In daily usage, our knives are being strained: we cut, we chop, we mince and even the sharpest blade will lose its sharpness and eventually become dull. Grinding your knife rightly will provide a sharp edge. But which angle should be chosen for the kitchen knives? 12, 14, or 17 degrees – which is the right angle for kitchen knives, and is it possible to change the sharpening angle afterward?
Grinding angle vs. cutting edge angle
Generally, we differentiate between the grinding angle and the cutting angle. The grinding angle is the angle at which the knife will be worked on. Because most of the knives are ground symmetrically, the grinding angle (e.g. 15 degrees) is worked on both sides of the knives’ blade. The sum of both grinding angles results in the cutting edge angle, in our example: 30 degrees.
The grinding angle influences the sharpness and its longevity. The sharper the grinding angle, the higher the cutting ability and/or the sharpness of the knife will be. Indeed due to the fine edge, there will be less resistance while cutting through. Hard carbon steels are being used for fine blades in order for the edge to not break due to the fine grinding. Especially for highly fine cuts, like fileting, knives with smaller grinding angles are more suited. However, due to the fine edge, the knife will get dull quicker.
Larger angles, however, provide less sharpness, respectively a higher cutting resistance, but are more stable and the edge will stay sharp longer.
Most kitchen knife manufacturers recommend a grinding angle between 15 and 20 degrees. Renowned knife manufacturers like Zwilling, Wüsthof, Güde, Kai Shun, or Global usually recommend the 15 degrees grinding angle to sharpen the knives because it perfectly combines the stability of the blade and the sharpness of the edge.
However, chances are that your knife won’t have this exact recommended angle when it comes out of the manufacture.
Bigger manufacturers are already working with a laser-controlled system, in which each knife will have the exact same grinding angle. Nonetheless, this can not be applied to the whole knife industry. A lot of the manufacturers have an automatic process for the individual parts, but the assembly of the knife is still done by hand. As well as the knife’s grind, which is manually done by skilled personnel. It is therefore understandable that there may be variations of 1-3 degrees. The grinding angle ex-works can therefore vary a little bit from the manufacturer’s recommendation.
Knife’s grind
Over the years, many manufacturers have developed special types of grinds. As with the grinding angle, different knife grinds are suitable for certain applications.
The number of knife manufacturers is large and the market is highly competitive. In the kitchen knife sector, some knife manufacturers, therefore, advertise the hollow, ball, skandi, or thin grind in order to stand out from the competition. These types of grinds are usually difficult to resharpen manually at home and must therefore often be given to professionals. This is certainly an important point in the purchase decision, because what good is the most exotic cut if you can not reproduce it yourself?
The V- or wedge grind is the easiest to produce and reproduce due to its flat-cutting bevel. It is the most common grind in the kitchen knife scene.
What grinding angle does my knife have?
The grinding angle ex-works can be found in the manufacturer’s certificate or in the user manual. After the first manual grinding, the angle has probably been changed already. It is almost impossible to numerically determine the specified angle and adhere to it exactly with the mere eye.
The pen-marker method helps to check if it is reproduced correctly: a thin line is drawn on the edge of the knife with the pen marker. Once the color of the marker has disappeared after sharpening the knife, the grind is even and the knife is sharp.
The thickness of the knife’s spine
The thickness or hardness of the knife’s back can also play an important role around the grinding angle. The key factor is how hard the blade’s steel is around the sharpened cutting edge. When the steels are extremely strong, a small grinding angle will only achieve low or no sharp results at all. This can be recognized by the cutting bevel. If it is respectively high, the grinding effect on the enlarged surface is smaller. Furthermore, the grinding process is very long, as a relative amount of material must be removed.
With years of use of a knife, the amount of re-sharpening is accumulated as well. With the related removed material, we increasingly approach the thick back of the knife while re-sharpening the blades. The cutting edge of the knife, which becomes thicker and thicker, is often „thinned out“ by machine, e.g. in the butcher’s sector so that sensible grinding angles can be applied again.
Can I Change the Grinding Angle?
The fact is that in almost all commercially available sharpening methods, knives are resharpened or the angle changed with each application since the angle can not be reproduced by 100%. Therefore, our answer to the question above is ‚yes‘ – but ideally only once, in order to produce a permanently reproducible angle and to remove as little material as possible during regrinding.
It is important to note that not every steel structure is the same and therefore knives often behave differently during the sharpening process. Japanese knives are usually made of harder carbon or carbon steels (usually above 60 Rockwell (=HRC)) that can be ground very fine without breaking. European chef’s knives are usually made of tougher steels (about 55-58 HRC) and can therefore have somewhat more stable angles. The manufacturer’s recommendations should therefore be roughly followed.
However, more important than the 12, 14, or 17 degrees, is the constant reproducibility of the same grinding angle. This is the only way to ensure minimal material removal and the longevity of the edge, which is very important, especially for high-quality knives. One-time sharpening or resharpening of a knife is therefore the rule instead of an exception.
Our Conclusion
The grinding angle for kitchen knives differs depending on the knife model and blade geometry, respectively steel structure, and the areas of application of the knife.
The most common grinding angles, which provide a stable but also sharp result, are between 15 and 20 degrees.
However, more important than the question of the current grinding angle of the knife is the constant reproducibility of a grinding angle. Even knives that deviate from this angle by a few degrees can be resharpened once. In the long run, this is the only way to minimize material removal from the knife to the minimum necessary and to significantly extend the service life of the knife.
We would have never thought that we would find each other professionally, after all, these years. But when our individual skills found the right common project, amazing things came out. A supposedly simple tool that impresses people all over the world. Knife sharpening like a pro – but simpler.
With years of experience in the sharpening industry, we now have built knowledge around all the grinding methods and their inconveniences. We have taken on the topic and developed a solution in which everybody can easily sharpen their damascus knives with the same precision as a professional.
the rotating movement of the grinding surfaces recreate a perfect uniform sharpness for an even blade
the magnetic angle support ensures a constant angle can exactly be repeated to maintain the sharpness
the precise grinding angle limits the abrasion of material, extending the longevity of your knives