AMERICAN CANYON -- There are now two manufacturers of screw caps for wine bottles planning to start making caps in Napa Valley.

Alcan Packaging, a division of Rio Tinto Alcan of France, recently declared it wants to start producing its Stelvin line of wine screw caps at its facility in American Canyon sometime this year. Currently the caps are made in Canada.

The stated goal is to add onto the current Alcan Packaging Capsules of California facility at 5425 Broadway in American Canyon. That operation currently distributes Stelvin caps in the North Coast and makes capsules that go over the screw tops. So far, the company hasn’t filed any applications for the project with American Canyon, according to the city planning department.

Alcan’s Stelvin cap has a long aluminum skirt that mimics the look of a traditional capsule-and-cork combination. However, continuing interest in such a closure that also does away with the tell-tale ribbed look of screw caps led to the launch last year of the Lux and Lux+ versions with smooth sides and better seals.

Alcan claims the Stelvin cap has half the market for wine screw caps in the U.S. Unlike New Zealand and Australia, where a majority of wine is capped, less than 10 percent of U.S. wine is capped versus corked. Some vintners with large-volume brands have predicted that share will climb to 50 percent in a decade.

Meanwhile, St. Helena-based equipment distributor Krueger Winery Technology and German beverage screw cap manufacturer Mala Verschluss-Systeme GmbH are working toward setting up a cap plant for Mala in south Napa by early next year.

The cap fabrication equipment to be installed in Napa is on order or being designed by Mala subsidiaries in Europe, and the company is planning the training program for local employees, according to Ortwin Krueger.

The companies are looking for 10,000 square feet of industrial space to set up the plant with possible room for expansion by an equal amount within two years. The intent is to settle on a location by fall. Even before that happens, Mala has started shipments of caps from German factories directly to North Coast wineries in cargo-container quantities.

"Smaller orders require us to break down containers and drop-ship caps to local wineries,” Mr. Krueger said.

Another major American producer of wine screw caps used by North Coast and California wineries is the Gallo family’s G3 Enterprises in Modesto.