Packaging Most wines are sold in glass bottles and sealed with corks (50% of which come from Portugal). An increasing number of wine producers have been using alternative closures such as screwcaps and synthetic plastic "corks". Although alternative closures are less expensive and prevent cork taint, they have been blamed for such problems as excessive reduction. Some wines are packaged in thick plastic bags within corrugated fiberboard boxes, and are called "box wines", or "cask wine". Tucked inside the package is a tap affixed to the bag in box, or bladder, that is later extended by the consumer for serving the contents. Box wine can stay acceptably fresh for up to a month after opening because the bladder collapses as wine is dispensed, limiting contact with air and, thus, slowing the rate of oxidation. In contrast, bottled wine oxidizes more rapidly after opening because of the increasing ratio of air to wine as the contents are dispensed; it can degrade considerably in a few days. Canned wine is one of the fastest-growing forms of alternative wine packaging on the market. Environmental considerations of wine packaging reveal the benefits and drawbacks of both bottled and box wines. The glass used to make bottles is a nontoxic, naturally occurring substance that is completely recyclable, whereas the plastics used for box-wine containers are typically much less environmentally friendly. However, wine-bottle manufacturers have been cited for Clean Air Act violations. A New York Times editorial suggested that box wine, being lighter in package weight, has a reduced carbon footprint from its distribution; however, box-wine plastics, even though possibly recyclable, can be more labor-intensive (and therefore expensive) to process than glass bottles. In addition, while a wine box is recyclable, its plastic bladder most likely is not. Some people are drawn to canned wine due to its portability and recyclable packaging. Some wine is sold in stainless steel kegs and is referred to as wine on tap. Storage Wine cellars, or wine rooms, if they are above-ground, are places designed specifically for the storage and aging of wine. Fine restaurants and some private homes have wine cellars. In an active wine cellar, temperature and humidity are maintained by a climate-control system. Passive wine cellars are not climate-controlled, and so must be carefully located. Because wine is a natural, perishable food product, all types—including red, white, sparkling, and fortified—can spoil when exposed to heat, light, vibration