Digested Digest: Knives Out – A Guide to Knife Sharpening

Irish bladesmiths are seemingly in high demand. If you have managed to get your hands on an Irish-made knife of late, you deserve to be congratulated. Either you are remarkably patient, have something of bartering value or have connections on the inside (all of which are valuable assets in themselves). The upsurge in demand can be attributed to a few factors:

1. The pandemic got us back into the kitchen and subsequently, we realised our kitchen and equipment required immediate updating.
2. We now value process and craft over materiality. The urgent requirement to think sustainably has caused us to want fewer things and refocus on better quality things.
3. Irish pride is at an all-time high as we gather the courage to carve a path of our own. A knife is a tangible method of connecting with our ancestral roots and traditions. After all, is there anything that induces our primal needs more than the gift of a blade?
4. There are at least three (maybe more) expert knife makers in Ireland, producing blades of the highest quality. And so, as we swap iPhone for mammoth tusk and 14 carat gold for 16 layers of Damascus, nothing eclipses the primeval sensation of drawing a blade from a hand-crafted saya…

However, there comes a moment when a knife’s edge no longer cuts through a mushroom and so if you wish to avoid just having a blunt carbon artwork, it is time to sharpen. Just like making sourdough, knife sharpening is an eternal skill. It’s a process that improves with practice and unlike sourdough, it won’t die in your fridge. Now, let’s get to work.

Sharpening explained 

Out of the box, regardless of its quality, almost every knife is sharp. However without proper care and maintenance, whether you spend €10 or €500, after a matter of weeks of continuous use, the knife will dull. What differentiates knives from good to bad or high to low, is the quality of craftsmanship (most significantly, quality metals and the forging of metals). This, of course, dictates the knife’s ability to hold an edge. Without learning to properly sharpen your knife, spending big is simply not worth it. To be honest, I have ruined many knives over the years, mainly because I hadn’t learned how to take proper care of them.

Stones vs honing steels 

When you cut and slice food, the edge (or bevel) of the knife begins to dull. Not only that, it actually begins to bend and microscopically curl, causing the knife to become entirely dull. This bend is called a burr. The purpose of a sharpening stone is to remove that burr by removing a layer of the metal and subsequently realigning the edge.

A honing steel works differently. Although most home cooks refer to a honing steel as a ‘sharpening steel’, the honing steel is not designed to sharpen at all. Its purpose is to realign the bevel (knife’s edge) as it begins to bend left or right (which will naturally sharpen the knife temporarily). If the knife’s edge is allowed to bend and roll over, the honing steel becomes entirely useless and your knife is in need of a stone.

After a knife has been realigned with a stone, the edge can be maintained through application of the honing steel temporarily, or until the knife requires a fresh application on the stone.

Types of stones 

Medium grit (1000- grit): the most used grit for knives and best for removing small burrs.

Low grit (5000+ grit): these stones are for finishing your knives following the 1000 grit. They will refine your blade, making the knife sharp for longer.

Very low grit: (200 grit): low grit stones like these are for damaged blades that require a full removal of metal. They should be used with caution and only when the knife is in bad condition and requires a new edge (chips).

Advice for beginners

Knife sharpening is a bit of a knack and takes a bit of practice to get used to but after a while, it will feel like second nature. There are several steps to sharpening, taking into account the ratio, followed by finishing and stropping. Despite inevitable impatience, my advice is that you start with a cheaper knife to learn on. There’s a high probability you will not get the angles right to begin with.

How to sharpen your knife using a stone: (step by step).

1. Begin by soaking your stones in cold water for at least 20 minutes (overnight is perfect but not necessary).
2. On your workbench, set your soaked stones on a folded damp cloth or on a sharpening base if you have one.
3. Have a small container of cold water next to you. This job is a little messy so perhaps wear an apron.
4. Wet the stone a little with water (1 tsp worth is fine).
5. Place the knife flat on the stone with the blade facing you. Hold the handle with your chopping hand and place the tip of your knife on the side of the stone nearest you. Place your index finger and middle finger where the edge of the blade meets the stone, so that they are in contact with both the blade and stone.
6. Raise the knife to find the angle of the bevel. There is a thin line running from the edge of the knife base to the tip. You should be able to feel it as you lift the knife from flat upwards. You want to make sure this part of the knife is flush with the stone. A sharpening stabiliser might help you with this.
7. Applying pressure upon the blade, slide the knife up the stone. Release the pressure a little on the way back towards you. Inch your fingers down the knife as you sharpen the entire face of the blade in sections. Repeat this process, edging down the entire knife.
8. As you work the blade on the stone, fragments from the stone will appear, mixing with the water, forming an abrasive lather. The abrasion between metal and stone is what causes the sharpening.Flip the knife so the face of the blade is towards you. Find the bevel, making sure it is flush with the stone.
9. Apply the same technique but this time, apply the pressure when drawing the knife towards you.
10. Repeat the process on either side until satisfied, ensuring you keep the angle at all times. Refer to the ratio below.
11. Wipe the knife clean and move on to a finer grit/ and or stropping (see below).
12. To store your stone, wipe clean with a towel and allow to air dry before storing. This will prevent the stone from cracking.  

Ratio 

Now onto the ratio of your bevel. My 210mm Gyuto knife by Japanese bladesmith Takamura has a 50/50 ratio, meaning that I should sharpen the knife equally on both sides. Some knives like Japanese sashimi knives are single bevel, meaning they are to be sharpened only one side. I have other knives that are 70/30. The 70/30 edge is an asymmetric sharpening method for DOUBLE BEVEL knives. Sharpen MORE on the side of the dominant hand, producing a secondary bevel that’s visibly about twice the size. Also, sharpen at a GREATER ANGLE on the dominant side – about double the angle

Finishing stone 

When you are satisfied with the sharpening, you now need to use finishing stones. These stones have higher grits and are finer, making your knife’s edge more durable. Apply the same technique for the lower grits.

Stropping 

A leather strop will put a final finish on the edge of your knife. Its purpose is to further refine your edge. You can purchase a belt or a strop stick. Both work extremely well, and bring a remarkable finish to your knife. You only need to apply a few strokes to each side of your knife. Again, this is not essential but thoroughly recommended for those looking to get their knives razor sharp.

Equipment 

• 1000 grit stone – essential 
• 5000-8000 grit stone – essential 
• Leather strop – non essential but highly recommended.
• Ceramic honing rod – recommended for maintenance.
• Lapping stone and dressing stone – these are for levelling and cleaning your stones. Non essential but worth investment if you want to take care of your stones (more on this below).
• Sharpening stone base – not essential and a damp cloth also works.
• Sharpening stabiliser tog grip – recommended for beginners.  
• Oil – not essential but good for preventing carbon steel knives from rusting and for mirror polished knives.

What not to use: 

• Diamond steels – diamond steels will ruin your blade. While they will sharpen your blade quickly, they are extremely harsh on soft steel Japanese knives, causing an undesirable bow effect.
• Honing steel – same as above (they are really only useful for realigning German knives).
• Cheap stones – you often see stones available in hardware stores. Be sure to purchase your stones from reputable knife shops.

How to protect your blade:

• Keep your knife dry.
• Don’t put it in the dishwasher (it can cause rust and the knife can hit off other objects and chip).
• Avoid cutting through hard objects that will dull or chip the blade (bones).
• Avoid foods like tomatoes (use a serrated knife instead).
• Use a saya. A saya is basically a scabbard. It protects your knife when not in use. It is really handy for transporting knives. If you don’t have a magnet, a saya allows you to store your knives in drawers or in utensil vases on your counter. Alternatively, you can make a temporary saya by wrapping newspaper around your knife and reinforcing it with tape.

Taking care of your stone 

• Lapping stone – a lapping stone is used to keep your whetstone flat. As you sharpen your knife, naturally you remove material from the stone, causing the stone to become irregular. In order to correctly sharpen your knife, you need a flat surface.
• Dressing stone – a dressing stone’s purpose is to clean a stone of any slurry that forms during sharpening. Failing to remove this built-up matter prevents the knife from coming into contact with the abrasive quality of the stone and you won’t be able to sharpen the knife as effectively.

Words: Cúán Greene

Cúán Greene is a chef and author of the Ómós Digest Newsletter.  You can subscribe for weekly posts at omos.substack.com