Chad Yakobson, the founder and director of the Crooked Stave Artisan Brewing Project, ages his beer in barrels and massive oak wood foedres crammed into a small industrial park on the outskirts of Denver. From the outside, it feels more like a storage unit – and this being Denver, the brewery's neighbors are marijuana grow rooms. The humble location is at odds with the sophistication of Yakobson's operation, which grew out of his graduate-level work studying Brettanomyces (wild beer yeast) fermentations in Edinburgh, Scotland. Yakobson brings scientific rigor to each batch of Crooked Stave beer, which he refers to as a "prototype." Surrette, named after the French word for tart, is probably the most approachable wild yeast beer we've ever tasted. Yakobson calls it a "provision saison" because it is slightly higher in alcohol than most saisons and aged two to 18 months before it's readied for drinking.

Surrette is composed of four different grains in addition to malted barley, wheat, rye, spelt, and oats. The body holds up well and the flavor is rustic, earthy, and just slightly tart, thanks to aging in large French oak foudres with Brett and Lactobacillus, another souring agent. While Brett is notorious for imparting an often off-putting, horse-blanket barnyard flavor and aroma, Surrette is remarkably clean tasting and easy drinking.