How to Sharpen Knives: Tips for Lasting Sharpness

A blunt knife is more than just an annoyance. It is inefficient and dangerous. Whether you are cutting vegetables in the kitchen, working with wood in the workshop or trimming the hedge in the garden, a sharp blade delivers clean results and requires less effort. This improves both the quality of your work and your safety. Learn the basics here to sharpen your knives and tools yourself and keep them ready for use for years to come.

Why is a sharp knife so important?

The importance of a sharp blade is often underestimated. It is the foundation of precision and safety for countless tasks around the home, workshop and garden. A sharp tool is a good tool.

Greater safety at work

A blunt knife can easily slip off hard surfaces instead of cutting into them. You have to apply more pressure, which reduces your control over the blade. This can lead to uncontrolled movements and a significantly higher risk of injury. A sharp blade, on the other hand, immediately grips the material. It makes a precise cut with minimal effort.

A sharp knife is a safe knife. A blunt knife is just waiting to slip and injure you.

Efficiency and clean results

With a sharp blade, you work faster and get less tired. In the kitchen, a sharp chef's knife glides effortlessly through tomatoes without crushing them. In the garden, a sharpened pair of pruning shears makes a smooth, clean cut that causes less damage to the plant and promotes faster healing. Blunt garden tools, on the other hand, fray and crush plant tissue, making it more susceptible to disease.

Longer tool life

Regular maintenance, including sharpening, significantly extends the life of your tools. Instead of replacing a blunt knife, invest a few minutes in maintenance and keep it working properly for years. This not only saves money but also helps protect the environment.

What tools can you use to sharpen knives?

The market offers a wide range of sharpening tools. Choosing the right instrument depends on the type of blade, your experience and the result you want to achieve. The methods are generally divided into manual and electric options.

Manual sharpening methods

Manual methods give you complete control over the process. They require some practice, but when used correctly they produce excellent results.

Honing steel: A honing steel does not sharpen in the strict sense; it realigns the blade's fine burr, a process known as honing or stropping. Regular use helps maintain the basic sharpness for longer, so you need to carry out a full sharpening less often.

Whetstones: The classic choice for precise results. Whetstones are available in different grits. A coarse grit (e.g. under 1000) is used to remove material and shape a new edge on very blunt blades. Medium grits (1000 to 3000) create a usable edge. Fine grits (over 3000) polish the edge to produce a razor-sharp finish.

Pull-through sharpeners: These devices are easy to use and well suited to beginners. The blade is pulled through preset grinding wheels or ceramic rods. The disadvantages are the fixed angle and often substantial material removal. They are well suited to everyday spatulas and knives.

Electric sharpening tools

Electric devices take much of the work out of sharpening and deliver good results quickly. They are ideal when you need to sharpen many knives or larger tools.

Electric knife sharpeners: Compact kitchen devices with rotating grinding wheels. They are quick and easy to use, but often give you little control over the sharpening angle.

Wet grinders: These professional machines are the best choice for high-quality tools. A slowly rotating grinding wheel runs through a water bath. The water continuously cools the blade, prevents overheating and binds the grinding dust. Machines such as the Bernardo Tabletop Sharpener

Bernardo Tabletop Sharpener DS 200 S / 230V

View product

Bernardo Tabletop Sharpener DS 300 S / 400V

View product

Bernardo Tabletop Sharpener DSA 150 / 230V

View product

How do you find the right sharpening angle?

The sharpening angle is crucial for your blade's sharpness and edge retention. A smaller angle creates a very sharp but also more delicate edge. A larger angle produces a more robust but less refined edge. The angle is always measured per side, so a 20-degree angle means 20 degrees on each side, resulting in an included edge angle of 40 degrees.

• 15-17 degrees: For filleting knives, razors and Japanese kitchen knives. Maximum sharpness for very fine cuts.
• 18-22 degrees: The standard for most European kitchen knives. A good compromise between sharpness and stability.
• 25-30 degrees: Suitable for pocket knives, hunting knives and robust hand tools that need to withstand more wear.
• Over 30 degrees: For axes, hatchets and machetes. Durability is clearly the priority here.

Guide: How to sharpen a knife with a whetstone

Sharpening on a whetstone is the most traditional and versatile method. With a little practice, you can achieve the best results.

Step 1: Preparation

Place the whetstone in water if it is a water stone. Most Japanese stones need to be soaked until no more air bubbles rise to the surface. Place the stone on a non-slip surface, such as a damp cloth or a dedicated holder. Also keep a small container of water nearby to keep the stone moist while sharpening.

Step 2: Coarse sharpening

Start with the coarse side of the stone. Hold the knife at the desired angle against the stone. As a rule of thumb, placing two coins on top of each other on the stone gives you an angle of around 15-20 degrees. Move the blade across the stone from the heel to the tip using light pressure, as if you were trying to slice a thin layer off the stone. Repeat this process around 10-15 times.

Step 3: Feel for the burr and change sides

Carefully run your finger over the side of the edge facing away from the stone. You should feel a fine, folded-over edge – the burr. This burr shows that you have removed enough material from the first side. Once you can feel the burr along the entire length of the blade, change sides and repeat the process until the burr has moved to the other side.

The ability to sharpen a blade transforms a simple tool into a precise extension of your hands and your will.

Step 4: Fine sharpening

Now switch to the fine side of the whetstone. Repeat the entire process using less pressure. The aim of fine sharpening is to remove the scratches from coarse sharpening, polish the edge and minimise the burr. Keep the stone moist.

Step 5: Stropping and testing

To remove any remaining burr, draw the blade over a leather strop or a piece of hardwood a few times. Alternatively, you can carefully draw the blade through a wine cork. To test it, try cutting paper: a sharp knife should glide effortlessly and cleanly through a sheet of paper.

How do you care for your knives and tools properly?

The sharpest edge is of little use if the blade is not cared for properly. A few simple rules will help ensure a long service life and lasting sharpness.

• Cleaning: Always clean knives by hand with warm water and a little washing-up liquid. The aggressive salts and heat in the dishwasher attack the steel and make the blade blunt.
• Drying: Dry your knives and tools thoroughly immediately after cleaning. This prevents flash rust and corrosion.
• Storage: Never store knives loose in a drawer. The blades knock against one another and become blunt. A knife block, magnetic strip or blade guard is a better option.
• Cutting surface: Always use wooden or plastic chopping boards in the kitchen. Glass, stone or metal surfaces are harmful to every sharp blade.

By taking knife and tool sharpening into your own hands, you gain not only independence but also a deeper understanding of your equipment. A sharp tool is a pleasure to work with and guarantees clean, safe results. Take the time – it is worth it.

Frequently Asked Questions

What is the right angle for sharpening a knife?

15-17 degrees is ideal for Japanese kitchen knives and filleting knives. European chef's knives require 18-22 degrees for a good balance of sharpness and durability. Sharpen pocket and outdoor knives at 25-30 degrees, while axes and machetes require a robust angle of over 30 degrees.

How often should you sharpen knives?

This depends on how often the knife is used and the quality of the steel. Ideally, hone a chef's knife before each use and sharpen it every few months. Sharpen tools such as garden or pruning shears as needed or at least once per season to ensure clean cuts.

What is the difference between sharpening and honing?

When honing (or stropping), you realign the blade's fine, folded-over burr with a honing steel without removing material. This maintains the sharpness. When sharpening, on the other hand, you remove material with a whetstone to create a completely new, sharp edge.

Can you sharpen serrated knives yourself?

Yes, it is possible, but it requires special tools. You need a tapered or round sharpening rod that fits into the individual serrations. Each serration is worked on separately. This is more time-consuming than sharpening a plain edge and requires patience and precision.

Which whetstone do I need as a beginner?

A combination whetstone is ideal for beginners. It offers two sides with different grits. A coarse side (e.g. 400 or 1000 grit) is used for pre-sharpening and creating the edge, while the fine side (e.g. 3000 or 6000 grit) is used for polishing and stropping.