What specifically about a dishwasher is damaging to cookware?

[LaureltQ]

Like say an all-clad all-stainless exterior pan?

I could see enamel-coated getting etched or banged up on enamel coated cast iron. Obviously things like carbon steel and cast iron shouldn't go in dishwashers.

How do stainless and nonstick get damaged in the dishwasher short of getting banged up when hitting other items? I also hear this about knives. I have stainless wustof knives, and while I never put them in the dishwasher (too easy to clean by hand and I can't guarantee they won't hit stuff), is the only reason not to put stainless knives in the dishwasher besides the possibility of dulling the edge due to mechanical damage?

[kaleokahu]

Hi, Laurel:

No one has mentioned abrasives. I believe most DW detergent contains a lot of abrasives, and even a little combined with heat and strong detergent is very harsh on what's inside.

IMO, no, banging damage is not the only reason to avoid the DW for SS knives. The wear imparted by the *sandblasting* will selectively prefer the edge and erode and mess up your bevels. You also have to deal with the effects of the DW on handle materials--it's not good to repeatedly scour and bake plastics and epoxy-impregnated materials.

BTW, a DW usually does a mediocre job anyway. Today I started cleaning up a set of 1950s Revereware for another poster (Hi, Lucy!), that I know was run through a DW. 5 minutes with BKF and a Scotchbrite was far superior to *umpteen* times through the DW. By the time it comes off the buffer, it will look almost new.

[Chemicalkinetics]

"Today I started cleaning up a set of 1950s Revereware for another poster (Hi, Lucy!)..."

What? I have some pans too. Can I send them to you? :)

[johnb]

"........Today I started cleaning up a set of 1950s Revereware for another poster (Hi, Lucy!), that I know was run through a DW. 5 minutes with BKF and a Scotchbrite was far superior to *umpteen* times through the DW. By the time it comes off the buffer, it will look almost new....."

This seems to me to not be exactly an appropriate comparison. Nobody expects any dishwasher, including hand washing in the sink, to yield the same results as a thorough scrubbing/polishing with BKF. However, I doubt many folks clean their pots that way routinely, so I doubt it is of much significance.

Also, IMO comments like "BTW, a DW usually does a mediocre job anyway" are particularly incomplete. There is no such thing as "a DW." There are many DW's out there, some old, some new, some cheap, some expensive, some well designed and some not, some well-maintained and some not, some with owners who know how to use them to get good results, and some without (lots of people don't even know how to property stack a DW). There are many DW's that are perfectly capable of doing a good job with pots, and some that aren't. Blanket statements, as so often appear in these topics, really are of somewhat limited value.

[eliz553]

As long as the DW is loaded so that the contents are not scraping against each other, All Clad stainless is not harmed at all by the DW. (I do have a life outside of the kitchen).

I hand wash good knives (99 cent paring knives go in the DW).

Just use common sense.

[E_M]

Certain detergents will etch or pit stainless. We don't use Cascade for this reason.

However, with whatever we do use, we wash everything. Stainless, non-stick (admittedly not a good idea), sterling, aluminum (haven't ruined it...yet), etc.

[johnb]

I use whichever detergent is cheapest, and that often turns out to be Cascade (on sale of course--the other fav is Electrosol). I have washed SS cookware and SS knives, and have never seen ill effects on either. I have some Dexter Russel paring knives (sani-safe) that go thru in every load and over the years have therefore probably gone thru the DW 7-800 times or more and there is no effect whatever. So what is the problem with Cascade?

[LovinSpoonful]

Stainless steel cookware is fine to put in the dishwasher. I have All-clad stuff that has been going in for 10 years or more that is perfect.

Knives are fine so long as a) the handles are dishwasher safe and b) they will not knock against anything. It's the physical banging of the edge that is at issue. As an experiment I tucked a decent and just sharpened Henckels knife in the corner of the dishwasher for like 20 cycles, took it out and there was no discernable damage to the edge, so I put all my stainless knives in there now, when convenient.

DON'T put anodized alum cookware in. I have a ruined Calphalon pot top that will show you how one cycle will take the destroy the finish.

[BruceMcK]

The manager at the Calphalon Culinary Centre told me she can tell if anodized Calphalon has been through the dishwasher just once, and it will void the warranty. Someone I know puts her anodized pots (not Calphalon) through the dishwasher regularly and I was horrified how quickly they went from sexy gray-black to pasty whitish aluminum. I was horrified, but she did not care.

This obviously does not apply to the new generation of dishwasher safe anodized like Calphalon Unison and All-Clad LTD2 (which is soooo cool!).

[Jay F]

Isn't the heat in the DW too high for knife edges, i.e., they "melt" at some microscopic, yet critical, level?

[Eiron]

LaureltQ, who's telling you that stainless steel gets damaged? And what are they saying happens exactly?

Knives: blades will get dull faster due to banging around & caustic detegents, but also handles will suffer. Plastic handles will lose their surface components (plasticizers) from the combination of detergent chemistry & heat of the wash water & drying cycle. Wood handles will succumb even sooner.

[Chemicalkinetics]

Hi LaureltQ,

I agree with Mikie. The detergents used for automatic dishwasher are usually much harsher than the one we use by hand. That said, my impression is that these stainless steel cookware will not be permanently damaged by them. A bit of stain maybe, but nothing cannot be fixed. Now, anodized aluminum cookware is a completely different matter.

[Dave5440]

I couldn't believe what it did to my aluminum parts for my meat grinder , destroyed the finish

[Chemicalkinetics]

Yeah, aluminum is much more reactive than stainless steel. I can totally see that. Probably worse for anodized aluminum than bare aluminum because the anodized surface can be striped off.

So what did you do after that incident? Were you able to fix the part by sanding the affected surface or buy new parts?

[Dave5440]

I ended up buying a new grinder, the motor was starting to smoke on it anyway, and any SS i've ever put in (or left in not intending to run it) has never been affected

[LaureltQ]

This is what I imagined was the case. I can't imagine that there would be permanent damage to SS cookware. I have a junky nonstick pan my mother in law bought us when my hubby and i started dating that has probably only been washed in the dishwasher and it is still in great shape after 5 years. Perhaps that has more to do with how often I use it versus other pans than how it stands up to the dishwasher.

[Chemicalkinetics]

I agree. All Clad (like many others stainless steel manufacturers) claims their Stainless Steel cookware are dishwasher safe:

http://www.all-clad.com/consumer-service/frequently-asked-questions/#faq7

I just looked up the All Clad website (as you can tell above) and surprised to find out that All Clad has made a new line of anodized aluminum cookware which can endure the dishwasher environment. Evidently, All Clad put another layer of "something" to protect the anodized aluminum. Here: "The revolutionary exterior coating technology allows LTD2 to endure the harshness of daily dishwasher":

http://www.all-clad.com/collections/L...

Finally, my vauge understanding is that the newer dishwasher detergents have gotten less aggressive in recent times.

[wekick]

It seems that I have seen kind of an iridescent dark blue damage to a stainless pan at sometime, with something washed in the DW. I can't remember the exact circumstance. Maybe my mom's pans. Would a copper bottom contribute to that? I do wash my KA stainless mixing bowl with no problems, but wash most all pots and pans by hand, do to that memory.

[monku]

Dishwashing detergents are being made with less phosphates to help the environment and not cleaning as well.
http://www.nytimes.com/2010/09/19/sci...

[Dave5440]

In Canada they pulled all the phosphates out, now i'm looking for a water softener just for the dishwasher, 3 passes through everything was covered in a white haze , now i'm putting in a quart of vinegar at the last rinse to stop it , and filled the jet dry dispenser with vinegar as well

[LaureltQ]

So there's actually chemical damage occurring in the dishwasher? I understand that the detergent is rough on finishes, but is it actually damaging? I can't imagine that barkeepers friend is less tough on my all-clad than the dishwasher.

If all of these pans shouldn't go in the dishwasher is the reason that the manufacturers say that the pans are dishwasher safe is to sell more?

[Dave5440]

Yep it really is that harsh

[Philly Ray]

Non-stick cookware should not be cleaned in the dishwasher. The detergent is too harsh.

As for other items, I have read that the reason they suffer in the dishwasher is because we tend put them in too "clean". Since the detergent is looking for something to wash off, it will attack the finish of plates and cookware if there is no grease, food, etc. to clean. Instead of prewashing, just put your stuff in there as is.

[mikie]

Two things come to mind, first mechanical banging around and second and perhaps most importantly the detergent used in a dishwasher is tough on metals of all types.

With regards to the knives, it would be the same thing, mechanical damage banging around with the water jets, but the detergent is also tough on the very fine edge of a knife.

[Dave5440]

I can tell you one pass through the dishwasher ruined 2 of our non-stick pans, not only didn't they work even the finish was noticeably different, i've heard the same thing about the car wash chemicals(the automated ones) dulling the clear coat.