MARTINEZ -- Grapes are moving over for hops, and craft beer festivals are becoming a popular mainstay of city events, like the upcoming Bay Area Craft Beer Festival in Martinez.

"Art and wine festivals were fine in the 90s, but people want something different," said sponsor Jason Petros of Martinez-based craft beer radio company The Brewing Network. "With craft beer, there are a lot of complex flavors. More and more craft beer is bridging that gap between wine drinking and beer drinking."

Leanne Peterson, executive director of festival producer Main Street Martinez, said beer festivals are definitely gaining in popularity.

On Saturday, more than 30 microbreweries will offer tastings at the fourth Bay Area Craft Beer Festival at Martinez Waterfront Park.

Many of the breweries represented are Brewer Association World Beer Cup 2012 gold-, silver- or bronze-medal winners from Alameda and Contra Costa counties where new microbreweries are sprouting annually.

Sponsor brewers include Martinez' own Creek Monkey Tap House pouring Rude Boy Red; and Concord's Ale Industries' brewers Steve Lopas and Morgan Cox who, in December, released their first edition label Golden State of Mind for their renamed flagship brew, Orange Kush.

The label, now featuring a pair of snowshoes on a pristine winter scene, will change with the seasons.

Some other breweries pouring are well-established E.J. Phair Brewing Company of Concord; Heretic Brewing Co. out of Pittsburg; and Altamont Beer Works, whose longtime Livermore residents and owners Stephen Sartori and Gregory Robles boast, "We are Livermore's first brewery since Prohibition."

Calicraft Brewing Co., launched in May 2012 by veteran home brewer and Walnut Creek family man Blaine Landberg, will be there as will Schubros Brewery from San Ramon.

San Francisco's Amendment Brewery, Triple Voodoo and others will be lined up alongside North Bay brewers, including Lost Coast Brewery from Humboldt, Lagunitas Brewing Company from Petaluma, and Lucky Hand Brewing Company of Novato.

The festival draws up to 2,000 visitors, many of whom live on the west side of the Caldecott Tunnel. Peterson said organizers want to make it easy for them to get to Martinez, so there is again a free shuttle from the North Concord BART station.

The shuttle leaves North Concord BART beginning at 11 a.m. and loops by the festival's official hotel, the John Muir Inn, to downtown every half-hour. The last one leaves downtown at 7 p.m.

Accompanying the pours will be live music provided by the classic rock band Lumberyard, and Petty Theft band, the American classic and contemporary tribute to Tom Petty and the Heartbreakers.

Food from local restaurants will also be available, Peterson said.

She noted that a portion of the proceeds from the event benefit the Martinez Rotary and Foster a Dream and encourages residents to check out the East Bay Craft Beer Festival.

"Have an open mind and discover new tastes and friends. Craft beer producers and enthusiasts are a fun loving, happy group."

if you go
What: Bay Area Craft Beer Festival
When: Noon to 4 p.m. Saturday, April 20
Where: Martinez Waterfront Park, North Court Street
Cost: $35 pre-sale online, Les Schwab Tires, 3800 Alhambra Ave., Martinez; and Ale Industries, 975 Detroit Ave., Concord; or $45 at gate. Includes unlimited tasting and commemorative glass. No one under 21 allowed; I.D. required
Information: Main Street Martinez 925-228-3577