Question about Bosch 700 Watts MUM6622 Universal Series Stand Mixer

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Bosch aluminum dough hook has black coating

Just recently my Bosch aluminum dough hook had a black/grey substance start rubbing off of it. I have been washing it in the dishwasher and didn't know if that was causing some problem. Is it still safe to use?

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  • terylray Feb 16, 2008

    My Bosch is doing the same thing, but it is all the matte-colored grey metal parts. They are leaving grey smudges that are rubbing off on my hands. Also, there are small white bumps or dots appearing on the metal surface. I need to know if this is safe for my family to continue to eat from.

  • Anonymous Aug 23, 2008

    Yes, I am also having the same problem. The black substance is getting in my dough. Can you please make and all stainless steel dough hook.

  • shmelvik
    shmelvik Oct 10, 2012

    The dough hook is supposed to be cleaned by hand. The manual states not to wash it in a dishwasher. Maybe, that's the main issue?



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Aluminum tends to oxide when its washed under harsh dishwasher detergents. I use Palmolive oxi dish soup (blue bottle) just by trial and error. Put some on a sponge/ (non-mettal) scouring pad, and scrub the attachment, it will take off the majority of the grey gunk thats rubbing off and after a few times of cleaning it, it'll get back to its aluminum luster. Easy remedy to clean your dough hook -- or any other aluminum item.

Posted on Sep 19, 2009


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The problem is where the pin on the beater shaft locks into the hook may be wearing down or the hook itself.when you put the hook on see if you get alot of play in the hook (wiggle it and if it feels really loose its worn).its still safe to use but eventually (and this may be quite sometime) the pin may break off the beater would then have to replace the pin and hook.

Posted on Jan 28, 2008


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