Aluminum is very soft, in order to increase the hardness of the addition of a small amount of manganese and other metals into the aluminum alloy. Aluminum is easy to oxidize at normal temperature, aluminum oxide is basically harmless to people, that is, as long as there is an oxide layer will be safe.
But if it comes in contact with an acidic liquid, it erodes the oxide layer and causes the aluminum to come into direct contact with the liquid.
In terms of chemical properties, aluminium and aluminium alloy do not have big distinction, so if use it to hold water, and the oxidation layer that does not use hard content to destroy inner wall can use basically safety.Do not store drinking water in aluminium kettles for too long and do not spend the night.
By the way, the Aluminum Kettle Spout, Aluminum kettle lids are also same theory.