whetstone such as the DMT W6EFC Three 6-Inch Diamond Whetstone which will produce a great result, diamond being harder than ceramic. Of course this requires practice and skill to learn how to use the stone and hold the knife at the right angle. This is a set of 3 high quality diamond wet stones.
Here’s how you use DMT diamond stones with a ceramic knife.
And here’s a brilliant video on how Kyocera make their ceramic knives. Well worth a few minutes to watch.
For a more complex discussion about the differences between steel kitchen knives and ceramic kitchen knives see here http://housewares.about.com/od/cutleryknives/a/Ceramic-Vs-Steel-Kitchen-Knives.htm