Most health officials agree that cooking with aluminum poses no significant health risks and beer brewed in aluminum kettles does not absorb enough of the metal to be harmful.
For context, an antacid tablet contains about 200 mg of aluminum – significantly less than what is absorbed by beer brewed using aluminum kettles.
Aluminum-linked dementia, however, has been found in elderly dialysis patients when the dialysis fluid is contaminated with aluminum. Dialysis doesn’t efficiently remove aluminum from the body.
In a study published in Environmental Sciences Europe, it was found that higher heat does result in more aluminum being absorbed into the contents of the kettle.
Uncoated aluminum kettles will react with the contents being cooked in them. Oxidizing prevents your wort from developing any off-flavors due to interaction with the metal.
To oxidize your new aluminum brew kettle, fill it with water, cover it with a lid and boil for about 60 minutes. Pour the water out and let it dry, or wipe it with a soft cloth.
The main issue with using aluminum pots and kettles in brewing is the inability to use harsh chemicals or scrubbers to clean them. The oxidized coating on the kettles may make it difficult to tell if they are clean.