The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Did the KitchenAid dough hook ruin my bread dough?

rissa.85's picture

Did the KitchenAid dough hook ruin my bread dough?

I just made bread dough in the KitchenAid stand mixer and when i was finished i noticed the gray color was rubbing off the dough hook into the dough.  Is it safe to eat or should I throw it away?

yy's picture

Are you saying there's a dark-ish "finish" on the dough hook that is rubbing off into the dough? The same thing happened to a metal kitchenaid dough hook of mine. I contacted kitchenaid customer service, described the problem, and they sent me a new one after conceding that this was not normal. I think you should throw the dough away. It sucks, but who knows what health effects that grayish stuff might have.


rissa.85's picture

Yeah i think it's probly the finish.  It got washed in the dishwasher which I now realize is the wrong thing to do.  I talked to someone from KitchenAid and they're sending me a new one but in the meantime I have this bread dough I really don't want to throw away, just was wondering if anybody knew if the stuff is toxic.  But yeah guess I should toss it to be safe. 

quickquiche's picture

When in doubt, toss it out.

simon3030's picture

Hi, the dough hooks and other beaters are made from cast aluminium; the problem with aluminium is that dishwasher detergents, which are caustic (alkali), react with the aluminium to form the grey oxide that rubs off the surface - once you have dishwashed them, they are irretreivable - so as has been said, toss it out!

thihal123's picture

YUCK! Didn't realise it was made of aluminium. That stuff is reactive! I mean, I don't know many doughs that are that acidic, but what about sourdough? Wouldn't that be acidic enough to react with the aluminium dough hook? Anyhow, I don't use a KitchenAid for breads (though I do have a professional series one).

CelesteU's picture

Why on earth would you THROW OUT a perfectly fine dough hook just because it's been through the dishwasher?  Sure, the shiny alumnium surface has oxidized, but it isn't going to harm you.  Dish-washing aluminum can cause pitting, which is the reason manufacturers suggest hand-washing.  I run my KA beater, whip, and dough hook through the dishwasher once a month or so; after 5 years, I haven't seen any pitting thus far.

Practically every commercial bakery and restaurant in the free world uses aluminum sheet pans and/or aluminum cookware (like AllClad), which are certainly washed in detergent (either by hand or mechanically).  Yes, a light film of oxidation will build up after prolonged contact with detergent & water, but scrubbing & drying will take care of it.

Sheesh, not every substance in the world is toxic.  The negative environmental impact of mining bauxite for aluminum/refining it/manufacturing & shipping are FAR greater than any impact from oxidized aluminum, so KEEP what you have and don't needlessly buy new things.


yy's picture

Sure, the shiny alumnium surface has oxidized, but it isn't going to harm you. . . .Sheesh, not every substance in the world is toxic.  

No, but some substances are.  I would perhaps consult a higher power backed by science before making a judgement on this (maybe Materials Safety Data Sheets or In the absence of more knowledge, I would err on the safer side and assume that it is not safe for human ingestion.

The negative environmental impact of mining bauxite for aluminum/refining it/manufacturing & shipping are FAR greater than any impact from oxidized aluminum, so KEEP what you have and don't needlessly buy new things.

Nobody is trying to be wasteful here, only cautious.

Practically every commercial bakery and restaurant in the free world uses aluminum sheet pans and/or aluminum cookware (like AllClad), which are certainly washed in detergent (either by hand or mechanically).  Yes, a light film of oxidation will build up after prolonged contact with detergent & water, but scrubbing & drying will take care of it.

I personally have used plenty of aluminum sheet pans that develop a discolored finish after a period of use, as you have described. They remain perfectly good and functional. However, in the original poster's case, we're not talking about a cosmetic color change. What the original poster is talking about is different - I have experienced the same thing firsthand from a KA dough hook, and it certainly did not look like an old sheet pan. We're talking about a substance that is rubbing off into food.

I'm not the compulsive, hand-sanitizer-happy, "if you don't eat organic you will get cancer" type by any means. I even eat smoked meat products, walk through TSA body scanners, and microwave food covered by cling film occasionally (GASP!). However, these are my own actions, undertaken at my own risk, and I would not advise others to make the same decisions just because I have accepted them as the right path for me.

rgconner's picture

Pity you can't find the old style ones, that were coated.

Got any friends that know how to powder coat? That stuff is indestructible and even comes in a clear base.


AnnieT's picture

Surely people were suggesting tossing the dough, NOT the dough hook? That's the way I read it, A.

Kitchen Barbarian's picture
Kitchen Barbarian

Yes, commercial bakeries use lots and lots and lots of aluminum pans, and some of them do put them through large commercial dishwashers - but the detergent they use is a specific formulation that is not reactive with metals such as silver or aluminum.

This is the same stuff we used to use at home, 40 and 50 years ago, but modern dishwasher detergents are formulated differently.  Hence, way back then in the 60s and 70s, I could run our aluminum cookware through the dishwasher, no problem.  But today it ruins the surface.  It isn't just the discoloration that comes with time - it causes that powdery surface coating that rubs off on other things - such as your food.

You CAN buy this stuff and use it in your dishwasher at home - but only if you want to buy it in industrial quantities.

LindyD's picture
Mini Oven's picture
Mini Oven

steel wool pad... the kind with soap, grab a big rag for my lap, some thick rubber gloves and a shallow pan of water.  Then put on a good video or download a movie and polish the dough hook until I can see myself in it.  In the beginning, rub a lot and as it shows a shine, try to ease up on the pressure to polish. Dip ever so often into the water to wash off the foam and see how your efforts are coming along.  Rinse in clear hot water and dry.  

This can also be done with aluminum knife handles, garlic presses and other aluminum tools that found their way accidentally into the dishwasher.  It's the salts, heat and duration under water that dulls the surface.  If left in a water filled mixer bowl overnight, the hook might show the same reaction just not as aggressive.

Lumber lady's picture
Lumber lady

So I finish my baking and rinse out my equipment then run them through the dishwasher. The beater, bread hook and whisk come out tarnished and grey chalky marks are all over everything they touch. Does Kitchenaid not make items that can go in their own dishwashers? Do they really expect us to wash things by hand? Why should I have to buy new parts because I used my Kitchenaid dishwasher. Their customer product development department should get on this issue before I have to chose between my mixer and my dishwasher. 

Crescentroll's picture

Celesteu commented that after five yrs she had never had this problem. Well I had never had the problem for 18 years, got a new KA mixer to replace it, and now I have a ruined batch of crescent roll dough. The stainless steel mixing bowl, washed according to manual in KA dishwasher,deposited gray streaks all through dough.  I had used my old dough hook--whited-coated.  KA quality is NOT what it used to be.  That's the problem.

kerdtsieck's picture

Just got my new KA about a month ago. I have used it a few times, always hand wash it and today while making sugar cookie dough, when i scraped the bowl (with a rubber spatula) this dark gray color was all over the dough. The first thing I did was "google" this to see if its happened to anyone else and stumbled upon this site! I'm pissed i just spent $400 and a crappy mixer thats going to ruin my food! Calling KA Monday! I knew I should have gotten the glass bowl mixer. So BUMMED!

Hippytea's picture

Crescentroll's experience definitely suggests this is down to the bowl, not the hook. But why would a stainless bowl react like that? Stainless is extremely unreactive - that's its big advantage.

Have these problems all been with new mixers? Is it possible there's a transit coating on the bowl that's hard to remove on initial washing, and that's what's staining the dough?


But I can't imagine why you'd put a transit coating on stainless steel. It doesn't need that sort of protection.


My Kenwood has a stainless bowl (which goes in the dishwasher) and aluminium beaters (which don't). I've never seen anything like that. In fact the beaters are so small that even if the oxide did come off I can't imagine it causing big grey streaks. It's a puzzle.

Another though that springs to mind is lubricant seeping down from the mechanism. Is that possible? Mixer lubricants are food grade but I still wouldn't fancy eating them.



summerbakes's picture

Hi team.  When in doubt call Kitchen Aid. 

It's a sealant they put on the stainless steel bowl.  I asked if it was safe as I'm pregnant and have eaten a little of the gray matter unintentionally. :(  It's food safe. 

They recommending cleaning it out twice with 1 tablespoon cooking oil and 1 teaspoon salt using a scouring pad. 

I asked why they don't recommend that in the manual or put a disclaimer in the bowl......Rep said it's been brought up but they haven't made plans to make this common knowledge. 


Cook with confidence. 

RickNY's picture

Thank you summerbake.

I just got a new KitchenAid mixer and washed the bowl thoroughly, but when making my first batch of dough, noted a very distinct grey coloring to the dough.  No way I was going to eat that.  

Thanks for the tip of washing with the oil-salt mixture.  It took THREE cycles of heavy scouring with that mix to remove the residue completely.  Even though the bowl is now clean and ready to use, the lip on the top outside of the bowl still leaves a dark residue on a paper towel when rubbed.  This is on the outside, so not in contact with the food, but is still annoying.  Kitchen Aid should definitely insert a note with each new mixer to clean the bowl in this manner before the first use.  They do insert a small slip saying "Hand Wash", so having the "Before Using" instructions on a slip would be easy for them.  

I do have to agree with other comments as to "why do they coat a stainless steel bowl with this?"  Stainless is inert, and should not need such an aggressive coating.


estebangtz's picture

Absolutely! KitchenAid should make a note on this before the first use! Today my wife was finally able to use for the first time her new mixer and she was very disappointed about how her dough was turning grey-ish. After googling a little and following the steps and some extra help of Bar Keepers Friend cleanser and a half dozen of paper towels the bowl is not giving any grey color to the dough. Thanks for the help!

CrispyCrust's picture

Aluminum is pretty standard for quality mixers. Hobarts use them as do many other commercial and home use mixers. 

Yes, aluminum is also reactive. the black discoloration can be caused by galvanic corrosion.

Galvanic in which aluminum which typically has a anodic index of -.9 volts is corroded when placed in a electrolyte bath (detergent) with another metal such as stainless steel which acts as a cathode and the effect is accelerated by heating of the electrolyte.

Ok so why is this happening. Aluminum oxide is less reactive than bare aluminum. When detergent manufactures stopped using phosphates recently they have been struggling to find a balance of cleaning power and too corrosive. Beyond removing grease, and suspending dirt and grime, phosphates balance pH, they prevent corrosion and hold calcium and magnesium in the water preventing spotting. Without phosphates, manufactures have turned to multipke other chemicals with various levels of efficiency ( and detrimental effects ) one of the issues is that detergents are more alkaline. Some may have pH values more than 9 (acids with pH less than 4 can have the same effect), strong enough to to remove the aluminum oxide coating exposing bare aluminum to other reactive processes and chemicals. Aluminum oxide is relatively resilient which is why mildwe hand washing soaps and detergents don't create the same problems.

Any way the short end of it is that the recent changes in detergent manufacturing is a cause for discoloration in the dishwasher. One effect that you seem to be describing is galvanic corrosion of bare aluminum.