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What Is Aluminum Foil Made

2016-10-27

Aluminum foil is made entirely of aluminum. It is essentially aluminum ingots that are squished between beefy rollers. The thinner you want the foil, the tighter the rollers squish it.

Aluminum replaced tin for foil largely after WWII. Tin did the same sort of thing but left food with a bit of an aftertaste, so production switched to aluminum. Sometimes you still hear people call it "tin foil" for that reason.

Technically, a lubricant is sprayed on the foil to keep it flat, but generally it burns off. In some types of aluminum foil (for specific industrial uses) not all the oil is burned off, but I don't think you would call this an "ingredient" in aluminum foil because it is not always there and is in a minute quantity.

Scientists are exploring whether over-exposure to aluminium may be posing threats to human health. For instance, high concentrations of aluminium have been detected in the brain tissue of patients with Alzheimer’s disease. Scientists have examined the community of old people with Alzheimer’s and concluded that it is a modern disease that’s developed from altered living conditions associated with society’s industrialisation. These conditions may include high levels of aluminium in daily life.

Aluminium poses other health risks, too. Studies have suggested that high aluminium intake may be harmful to some patients with bone diseases or renal impairment. It also reduces the growth rate of human brain cells.

The ingots of aluminium are heated to make them more malleable, rolled, passing backwards and forwards through large rollers as the slab gets thinner and thinner, and longer and longer. This metal strip is hot rolled to a thickness of 2 to 4 mm (2000 to 4000 microns) and then coiled, before being cold rolled to metal thicknesses of between 6 and 400 microns. The thinnest foil used for wrapping chocolates may be only 6 microns thick (about one-eighth the thickness of newspaper!), with household wrapping and cooking foil between 11 and 18 microns, lidding foil between about 30 and 40 microns, and foil for foil containers generally between 40 and 90 microns.