Urban legend or reality?

2brothers said:
I'd like to know how many knives you folks are using in a day that you need a dishwasher to get them clean.
Do you wait until the end of day after cutting up food, tires and boxes before you clean it?

**Please move to W&C where this can be answered appropriately. :D**
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I haven't used a dish washer in over 6 years, I used to when I was married though. ;)
 
Ankerson said:
the plates etc went. It never dulled them and they were cheap knives back then.
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:) Ironically, cheaper knives have more Cr and a lot less C in them. Also, I suspect those knives were not sharpened to 10 per side or something really sharp anyway.
 
In A. G. Russell's catalog, I'll quote, "water and detergent driven at high speed will dull your blades". Maybe someone with a dishwasher can do a test.
 
Dishwashers will suck the life out of a wooden handle. That much is fact. Hot water and harsh chemicals will accelerate natural corrosion at the very blade edge. Abrasives used in automatic dishwashers will abrade the very edge. Both actions will deteriorate the sharpness of a knife. Add to that the edges being rattled around as the water moves them. I know that I can hear dishes moving around in our dishwasher as it runs, and they are rather heavy plates. No good knife should be put in the dishwasher, or left in a sink of water for that matter.
 
Some of the dishwasher detergents used contain abrassives such as salt and the motion of the water causes movement that can cause the blade to come into contact with other metal. So in theory it is possible.
 
I know the correct answer.

Everyone is heading in the wrong direction answering this one.

The truth is your wife is always right (I've been married only 2 years and already learned that.)

Therefore.... putting knives in the dishwasher does dull them.
;)
 
I've worked as a Pastry Chef for several years and have run all manner of folders through a few different industrial dish-washing machines. I've not noticed any significant edge loss just from being in the machine and being subject to water/detergent spray.

Note that none of the items commonly washed exhibit any damage from washing in the dishwasher. If the water/detergent spray was really enough to damage the edge of a knife then we would see all manner of damage to our flatware and cooking utensils. But we don't. The glassware is just as clear and shiny as when new, utensils, plates and silverware are the same. I feel whatever detergent abrasives there are present in the dishwashing liquid aren't enough to damage the edge.

It is an urban legend because just being put into the dishwasher does not dull the edges, it's contact with other metal items in the washer that causes the damage. Which we already know. Although, to be fair I really think we should call it an Old Wives Tale. :D

Just one cookie's opinion. ;)
 
I know a dishwasher can adversely effect wooden handles. I had to refinish the handles on an entire set of my daughter-in-laws knives.

I can't actually tell if the edges are effected. But for the extra 30-45 seconds that it takes to wash my knives by hand, why take the chance?

Ben
 
We can exclude "banging" element, which isn't worth debating, as it is a fact and new dishwashers do have separate tray for knives and other small utensils.

However, does corrosion dull edges? It does.
Do Hot water and chemicals accelerate corrosion? Yes they both do, add there hot air in the dishwasher which most of the people use, and you have 3 elements attacking the steel.

It is basic high school chemistry, heat, pressure and surface area all affect reaction speed and in this case they're all increasing it. Which means corroding metal faster, and that in turn means dulling it faster.

BTW, if you have noticed, a lot of manufacturers stopped using the term "stainless" and started using more correct "stain resistant". That wasn't done because of the correctness, but because people stick their "stainless" knives in a dishwasher and then when they get rust spots complaints follow....
 
Hitting ceramics and metals should be bad not to mention.

The other thing I'm worried about is temperature.
If your concerning blade is made of straight carbon steel and
the washer has considerable high temperature through the drying step,
it can ruin the temper of the blade.
Even water boiling temperature can ruin the heat-treatment of straight carbon steel
if repeatedly applied.
 
Dishwasher detergent is abrasive. I have seen plenty of wine glasses that have been etched, coffee mugs that have lost their humorous logos, and flatware that has lost its sheen. Spoonrobot, it seems to me that consumer dishwashers are harder on cutlery and crystal than the professional versions used in restaurants. These seem to be much more efficient. My dishwasher runs for almost an hour, recycling the water, detergent and food particles as it cleans the dishes.

My knives don't go in.

Joe
 
fujita yuji said:
If your concerning blade is made of straight carbon steel and the washer has considerable high temperature through the drying step, it can ruin the temper of the blade. Even water boiling temperature can ruin the heat-treatment of straight carbon steel if repeatedly applied.
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Really? :confused:
 
I wouldn't put a single knife that i valued at all in the dishwasher. Stainless steel can rust after a couple of washes sadly. Once in a while, maybe. Though, if you really like the knife, just hand wash quickly and there won't be anything to worry about.
 
hlee said:
Dishwashers will suck the life out of a wooden handle. That much is fact. Hot water and harsh chemicals will accelerate natural corrosion at the very blade edge. Abrasives used in automatic dishwashers will abrade the very edge. Both actions will deteriorate the sharpness of a knife. Add to that the edges being rattled around as the water moves them. I know that I can hear dishes moving around in our dishwasher as it runs, and they are rather heavy plates. No good knife should be put in the dishwasher, or left in a sink of water for that matter.
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Amen brother, testify!
 
yea industrial washers use a liquid wash fluid where as the domestic washers use eather a powder or something with abrasives in it. also an industrial washer lasts like 3 min at most. where home washers as said before can go for close to an hour. lots more wear and tear on a blade in a home washing machine than an industrial one.
 
fujita yuji said:
Hitting ceramics and metals should be bad not to mention.

The other thing I'm worried about is temperature.
If your concerning blade is made of straight carbon steel and
the washer has considerable high temperature through the drying step,
it can ruin the temper of the blade.
Even water boiling temperature can ruin the heat-treatment of straight carbon steel
if repeatedly applied.
Click to expand...
I don't know what dish washers you use, but to start to affect the heat treat, you need to go past 150degrees C/300degrees F for atleast 1 hour.
 
I know that some dishwasher additives contain citric acid or they are completely citric acid and I think this could damage almost any knife blade steel put into them ... on the other hand ... though my wife puts the general kitchen knives in the dishwasher my kitchen knives are stored separately and always hand washed and dryed. I hate a knife in the dishwasher but what can you do??
 
Roger999 said:
I don't know what dish washers you use, but to start to affect the heat treat, you need to go past 150degrees C/300degrees F for atleast 1 hour.
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You're right for this condition.

Honestly, I didn't see that effect in person, nor I can't find any document
mentioning what I said in my previous post. So I cold be wrong.
I meant as long as several months or years of repeated application.
 
I'm with the AG catalog. No diswasher and avoid soaking for any lenghth of time. Just a quick swipe of the dishrag, (preferably not along the razor sharp edge) and dry imidiately.
 
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