Why Do Knives Go Blunt? The Four Real Causes
A knife does not go blunt from cutting, it goes blunt from everything else. The edge is a few hundredths of a millimetre wide — it survives tomatoes without trouble. What kills it usually happens alongside: on the board, in the drawer, in the dishwasher.
1. The edge folds over
This is the most common cause and it is not wear. The very outermost edge bends sideways — under a microscope you see a folded flag, not a worn-away edge.
The knife feels blunt but is still entirely there. A honing steel realigns an edge like this without removing material. That is exactly what it is built for — and all it is built for.
When the honing steel stops helping, the edge is not folded over but gone. Then it needs sharpening.
2. The cutting board
This is where most real wear happens. Every cut ends on the board, and the material decides what happens to the edge:
- Wood and plastic: they give way, the edge sinks in briefly. Gentle.
- Glass, stone, ceramic, marble: they do not give way. The edge is compressed on every cut. A glass board will blunt a new knife in a few weeks.
- Metal: stainless worktops, baking trays, plates. A single cut is enough for a visible nick.
If you change only one thing, change this: get rid of glass boards. It does more than any sharpening tool.
3. Storage
Knives lying loose in the cutlery drawer knock against forks, spoons and each other every time it opens. The edge is the most delicate part and sits exactly where the contact happens.
A knife block, a magnetic strip or a blade guard — any of these noticeably extends the time between sharpenings. It is the cheapest step of all.
4. The dishwasher
Three things come together: the blades knock against other cutlery in the basket, aggressive detergents attack the surface, and the heat dries out the handle.
Our VG2 models are dishwasher safe — good kitchen knives usually are not. A quick rinse and dry takes twenty seconds and saves you half the sharpening.
What people wrongly blame
- "Hard food." Carrots, pumpkin, bones in the soup — not the problem, as long as you do not cut through the bone.
- "Cheap steel." A soft steel goes blunt faster but also sharpens faster. A hard one lasts longer and is more brittle. Neither is "bad".
- "The knife is old." Age does not blunt anything. A blade from the seventies is as sharp as on day one after five passes — as long as there are no chips in it.
What this means for your sharpening rhythm
Fix the four causes and you will sharpen far less often — but never never. Material comes off; that cannot be prevented, only slowed.
So the best rhythm is not "when it is blunt" but briefly and regularly. Three passes before you start cooking. An edge that never goes fully dull is back in seconds — a completely dull one needs considerably more material removed.
More on this: How often to sharpen a knife
Common questions
My bread knife never goes blunt. Why?
Because it does not land on the board — it saws through the crust and stops in mid-air. That is why serrated edges last a very long time. They do go blunt, just more slowly. And then you need a tool that reaches the arcs: Sharpening serrated knives
How do I know when it is time?
By how it behaves when cutting, not by how it looks. A tomato whose skin slips away instead of giving in is the most reliable sign.
Does oiling help?
Against rust yes, against bluntness no. Oil protects the surface, not the edge.
In short
Glass boards out, knives not loose in the drawer, not in the dishwasher — and resharpen briefly and regularly instead of rarely and thoroughly. The first three cost nothing.