LOCAL.FRESH.CRAFT BEER. Opened in December 2015, Black Doubt Brewing is the first true nano-brewery in Mammoth Lakes, CA. Black Doubt brews all of its beers by hand, 100 gallons at a time, in the same tasting room where you'll be enjoying its creations. Stop by for a round of tasters, a few pints or to fill up your growler! Guests are welcome to bring in their own food. Black Doubt is located across the street from the Vons shopping center.