The best and cheapest abrasive for kitchen knives
Since the beginning of metal knives, whetstones have been the non plus ultra of knife sharpening.
Other than Otto the Great, Hägar the Terrible, or Musashi Miyamoto , In earlier times edged weapons could only be sharpened with stone. And they were definitely really hot.
There are a lot of good, natural stones on the market
Some names are well known, almost famous, like the Arkansas, the Belgian Brocken, or the Japanese Wasserstein.
All natural stones are sedimentary rocks, or limestone rocks with embedded hard crystals. The hardness of the crystals determines the quality and granulation of the stones.
There are deposits of quartzite, mica, corundum, silicate, carbide and more.
Sedimentary rocks are known because in their natural occurrence they consist of coarser sediment on one side and finer sediment on the other
These sediments can vary greatly in color. You can therefore recognize the Belgian chunk by its yellowish and coarser dark layer.
The natural whetstones differ in density, homogeneity and embedded crystals.
Depending on the quality, you can buy bad stones from Asia for a few euros.
Good stones are dense, with a high proportion of crystalline elements. You can buy such a stone from 30 euros.
Lace stones are not only expensive because of their quality. They have been mined in quarries for centuries. This leads to a shortage of good large pieces and thus to an increase in price.
synthetic sharpening stones are very cheap, with these there is a hard crystalline substance brought into shape by means of a plastic bond.
The abrasive media are mostly synthetic corundum. These can be made using the smelting process. The qualities range from dark normal corundum to high-quality special corundum.
The types of corundum differ in colour. Depending on whether chromium or zirconium is specifically inserted into the crystal lattice. The precious corundum is tougher and less splintering. Grinding blocks made from this abrasive are of higher quality and more expensive.
If you choose a cheap corundum, the bond remains flexible. Use the blade to gently scrape grooves into the surface. The hard corundum comes off the bond easily and the sharpening process is always a bit sandy.
Top quality stones have an even distribution of grains and support grains in high Quality. In addition, there is a firm bond with one another.
Many of the natural stones are wetted with water to sharpen the blades. This cools the process and removes the metal abrasion. These stones can be sharpened spontaneously without any preparation time.
The so-called water stones are not only found in Japan
Some stones work better when completely saturated with water. Coarser, more porous stones have already become soaked after 10 to 15 minutes.
For very fine, dense stones, it is advisable to soak them in a bowl of water overnight.
More porous rocks wear out faster, but drain the spent top layer of grain more easily. This can be an advantage.
The dense stones often have a fine grain size in the thousands. Again, there is very little wear. This makes the high acquisition costs acceptable.
Grinding kitchen knives with oil stones
Sharpening with oil, a very old tradition of knife care.
When our knives were mostly made of carbon steel and rusted, the oil stone was still very common. The fine layer of oil temporarily prevented corrosion.
Natural oil stones are very dense and wear-free stones. The best known are the American Arkansas and the Ouashita stone.
The most desirable are the white, slightly porous, and slightly softer varieties. But their occurrences are almost exhausted
The handling of these stones is not easy.
To freshen them up, you need to clean the stones with soap and hot water.
Then you can finish them with a silicon carbide stone. After that they are smooth again, the surface is rougher and more porous. Then start sanding again with a little oil. The result is an exact, almost polished sharpness of the blade.
Suitable oils are petroleum, lamp oil, ballistol or watchmaker oil.
Sharpening knives requires a sure hand and the right twist.
A good sharp knife sharpening requires proper preparation of the abrasive
All whetstones should be prepared for sharpening.
If they are jagged or a hollow has formed in the stone, the stone must be dressed or straightened. This is possible with a flat, harder and coarser stone.
The smoothed stone is best placed on a folded damp kitchen towel.
This prevents slipping while also absorbing excess water during the sharpening process.
Grinding angles are crucial for sharpness and edge retention.
Regardless of how you pull your knife over the water or oil-wetted stone, it is crucial to maintain the sharpening angle. For orientation, simply cut out a piece of cardboard with 15 degrees.
This triangle corresponds to the angle from the sharpness to the back of the knife. Memorize this and always try to keep the blade at this pitch. It helps to use your fingers as a distance sensor.
To sharpen, the blade is pulled across the stone in an arc-like motion. The important thing is that the movement must reach evenly from the tip to the end of the knife.
Pressure and angle must be constant. Take your time, repeat the movement several times until one side is sharp.
Then start on the other side, trying to do as many passes, just as consistently, as on the first side. Don’t forget to add water or oil.
You can start this process with a coarse stone and continue with other, finer stones.
In everyday kitchen use, however, a medium-grained stone is perfectly sufficient.
In our third part about knife sharpening, we deal with sharpening methods, the sharpening steel and other alternatives to the classic stone