There is no straightforward answer. The production of aluminum takes a serious toll on the environment as it is sourced from bauxite, an ore that contains a high concentration of aluminum. Harvesting the aluminum component generates two materials: one is aluminum oxide, which is a fine white powder, and the other is a thick, red sludge containing caustic soda. This sludge has no practical application. Likewise, the destruction of land caused by aluminum production, i.e., the land that is displaced (often permanently) during the course of bauxite mining, is detrimental to the environmental. Manufacturing a disposable plastic bottle from new materials, transporting it and disposing of it in a landfill has a smaller environmental impact than a disposable aluminum can made from new material. The key word here is, however, disposable. Recycling aluminum takes only 5% of the energy required to create a new aluminum can for the first time. So there are a number of factors to consider before we can answer the question.
Metal is a good packaging choice in that it retains its value and is generally suitable for recycling.There are a number of advantages to recycling metal. For example, some types of metal can be recycled over and over again. The State Alcohol & Tobacco Company of Iceland recently released a comprehensive report on the lifetime impact of various forms of packaging for alcohol, and the conclusion was that it is best to buy beer in cans and wine in cartons and boxes.