In a warehouse south of downtown Paso Robles, California, Stewart McLennan is serving wine straight from the barrel, his voice echoing across the concrete floors as he pours a generous splash of cabernet.

The atmosphere isn’t what you’d find among the oak-shaded vineyards and elegant tasting rooms more typical of California’s central coast. But it’s here, in an industrial zone called Tin City, that some of the area’s most intriguing, often experimental, wines are being created by ultra-small-batch producers.

Down by the train tracks, McLennan’s winery produces a line called Golden Triangle, with cab franc, syrah, and cabernet grapes sourced from vineyards on Paso Robles’ westside.

I rarely turn down a glass of red, but I’m no wine expert. Even so, the tastes McLennan serves me are diverse and exciting, far from the typical tasting-room fare.

Paso is a town with a pioneer spirit, so it’s not surprising that independent, renegade winemakers are flourishing here. Most, like McLennan, offer tastings by appointment, but if you’d like to see what’s being produced in warehouses and small family-owned vineyards across the region, more than 50 tiny wineries will unite for the annual Garagiste Festival, from November 5-7, which McLennan co-founded five years ago.

Ryan Pease from winery Paix Sur Terre will be pouring his line of mourvèdre at this year’s event, and he says the festival is unique in bringing together “people who have built things from the ground up,” whether they’re making wine on the side while working a full-time job or are professionals using top-notch facilities.

Garagiste is a French term originally used in Bordeaux to describe independent winemakers working in garages or other rustic facilities. Paso’s garagistes aren’t really working in their garages, but all are very small (producing fewer than 1,500 cases a year) and many are breaking away from industry traditions.

Some experiment with unusual techniques, like whole-stem inclusion or extended macerations. Others produce “blends you wouldn’t normally find and that aren’t permitted,” McLennan says, like the unorthodox 2010 Deno Grenache-Zinfandel blend that will be served at the festival’s opening-night winemaker dinner – a wine McLennan assures me is “awesome.”