How do you sharpen a dull knife?

Therefore, you should keep the knife sharp

There are many good reasons to keep a knife sharp and well-sharpened. Most of us use knives daily, mainly in the kitchen but also in slicing bread as well as outdoor activities, hunting and fishing, and more.

There are many strong arguments for always keeping knives sharp:

1. Safety: A sharp knife is a safe knife. If the knife is dull, you need to use more force to cut. If it then slips, the knife can cause great damage.
2. User satisfaction: It is frustrating to use a dull knife. The knife does not behave as it should. It can slip and you have to cut it several times. When cooking, the slices are not as thin as you thought and it is difficult to chop vegetables and spices.
3. Efficiency: Those who use knives at work, for example, chefs, become less efficient if the knives are dull. Increased efficiency in the workplace means increased profitability for the company.
4. Health: A very dull or damaged knife can easily become a haven for harmful bacteria. By sharpening the knife regularly, it will be easier to keep it clean.

This is how grinding works

Sharpening vs. Grinding

First of all, we should distinguish between sharpening and grinding. Every time the knife is used, small particles are carried from the edge to the side. The more the knife is used, the duller it becomes. When sharpening the knife, it means cleaning the edge of these small particles just before use. With the help of a whetstone or a whetstone stick, the small particles are scraped off. They say that you sharpen the knife. The knife becomes sharp again, but it is not a question of sharpening the knife.

When you sharpen a knife, you restore the wedge shape of the edge. A well-sharpened knife retains its sharpness longer. The difference between a sharpened and a well-sharpened knife is how long the sharpness lasts. A knife that has been sharpened can be very sharp but quickly dulls again. On the other hand, a well-sharpened knife stays sharp longer.

Sharpening the knife with a sharpening stick is something you can happily do every time the knife is to be used. You can also sharpen the knife daily at home with a whetstone, although few do it that often. At regular intervals, it can be good to return the knives for sharpening to a professional knife sharpener.

Maintenance grinding vs basic grinding

There is an important difference between maintenance grinding and basic grinding. Maintenance grinding is the type of grinding that anyone can do at home. With the help of a whetstone or roller grinder, you restore the wedge shape of the edge. The knife becomes sharp again.

Over time, the edge still becomes so worn that a basic sharpening is needed. Then a new foundation edge is built up. It’s something that only professional sanders can do well. To help them, they have professional grinding equipment.

Different ways to sharpen and sharpen the knife

There are many ways to keep a knife sharp. Which method and which tools should be used depends on how worn the edge is, how often the knife is used, and what it is used for. The main methods of keeping the knife sharp are:

• Sharpener: Used daily, often right before the knife is to be used. Sharpens the edge.
• Whetstone: Used in the home to sharpen the edge. Available in different coarse grains.
• Roller grind: A simpler method than the whetstone. Works well if the roller grind has the same angle as the knife edge.
• Professional sharpener: A person who has trained as a sharpener and who uses professional sharpening equipment to restore the knife to new condition.

The edge – sharpens the knife for everyday use

In everyday life, a sharpener or a sharpening rod is used to sharpen the knife. When sharpening the knife, it is not a matter of sharpening. The edge is cleaned of small deviations that occur when the knife is used. With the help of the edge, the knife is prepared just before use.

Three types of brows

There are essentially three types of brows. The type of whetstone you should choose depends on the type of knife you have and the strength you want on the whetstone.

• Steel edge: Also called sharpening steel and is rod-shaped. A very common sharpener in, among other things, kitchens. Fits well with European knives. The steel edge is too soft to be used on Japanese knives.
• Ceramic edge: Harder than steel edge and can therefore also be used on Japanese knives. Also suitable for European knives. Made from synthetic sapphires. The ceramic sharpener is available both as a flat sharpener and as a rod.
• Diamond edge: A very strong edge that can be used on both European and Japanese knives. Consists of industrial diamonds. Keep in mind that the edge will be a little rougher than when you use a ceramic sharpener! Most diamond brows are flat.

Read another article about Popular types of steel for knife blades

How to sharpen the knife with a sharpener

It is easy to sharpen the knife with a sharpener. It’s easiest if you think you’re going to try to cut a thin slice out of the brow.

With a steel edge/sharpening steel, you do this:

1. Place the knife against the brow. The angle should be the same as that knife is sharpened. If in doubt, it is better to keep a smaller angle than too large an angle.
2. Pull the knife towards you along the brow, alternately on every other side. Repeat ten times per side. It is also good to hold the sharpening steel against a cutting board and pull the knife down towards the cutting board.
3. Test if the knife is sharp by gently running it over the nail. It should stick to the nail.

The method is similar to a flat sharpener:

1. Hold the brow in your hand or steady it with your hand on the table.
2. Move the knife over the sharpener at the same angle as the edge is sharpened. Make sure that the entire edge of the knife, from root to tip, passes through the sharpener.
3. Alternate between both sides of the knife about ten times per side. The pressure against the brow can be quite hard.
4. Test if the knife is sharp enough.

Tip! If you find it difficult to see how the edge touches the knife, you can color the edge with an alcohol pen. Then you immediately see what effect the brow has on the edge.

Sharpen the knife with a whetstone

If the edge does not become quite sharp even though the knife has been sharpened with a sharpener or if it becomes dull quickly, it needs to be sharpened. Grindstones of different coarseness/grit sizes can be used in the home. It can be good to start with the following grain sizes:

• <700 grains/cm2: Grinding stone with the coarsest grain. First, you sharpen the knife with this whetstone. Removes small nicks from the edge and can be used to re-profile the blade.
• 800 – 2000 grains/cm2: The average grain. Makes the second step in the grinding process. This whetstone can also work for everyday grinding. Gives a perfectly good result, even if the edge can look a little foggy.
• 3000 grains/cm2: Fine-grained grindstone. Has a polishing effect on the edge. Used to make the edge completely shiny.

How to sharpen the knife with a whetstone

When you grind with a whetstone, you always start with the stone with the highest grain size and finish with the finest-grained stone. It is possible to use a single stone, but for best results, two or three different grinding stones should be used. How to use:

1. Soak the whetstone until it starts to bubble. A fine-grained stone must not be soaked for too long.
2. Hold the knife with a firm grip on the whetstone. The angle of the harrow to the stone should be 10 to 15 degrees. At the same time, the entire knife must be pulled at a 45-degree angle about the length of the stone.
3. Press with your thumb against the heel of the knife (right hand if you are right-handed). With two fingers from the other hand, apply firm pressure over the edge of the knife against the stone.
4. Sharpen one side of the knife. Remove the raw edge that forms on the other side. A rough edge should form along the entire blade if the grinding is done correctly.
5. Add water with a cloth from time to time so that the stone does not dry out.
6. Leave grains released by the stone as they are used as abrasive together with the steel scraps. Just make sure that no particles follow to the next stone.

Sharpen the knife with a roller grinder

The easiest way to sharpen a knife is by using a roller sharpener. With one, you just run the knife back and forth through the roller sander a few times until it is sharpened. The big advantage of a roller sander is that it is incredibly easy to use. A roller sharpener takes up little space and sharpens the knife in just a few seconds.

However, there are a couple of disadvantages with roller grinders compared to whetstones. First of all, not all knives can be sharpened with a roller sharpener. If the angle of the edge differs from the angle of the roller sander, the sanding will fail. You can easily test whether the roller sharpener works on your knife by coloring the edge with an alcohol pen. If the paint is removed from the roller sander, it fits. Another disadvantage is that over time the blade profile will lose luster unevenly if only roller sanders are used. Then the knife must be reprofiled.

Take the knife to a professional sharpener

A professional sharpener has undergone special training to sharpen knives. In Japan where knife sharpening is a matter of honor. Sharpeners train there for up to ten years before they are considered fully trained. Professional knife sharpeners have advanced sharpening equipment to help them. Many chefs submit their knives to professional sharpeners at regular intervals to restore the knives to their original shape.