|Saturday mornings in the southern part of the city - amidst a maze of freeways, live chickens in a stupor, and competitive, full-contact roller derby among elderly Chinese-American women (just without the roller skates) - is Alemany Farmers' Market time. This ain't no yuppie Ferry Building farmers' market; this is where the locals get down and dirty to compete for fresh fruits and vegetables at a discount. It mellows out more in the late mornings, but come early and you had better bring your game face and your knee pads: few area events can match the Hobbesian fight club required to purchase the morning's bok choy before it's picked over. Further away from the mainstage m�l�e are the prepared food vendors, including this Walnut Creek-based caterer that runs a cart service specializing in South American food. They offer Argentine alfajores and are the only option at the market for espresso. Using a single-group Astra machine and Equator Estate beans, they pull shots with absolutely no crema. However, the shot is full-bodied and carries a bit of flavor: mostly a mellow spice and some earthiness. Not a bad cup, but the espresso they make doesn't differ much from filter coffee. At which point you're better off getting something from a French press at the nearby Ritual Roasters tent/kiosk.