"It ranges from 'Great idea! I love it!' to ... 'Get a life!' " said Rick Young, the recent University of California-Berkeley law school grad behind the measure.

The new law would make it a crime punishable by up to six months in jail and a $100 fine to sell brewed coffee that isn't certified as Fair Trade, organic or shade-grown. It would not apply to dry whole or ground beans.

Fair Trade coffee means farmers have received at least a minimum price set by the Fair Trade Labeling Organization. The price is $1.26 per pound and $1.41 for organic Fair Trade coffee, said Kenya Lewis of TransFair USA, an Oakland-based nonprofit that certifies all Fair Trade products in the United States.

Fair Trade farmers also have direct access to American markets. Coffee prices have dropped to levels below the cost of production and some producers who have to deal with middlemen are getting as little as 20 cents a pound, Lewis said.

Different groups certify coffee as organic or shade-grown — which means grown under trees that provide bird habitat and protect the soil. About 85 percent of Fair Trade coffee is organic and a higher percentage is shade-grown, Lewis said.

Estimates on the price impact of the Berkeley measure vary from nothing to pennies a cup.

Berkeley cafe owner Daryl Ross already carries Fair Trade brews as an option, but "we just don't support the idea that we should be forced to carry that as the only brand of coffee."

At City Hall, Mayor Shirley Dean supports a rule requiring the city to buy only Fair Trade coffee, but is wary of the idea of imposing that on private businesses.

"Who's going to enforce this?" she asked. "I can't believe anybody would be sent to jail for that."

Starbucks Coffee Co., which has three outlets in Berkeley, responded to the measure with a statement saying it helps farmers by signing long-term contracts and buying directly from farms and cooperatives.