With the rising popularity of craft beers and the explosion of microbreweries in California, a San Francisco brewer says he plans to open the state’s first craft malting facility — a move that could revive grower interest in barley, a crop that has seen downward trends in production for years. Compared to fruits, vegetables and nuts, barley is considered a minor crop in California, with most of it grown for animal feed. When grown as malting barley for brewing beer, the grain fetches a much higher price. But farmers have not had much reason to grow malting barley after the state’s last malt house closed years ago. Ron Silberstein, the head brewer at Thirsty Bear Brewing Co., says he wants to change that. His brewery-restaurant already buys much of its ingredients from local farms. Now he wants the barley used in making his beers to be locally grown, too. “I am certain that other (malt houses) will come along after — possibly before — us,” he said. California is home to more than 450 microbreweries, more than any other state, according to the California Craft Brewers Association. There are 27 craft malt houses in the U.S., but none in California.