A special and increasingly popular type of closure (screw cap, twist or ROPP = Roll On Pilfer Proof Closure) for wine bottles as an alternative to the cork (natural cork) made from oak bark. These are made of non-corrosive metal (mostly aluminium alloy) with an inner sealing layer of polyethylene (PE), PVDC (polyvinylidene chloride) or tin foil. In the beverage industry, this is also called MCA closure (MCA = metal closure aluminium). The emotional discussion as to whether this involves a "loss of culture" is countered by the relatively inexpensive production and the fact that it can avoid the problem of cork taint with natural corks. In addition, the often used pro-argument for the "pop" when enjoying wine as a sensual pleasure is not valid, because a bottle should be opened professionally as silently as possible (applies especially to sparkling wine).