Aluminum

The question people arrive with is Alzheimer's, and the honest answer is that the link has not held up. It began with a 1965 experiment in which aluminum injected into rabbit brains produced protein tangles, later shown to be biologically different from the tangles of Alzheimer's disease. ATSDR's position is that we do not know for certain whether aluminum causes Alzheimer's disease; Germany's BfR says a connection is unlikely on current evidence; Alzheimer's Research UK concludes there is not enough high-quality evidence to say everyday exposure causes it. Nobody has shown cookware to be the mechanism, and ATSDR states plainly that very little aluminum enters the body from aluminum cooking utensils. The real, duller issue is cumulative dietary load: EFSA's tolerable weekly intake is 1 mg per kg of body weight, roughly 10 mg a day for a 70 kg adult, and ATSDR puts typical US dietary aluminum at 7-9 mg a day, so most people sit near the limit before cookware is involved. That is why BfR advises against uncoated aluminum foil, trays, and pans for sour or salty foods such as tomatoes, rhubarb, and cheese: bare aluminum dissolves into acid and salt in a way that anodized or coated aluminum does not. People with impaired kidney function are the group that genuinely accumulates aluminum and should take that avoidance advice seriously.

Aluminum conducts heat far better than stainless steel, which is why it is the core of most clad pans and the body of most moka pots. It melts at 660C, well above any stovetop, but it is soft long before that: thin pans warp on a ripping-hot dry burner or in a thermal-shock quench, and an empty moka pot left on heat will discolor and can distort. Heat is also what takes the acid reaction above from slow to fast, which is why the warning is about hot acidic food rather than a cold tomato in foil. Dishwashers dull and darken bare aluminum; hand washing keeps it looking like metal.

Aluminum is conspicuously light for its size and non-magnetic - but so is 304 stainless, so a magnet alone only rules out plated or carbon steel. Weight is the better tell: an aluminum pot feels almost empty next to the same pot in steel. Bare aluminum develops a chalky grey oxide film that leaves grey marks on a dishcloth or your fingers; anodized aluminum is smooth, uniform, often dyed, and does not mark. If a spec sheet just says "aluminum", ask three things: bare, anodized, or coated; which alloy; and for any bottle or can, what the interior lining is. An "aluminum bottle" listing with no liner answer almost always means an epoxy-lined interior.

Soft enough to dent, scratch, and gouge. It will not rust but it does pit in salt, and bare aluminum darkens with use - scouring brings the shine back and the patina returns. Hand wash. A moka pot or camp pot treated this way lasts decades; the gasket and the handle usually fail long before the metal does.

This is aluminum's strongest card. It is one of the few materials that is genuinely and economically recycled rather than aspirationally recycled: scrap has real value, cans are accepted curbside almost everywhere, and remelting takes a fraction of the energy of smelting new metal. Foil is the exception - most programs reject it when it is soiled or balled up too small to sort.