A whetstone is the superior way to sharpen your knives. This tool completely reshapes the entire edge of the blade in the same way as it was first sharpened in the factory.
Cook's whetstones are quite different from engineer’s oil stones. The kitchen versions are finer and less aggressive than the workshop knife sharpeners. An engineer’s stone must be lubricated with mineral oil while a cook’s whetstone needs to be soaked in water for a few minutes to create a smooth sharpening action. Always use a cook's/chef’s whetstone for best results with your kitchen knives. Whetstones are usually made from a hard compressed material such as silicon carbide or aluminium oxide and they are available in different levels of roughness known as ‘grits.’
The lower the grit number (such as 240 grit) stone will be very rough. and this kind of stone will put the shape back onto the edge of a very blunt knife, plus it will be very good at removing small nicks and chips from the cutting edge too. A finer grit (such as a 1000 grit) stone is very versatile and will produce an excellent cutting edge with ease - the smoother grit stones (3-8000) are for super-fine honing and extreme sharpness.
Diamond whetstones are also available. They are more aggressive than mineral stones for quicker knife sharpening. A diamond stone only requires a small amount of water on the surface to lubricate the sharpening action rather than prolonged soaking. Whetstones are favoured by Japanese chef's, who only ever use these to sharpen their knives as their cuisine is reliant on food being very finely sliced, so they need to maintain the optimum levels of sharpness. Only a whetstone can achieve the super fine cutting edges necessary for this type of cooking.
How to use a Whetstone
- Always soak the whetstone in cold water for at least 10 minutes before sharpening. This allows water to penetrate the stone and provide continuous lubrication for the knife throughout the knife sharpening process.
- Hold the knife diagonally across the stone with the cutting edge towards you, in your right hand, use your right thumb to steady the heel of the knife.
- Place your index and middle fingers of your left hand near the tip of the knife. Hold the knife at the correct elevation to the stone.
- With the cutting edge in contact with the stone, lift the back of the knife to the following degree angles.
- European knife – 35° (European knives are sharpened at a broader angle to maintain the strength of the cutting edge) Japanese knife - 15° (Guide clips are available for use with oriental knives. The clip fits onto the back of the knife and maintains the correct angle between the knife and the stone during sharpening.)
- Draw the knife forwards and backwards over the surface of the stone in a smooth sweeping motion, exerting a gentle downwards pressure.
- Use a sweeping stroke to sharpen the curved part of the knife, ensuring you maintain a constant angle between the knife blade and the whetstone.
- After 30 seconds of sharpening, run your fingers down the upper face of the knife. You should feel a ridge of steel or ‘burr’ running along the knife edge. If the burr isn’t there, continue sharpening for another 30 seconds.
- As you sharpen your knife, the water and powder ground from the whetstone will collect on the stone and your blade. Do not wash or wipe this off – this is the material which sharpens the knife blade.
- You have finished sharpening one side of the knife when you can feel a burr running along the entire cutting edge. You now need to sharpen the other side in the same way. To do this, hold the knife in your left hand and bring the fingers of your right hand down onto the blade in a mirror image of the way that they were positioned while sharpening the first side.
- Repeat the above on both sides of the blade, going from one side to the other until your knife is sharp and there are no burrs on either side.