A screwcap is a type of closure that is gaining increasing support as an alternative to cork. A screwcap is a metal cap that screws onto threads on the neck of a bottle. A plastic, cork, rubber, or other soft layer makes a seal with the mouth of the bottle.

Traditionally associated with extremely inexpensive jug wines or even "skid row" wines, the screwcap is making a comeback due to concern about cork taint. Screwcaps have a much lower failure rate than cork, and in theory will allow a wine to reach the customer in perfect condition, with a minimum of bottle variation. Cork, of course, has a centuries-old tradition behind it, and there are also concerns about the impact of screwcaps on the aging of wines that require decades to be at their best. Some argue that the slow ingress of oxygen plays a vital role in aging a wine, while others argue that this amount is almost zero in a sound cork and that any admitted oxygen is harmful. Various studies are underway, although one data point is that producers in Champagne have aged their wines under crown cap for quite some time with no apparent outcry. This is a debate that will take quite a while to settle. However, given that most wine is consumed within a year of production, there seems to be little justification on the basis of quality for using cork over screwcap.

Screwcap adoption in fine wines is proceeding in fits and starts. In July 2000, a group of producers of Clare Valley Rieslings bottled a portion of their wines in screwcap, and earlier that year Plumpjack announced it would bottle half its production of US$130 1997 Reserve Cabernet Sauvignon in screwcap. Other announcements have followed, including one from Bonny Doon Vineyards in July 2002 that 80,000 cases of its "Big House" red and white wine would be in screwcap. As of May 2003 no major, million case brand has gone to screwcaps.