Sharpening and honing knives
A sharp knife is safer, faster and kinder to food. Learn to hone between uses and sharpen on a whetstone when the edge has truly gone.
Why it works
A knife edge is two very thin planes of steel meeting at a line. Under a microscope a working edge is never perfectly straight. With use, the thinnest part rolls over to one side or the other, like the tip of a blade of grass bending. The knife still has metal at the edge, but it now meets the food at the wrong angle, so it feels dull and skids on tomato skins.
Honing fixes that rolled edge. A steel or ceramic rod pushes the edge back into line and removes almost no metal. It takes ten seconds and you can do it every time you cook. Sharpening is a different job. It grinds away steel on an abrasive stone to create a fresh edge where the old one has worn, chipped or rounded. You only need to do it every few weeks or months.
Most knives that feel blunt only need honing. When honing no longer brings the edge back for more than a few minutes, the metal at the apex has worn away and it is time for the stone. Sharpening works by grinding both sides until they meet cleanly, which you confirm by feeling a burr, a tiny wire of metal pushed over to the opposite side. Raise a burr along the full length, then remove it, and the edge is new.
A sharp knife is the safer knife. It goes where you aim it with little pressure. A dull one needs force, slips off skins and lands on fingers.
What you need
- Combination whetstone: A 1000/6000 grit two-sided stone covers most home kitchens; add a coarse 400 stone if you inherit badly damaged knives.
- Damp cloth or stone holder: Stops the stone sliding while you work, which matters more than any other detail.
- Honing rod: Ceramic rods are gentler and suit harder Japanese steel; grooved steel rods suit softer Western knives.
- Permanent marker: Colour the bevel so you can see exactly where the stone is removing metal.
- Flattening plate: A coarse plate or sheet of wet-and-dry paper on a flat surface keeps the stone level.
- Leather strop or folded newspaper: Polishes off the last of the burr after the finest stone.
Step by step
Test the edge
Rest the knife on a ripe tomato and draw it back without pushing down. A sharp edge bites straight into the skin. A dull one skates. You can also slice down through a sheet of printer paper held by one corner: a sharp knife cuts cleanly, a dull one tears or snags at the worn spots.
Tip: Look straight down at the edge under a bright light. Worn or rounded sections reflect light as a thin bright line; a sharp edge shows nothing.
Try honing first
Hold the rod vertically with the tip resting on a damp cloth on the board. Set the blade against it at roughly your sharpening angle and draw it down and towards you, heel to tip, with very light pressure. Alternate sides for five or six strokes each. Test again on the tomato; if it bites, you are done.
Tip: Speed and force do nothing for honing. Light, even strokes give a better result than dramatic flourishes.
Prepare the stone
Soaking stones need 10 to 15 minutes in water, until they stop releasing bubbles. Splash-and-go stones only need a wet surface, so splash water on and keep it wet as you work. Set the stone coarse side up on a damp cloth or in its holder, with the long side facing you.
Tip: Never leave a splash-and-go stone soaking for long periods; some are resin-bonded and can crack or soften.
Find and hold the angle
Aim for about 15 degrees per side on Japanese knives and about 20 degrees on most German and Western knives. Fifteen degrees is roughly the height of two stacked coins under the spine of an average chef's knife. Colour the bevel with marker, take a few strokes, then look: if the ink is gone right to the edge, your angle is correct.
Tip: If the ink only wears near the spine side of the bevel, lower the spine. If it wears only at the very edge, raise it slightly.
Raise a burr on the first side
Place the fingertips of your free hand flat on the blade near the edge to apply gentle pressure. Push the blade across the stone edge-first, sweeping from heel to tip so every part of the edge meets the stone. Work in sections if the knife is longer than the stone. Keep going until you can feel a slight rough wire along the opposite side when you draw a thumb gently off the edge, from spine towards edge, along its whole length.
Tip: The burr must run from heel to the very tip. The tip is where most people stop short, and it is the part you use most for fine work.
Work the second side
Turn the knife over and repeat with the same angle until the burr flips back to the first side, again along the full length. Use roughly the same number of strokes as the first side so the edge stays centred.
Tip: Single-bevel Japanese knives such as yanagiba and deba are sharpened mostly on the front side, with only a few flat strokes on the back to remove the burr.
Move up the grits
Rinse the blade and switch to the finer side or the next stone. Repeat the process with lighter pressure, raising a smaller burr each time. Each finer grit replaces the scratches of the one before with shallower ones, which leaves a smoother, keener edge.
Tip: Skipping from 400 straight to 6000 makes the fine stone do a coarse stone's work. Go 400 to 1000 to 3000 or 6000.
Remove the burr
Finish on the finest stone with a few very light alternating strokes, one per side, edge trailing so you pull the edge away rather than pushing into the stone. Then strop on leather or folded newspaper, always spine first so the edge trails. If a burr is left behind it will fold over within minutes of use and the knife will seem dull again.
Tip: A gentle draw through the end grain of a wine cork or soft wood pulls off a stubborn burr.
Clean and test
Wash the blade with warm soapy water to remove grit and metal filings, then dry it thoroughly. Repeat the tomato or paper test along the whole edge. Rinse the stone, let it dry fully at room temperature, and store it flat.
Whetstone grits
| Grit | Purpose | When to use it |
|---|
| 220–400 (coarse) | Removes metal quickly; repairs chips and reshapes the edge | Badly neglected knives, chipped edges, broken tips |
| 800–1000 (medium) | Creates a new working edge | Routine sharpening every few weeks to months |
| 3000–6000 (fine) | Refines and polishes the edge | After the medium stone, for a keen, smooth edge |
| 8000 and above (polishing) | Mirror polish, very fine edge | Optional; best for hard Japanese steel and slicing knives |
Sharpening angle by knife type
| Knife | Angle per side | Notes |
|---|
| German and most Western chef's knives | about 20° | Softer steel; a wider angle keeps the edge durable |
| Japanese gyuto, santoku, petty | about 15° | Harder, thinner steel holds a finer angle |
| Single-bevel Japanese (yanagiba, deba) | follow the existing bevel | Lay the whole bevel flat on the stone; back is kept flat |
| Cleavers and heavy choppers | about 25° | Robust edge for bones and hard squash |
| Serrated bread knives | match the factory bevel | Sharpen each scallop with a tapered rod |
Troubleshooting
I sharpened for ages and it is still dull.
You almost certainly never raised a burr along the full edge, usually because the angle was too high or too low. Use the marker trick to check, and keep going on the medium stone until you can feel the burr from heel to tip. Only then move to the finer grit.
It was sharp after the stone but went dull within a day.
The burr was left on and has folded over, or broken off and left a ragged edge. Finish with lighter alternating strokes on the fine stone and strop spine first. A few strokes on a honing rod after the first use helps too.
The tip has gone rounded and blunt.
Most people lift or rush at the end of each stroke, so the tip gets less work. Raise the handle slightly as you reach the curve so the tip stays flat on the stone. Check the burr at the tip before you move on.
The stone has a dip in the middle and the knife rocks.
Stones wear hollow with use, which ruins your angle. Flatten it by rubbing it on a flattening plate or on wet-and-dry paper taped to glass until a pencil grid drawn on the surface disappears evenly. Use the whole surface of the stone as you sharpen to slow the wear.
My honing steel seems to make it worse.
The angle is too steep or the pressure too heavy, which grinds a second, blunter bevel. Use the same angle as your sharpening and just the weight of the knife. Hard Japanese knives can chip on grooved steel rods; use a fine ceramic rod instead.
I see small chips along the edge.
Hard, thin Japanese steel chips on glass boards, bones, frozen food or a twisting cut. Grind on a coarse stone until the chips are gone, then work up the grits as normal. Keep hard-steel knives away from bones and use a heavier knife for those jobs.
Sharpening safely
Most sharpening injuries happen when the stone moves or the hand gets in front of the edge. Set up properly and work slowly.
- Put the stone on a damp cloth, a rubber base or a holder so it cannot slide or rock.
- Keep the fingers of your guiding hand on the flat of the blade, behind the edge, and never in its path.
- Feel for the burr by drawing your thumb from the spine towards the edge, never along it.
- Wash and dry the blade after sharpening to remove fine metal filings before it touches food.
- Store knives in a block, on a magnetic strip or in edge guards, never loose in a drawer.
