I have a new grain mill that I am hesitant to use because the rollers are anodized aluminum. As I understand it the anodized aluminum is actually aluminum oxide and supposedly non-toxic. I realize that the aluminum/alzheimer connection is in doubt (but I have seen it fluctuate as so many "certainties" do). I do not wish to take a chance playing with aluminum in my food, so can you answer the following questions:

Given that eventually the aluminum oxide would wear off, exposing me to the aluminum. Would the aluminum form a new protective oxide and if so, how fast would the aluminum re-oxidize and reform a protective barrier? (instantaneously, days, weeks?)

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    $\begingroup$ Pretty much instantaneously. On the other hand, very little food has a hardness exceeding alumina, so the wear will be minimal. $\endgroup$
    – Jon Custer
    Oct 24, 2018 at 17:07

1 Answer 1


I am not an expert in food safety, so understand this is for information only.

Aluminum, when exposed to the atmosphere, will immediately oxidize. Aluminum oxide is not very soluble an will likely pass straight out of the body when ingested. Aluminum oxide is in certain toothpastes as an abrasive.

If aluminum is exposed to fluoride, chloride, or sulfate there could be an issue if it converts to a soluble form. As long as grinders are cleaned according to the manufacturer's recommendations this should not be an issue.

The amount of aluminum oxide which wears off a grinder is related to the abrasiveness of the material being ground. Stainless steel wears about six times less than aluminum. A titanium grinder is even better.


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