From classic to unconventional, seasonal sour beers offer a year-round discovery.

Sour beers can surprise – you don’t know how sour, fruity, bubbly or refreshing they may be until you try them – especially if you aren’t a connoisseur. At Alvarado Street Brewery, instead of brewing a typical sour beer, they produce mixed fermentation sour ales (under their Yeast of Eden program), or quick-brewing sours, called kettle sours.

The brewery produces different sours every few weeks, making as few as five barrels (in Carmel) or 40-60 barrels (in Monterey), and they sell out fast. “They go very, very fast. Most of our beers don’t last more than a week,” says Wade Caswell, head brewer at Alvarado Street Brewery & Grill.

As this issue went to print, the only sour on tap is Sonic Palate, a barrel-aged saison with kiwi, which Caswell says is unique among the brewery’s offerings. “It’s got a lot more complexity to it – very, very tart and it’s a lot more effervescent,” he says. Yeast of Eden sour beers like this spend anywhere from six months to two years in a barrel.

Sours under their Alvarado Street label are generally more fruity, such as Howzit Punch, which includes passionfruit, orange and guava; or Biggie’s Blueberry Brunch Bonanza with blueberries and vanilla beans. These beers also tend to offer “a creamy, sweeter mouthfeel,” Caswell adds.

The brewery’s two locations release new beers each Friday – the lineup, sours included – is announced via social media.

Alvarado Street Brewery is located at 426 Alvarado St. Monterey, 655-2337; and at Carmel Plaza, Suite 112, Mission and 7th, Carmel, 293-8621. asb.beer