Why kitchen knives should not be put in the dishwasher

Anyone who owns a high-quality sharp kitchen knife knows how important it is that it is well treated and cared for. Especially professional chefs who cut a lot of meat, fish or vegetables and have to pay attention to accuracy are dependent on one or more professional knives. But also in households where people like to cook and fry a lot, they will appreciate a sharp kitchen knife. Since the sharp blades are very sensitive, they require special treatment. This includes, among other things, that kitchen knives do not belong in the dishwasher. Why? Because they become dull and can no longer cut precisely.

Why do kitchen knives get dull in the dishwasher?

There are several reasons why you should not put your good kitchen knives in the dishwasher under £300.

1st reason: contact with other cutlery

This is how sharp knives in the cutlery basket or even on a cutlery rack come into contact with other knives or other cutlery. The hard water jet from the dishwasher spray arm can cause the knife edge to strike against the other pieces. This can cause the blade to become not only dull, but even more damaged. Nicks and chipping can occur, rendering the knife unusable.

Also of interest: Dishwasher tabs or powder: Which variant works better?

2nd reason: Corrosion

But aggressive ingredients in the rinse water also attack the steel. When you clean your dishes and cutlery in the dishwasher, the water is mixed with the detergent rennet, rinse aid and salt and distributed over everything in the dishwasher at temperatures of 60 °C to 70 °C. This way, food residues are removed from the dishwasher. In this way, food residues are softened and removed over the duration of the program. This can take 2-3 hours, during which your high-quality kitchen knife comes into contact with the aggressive acids and salt.

Over a longer period of time, these ingredients now react with the metal of the blade and cause it to rust. When you put the knife in a dishwasher for the first time, you won’t notice the damage right away, because it will be inconspicuous at first. Only a few small brown spots indicate the damage. Over time, the finely ground edge becomes more porous and tiny pieces on the cutting surface break out – the knife no longer cuts as sharply as it should and it becomes dull.

As you can see, although the high-quality kitchen knives in UK are called “stainless”, they are actually only “rust-resistant”, i.e. they only rust more slowly or under more difficult conditions, such as those that exist when they are washed in the dishwasher under £400. By the way, this has nothing to do with dishwasher-safe or dishwasher-suitable.

Also of interest: Why glasses tarnish in the dishwasher

3rd reason: flash rust

Flash rust is another reason why you should not put your high-quality kitchen knives in the dishwasher deals. This dirt, coming from inferior cutlery or steel pots, can settle on the knives. This does not look very appetizing on the high quality knives.

4th reason: Damage to the handle

Damage also occurs to the handle of the knife over time if you wash it in the machine. Wooden or plastic handles can fade or detach from the blade due to the interaction of detergent, high rinse temperatures and long water exposure time. In this case, too, it is better not to put the kitchen knife in the dishwasher under £500, but rather to wash it by hand.

Also of interest: All about dishwasher programs

Why is it better to wash high-quality knives by hand?

In contrast to washing in the machine, when washing by hand, the knife is confronted only briefly and also with only a little aggressive, less concentrated detergent. And while the dishwasher operates at high temperatures of over 60 °C, only low temperatures of around 40 °C are reached when washing by hand. A professional knife like this, which usually also has its price, thus comes into contact with the damaging components only briefly and not so intensively during hand washing.

  • Experts agree that cleaning by hand is far gentler and therefore better for the condition of the blade. Therefore, when rinsing by hand, proceed as follows:
  • It is best to rinse the kitchen knife immediately after use. Contact with salty or acidic foods can also attack the material.
  • Simply rinse with a drop of washing-up liquid and lukewarm water. A sponge or brush will help.
  • Don’t just let it dry, use a cloth to gently wipe it dry from the back of the blade to the cutting edge. This will prevent you from injuring yourself on the sharp blade.

Also of interest: What is the difference between fully integrated and partially integrated dishwasher?

Where should kitchen knives be stored?

So that the quality does not suffer, kitchen knives do not belong in the dishwasher. But you should also follow a few rules when storing them. For example, the blade should never touch other knife blades. A cutlery tray is therefore rather unsuitable for a high-quality kitchen knife. Better is a knife bag, a knife block or magnetic strips. This way, the knives are stored separately and you don’t run the risk of them being damaged by other parts. It is also essential to sharpen the knives regularly so that they are sufficiently sharp.

Also of interest: Dishwasher descaling – A guide


Kitchen knives become dull in the dishwasher. If you love your knives, you should rather wash them by hand. And even if it says “stainless,” that doesn’t mean kitchen knives can’t rust. In the machine, that can be the case.

David Shaw

David Shaw

Dishwashers expert with over 10 years of experience. He writes articles and shares his knowledge on many sites. Helps you choose the best (portable, countertop, built-in) dishwashers on this site.

Dishwashers Review in UK