ELK GROVE, Calif.—Rather than build their own bottling plants, many of California’s small wineries depend on about two-dozen mobile bottling operations.

The machines can churn out about 50 corked, capped and labeled bottles a minute, saving vintners time, money and headaches.

Mike Wackman, owner of McConnell Estates Winery in Elk Grove, got into the wine business five years ago when he dug out a cellar beneath his house and installed a grape crusher, fermentation tanks and oak barrels.

Spending another $300,000 on an automated bottling line didn’t make sense for the 2,500 cases he produces each year, so he turned to mobile bottlers. About half of California’s 2,275 wineries produce less than 5,000 cases a year.

The mobile bottling machines can cost $500,000 to $1 million but serve dozens of vintners.