Can you sharpen a knife with stones?

Knife Sharpener: You have to know that

Check the blade material

However, before you get a sharpening steel, a whetstone or an electric knife sharpener, you should first take a closer look at your knives. Because not every knife sharpener is suitable for every knife. European knives made of stainless steel or chrome-molybdenum-vanadium steel that are sharpened on both sides can be sharpened with almost any knife sharpener, provided they have a smooth edge. Japanese knives with one-sided sharpening, on the other hand, should not be sharpened with a manual or electric knife sharpener or a steel sharpener. You can also safely leave the resharpening of ceramic knives to a professional, as the extremely shock-sensitive blade can be damaged very quickly if it is improperly resharpened.

Test the sharpness of the blade

How dull a knife actually is can easily be checked with the tomato test. The blade should be placed on the tomato without pressure. If the blade goes easily through the skin, the knife is still sharp. If the blade is only slightly blunt, a fine sanding or a short trigger with a sharpening steel is sufficient. More heavily damaged blades that cut through the tomato skin with difficulty or only with strong pressure, on the other hand, should be processed in several work steps so that they again impress with perfect cutting results.

Sharpening steel, whetstone or electric knife sharpener?

Basically, the question does not actually arise, because in order to ensure all-round carefree maintenance of your knives, it is best to have at least one variant of each in your closet. Unless, of course, you actually only use a single knife for all of your cutting jobs. If not, here is a little guide on what you need for what and how sharpening works with the individual helpers.

The grindstone

Whetstone from the Shun series by KAI

Here, too, there is no one whetstone. Depending on the grain size, each whetstone has a different area of ​​responsibility. Depending on your preference, you can even choose whetstones made of different materials. In general, however, whetstones offer a more deeply effective sharpening result than, for example, the sharpening steel. This means that a good whetstone is essential if you want to restore a severely blunted blade to its old sharpness.

The grit

Grinding stones are suitable for pre-grinding, main grinding and fine grinding. So that the stones don't take up too much space in the kitchen drawer, manufacturers such as KAI offer combination stones that have two differently grained sides. For the preliminary grinding you need a coarse grindstone, i.e. with a low grit (e.g. between 120 and 400 for Japanese grindstones). The blade is ground on the stone until a continuous ridge bulges on the cutting edge. To create such a burr on both sides, work the blade on both sides.

During the main cut, deeper grooves are then removed. For example, Japanese sharpening stones with a grain size of 1,000 or European hard-bound stones with a grain size of 280 are suitable. If the blade of your knife is only slightly blunt, you can simply skip the pre-sharpening and start straight away with the main sharpening. If your knife is primarily used to cut meat or tomatoes, you should also omit the fine-tuning, as this ensures a less "aggressive" sharpness. Japanese whetstones with a grain size of 6,000 are suitable for fine-tuning. It can be even finer: With an 8,000-10,000 grit, your knives even get a shiny polish. Since this is irrelevant for the cutting result, such a polish is more of a gimmick than a necessity. In general: the finer the stone, the less you will feel the burr later.


The material

Similar to knives, there are also whetstones in different material variants. The material processing mostly results from the origin of the stones. In modern Japanese waterstones, the abrasive granulate is usually bound in a ceramic matrix. As a result, they are very hard and only wear out slowly. They are of course ideal for sharpening Japanese knives that are made of hard Damascus steel.

European oil and water stones wear out even more slowly than Japanese ones under the same stress. What makes them special: they can be used not only with water, but also with oil. The sanding is smoother as a result. However, once you have soaked the stone with oil, you can no longer use it with water.

It can actually be even harder: The surface of diamond stones consists of fine diamond dust. There is a metal plate underneath. Diamond stones ensure a high level of abrasion on the blade and are therefore more suitable for coarser grinding work. When sharpening, however, you should be careful not to press the blade too hard onto the stone, as this can damage the coating.

Sharpening with a whetstone: this is how it works

Before sharpening, the whetstone must be immersed in water for at least 10 minutes - or alternatively in oil. This creates a grinding sludge that ensures an optimal grinding process. That is why it is important to ensure that the stone always has enough moisture during grinding.

Once you have chosen the right stone, it is extremely important to maintain the correct angle (15 - 20 °) when grinding. If you don't feel completely safe, you can also use a sharpening aid that is simply slipped over the knife and always ensures the desired angle. Now it is still important to find the right rhythm. Start with the tip of the blade and then pull the blade over the entire stone. The rule of thumb is: "push" forwards and "relax" backwards. To get an even result, you should sharpen both sides of the blade with the same number of strokes - preferably at least twice on each side. With knives sharpened on one side, however, you should sharpen the blade at least 80% on the sharpened side and 20% on the unsharpened one.

The sharpening steel

Sharpen knives with a sharpening steel

When it comes to sharpening steels, there are actually two variants, the simple sharpening steel and the sharpening rod. The sharpening steel or sharpening rod is not used to remove blade material, but primarily to maintain the sharpness. In particular, blades made of stainless steel or chrome-molybdenum-vanadium steel wear out faster without dulling completely. By sharpening your knife briefly with the sharpening stick before or after each use, you can keep the sharpness longer without having to go through the entire sharpening procedure. The main thing here is to straighten the ridge again. A sharpening rod is a sharpening rod with which a new sharpness can be achieved with already blunted knives. There are two versions: Ceramic sharpening sticks are particularly gentle and gentle on the blades, so that they are even suitable for sharpening Japanese blades. Diamond-coated sharpening rods ensure a particularly fine degree of resharpening, but wear out a little faster than ceramic rods.

Sharpening with the sharpening steel made easy

So that you can easily sharpen large chef's knives with a sharpening steel, it should be longer than shorter. For the first attempt, you can simply place the steel vertically on the work surface or a table (handle above) and pull the blade downwards to the right and left along the rod. This guarantees the correct grinding angle.

Electric / manual knife sharpeners

Anyone who does not trust himself to sharpen with a stone or a stick can also use an electric or manual knife sharpener. They are usually even provided with several sharpening devices so that you can use them to sharpen your knives coarsely and finely. The grinding angle is also already specified, so you can't go wrong with that either. Such knife sharpeners are only suitable for blades that are ground on both sides, a few even for knives with a serrated edge.

Our additional tips for long-lasting spiciness:

A sharpening stick isn't the only way to keep your knives sharp for a long time. For one, you should really only use each knife for its intended purpose. On the other hand, cutting surfaces that are too hard, such as glass, porcelain or baking trays, are harmful to the blade - especially for smooth cutting edges. And when you push clippings from the cutting board into the pot, you should only use the back of the blade. If you only follow these tips, you can look forward to long-lasting sharp knife blades.