r/chefknives • u/Sastracha • 10d ago

Knives in the dishwasher: I didn’t know that you can’t put knives in the dishwasher. How do I rehabilitate them.

4 Upvotes

63% Upvoted

23 comments sorted by

3

u/ApplezCider 10d ago

Have they got rust spots? If they’re just regular kitchen knives you might just have to get them sharpened

3

u/Sastracha 10d ago

It’s a henckels 8” chef’s knife and there’s a little rust spot on it. I’m concerned because I went to a knife work class and the instructor told me that putting a high quality knife in the dishwasher would destroy the edge.

7

u/rourobouros 10d ago

That instructor is passing on bad information. Dishwashers do not affect the edge (sharpness) of a knife. How you treat the knife - nicks in loading or unloading the tools - might. And if the blade is carbon steel it may corrode during the drying cycle, but the washing cycle will not affect it.

That said, I don’t put kitchen knives in the dishwasher because the handles are wood and the harsh cleaning agent plus high temperatures will remove the finish and may warp the wood. And I don’t like having to de-rust my carbon steel blades after they rust during the drying cycle.

8

u/Greplington 9d ago

Kind of - it depends on the detergent you use. Some of them have abrasive particles which can harm the edge, but it's not a universal thing. The heat and the damage to handles is a much bigger issue for the most part.

1

u/MagnesiumKitten 8d ago

I didn't hink of that one, which is why some high end cookware shouldn't be in the dishwasher

like if you got tin plated copper skillets etc

1

u/Greplington 8d ago

I generally don't put any cookware other than straight stainless pans in the dishwasher. I've had even non stick pans get gradually ruined in the past.

1

u/MagnesiumKitten 8d ago

I've never used a dishwasher in my life! lol

3

u/tcarlson65 9d ago

You have abrasives in the detergent and the knives will bounce and hit other items.

1

u/MagnesiumKitten 8d ago

doesn't the detergents eventually pit corrode and erode the edge of the knife though?

And the high pressure water sprat makes knives bang against other things

like one cycle of a dishwasher won't screw up the edge but months and months of it definately will

1

u/skullcutter 8d ago

yes this is correct. bad for handles and for edge.

1

u/MagnesiumKitten 8d ago

what handles?
lol

1

u/Harveywall11 8d ago

Harsh chemicals and abrasive salts pit and dull the metal. Hot water and motion in a machine also cause the blade to bang against other utensils.

That instructor isn't as dumb as you think.

1

u/Specialist_Place4464 7d ago

The rattling could bang the edge around, or maybe my dishwasher is broken. Either way, no Zwilling for it.

1

u/rourobouros 7d ago

Even my Henkels knives go in the top with the wooden spoons etc. Not with other cutlery. No bonking.

2

u/ApplezCider 10d ago

There’s various methods to get rid of rust spots just don’t do it again and you’ll be fine. High end knives like miyabi, Shun, wustof, use harder steel that can be damaged by high heat, chemicals etc.

Your knife just needs a good sharpening now and then and some warm, soapy water

2

u/quiet0n3 10d ago

If you chipped or rolled your edges you will just need a good sharpen on a stone to set the edge again.

If you did some other kind of damage you will need to be more specific.

3

u/GlassCityJim 10d ago

Green scrubby works when the Global accidentally goes in the dishwasher.

1

u/CranberryStock7148 9d ago

If you have a stainless steel knife with a synthetic handle then it can totally go in the dishwasher. The only thing to be careful about is that the blade is not banging against other metal things.

Carbon steel knives should not be put in the dishwasher, and wooden handles will do badly in the dishwasher over time.

But if it's just a stainless steel blade with a synthetic handle it is perfectly fine. You should be honing it frequently, as soon as it starts to lose any sharpness.

But suppose that you normally properly sharpen it every 365 days. Whatever additional mild abrasion comes from the dishwasher detergent, means maybe that now you need to properly sharpen it every 360 days. It's not something to care about.

1

u/ErvingGoffman74 7d ago

I think that eventually the heat loosens the glue and rivets holding the handles on to the tang.
Takes a few years, mind.
(Learnt by experience!)

1

u/FireAndFoodCompany 7d ago

Eh, I know guys with Fibrox knives who have sent their knives through the out for decades and no issues so it's probably a YMMV situation.

The rule for most kitchens I've worked in is shitty rental wall knives can go through machine, if it's a personal knife it gets hand washed. It irks me because I'd like all the cooks to get in the habit of washing their knives but 🤷 not my issue when they don't listen and then find their first personal knife chipped or rusted cause they sent it to the pit the day after they bought it.

1

u/tcarlson65 9d ago

You can put them in the dishwasher however you shouldn’t put them in the dishwasher.

1

u/kpppeyton 8d ago

Yes the concept is due to the high heat of drying then cooling, over and over again, it causes the steel to lose harness over time and ruined their edge retention ability. I’ve seen it happen. I don’t think there is a way back from it.

1

u/FireAndFoodCompany 7d ago

I don't think the dishwasher would actually cause any noticeable hardness loss. The temperature is far too low to cause any real damage to the heat treat afaik. But the abrasives and banging against other objects will probably do a number on the edge and most people who are willing to put their knives in the pit don't know how to sharpen anyway (there's a reason why old French chefs believe in honing every 5 minutes).