There are several variations in artisanal raicilla production. Some use the fire-pit (horno); others use an above-ground oven. Some producers use only a single distillation; others distill twice; some use clay, others use copper. Trimming is done with unusual care to avoid off-flavors from the spines. Mexicat’s José Salcedo, a third- generation distiller uses an igloo-shaped clay oven. A batch is 3.5 tons.  Salcedo builds a big fire inside and lets it burn until the wall of the oven is very hot. He then rakes out the embers and seals the agaves inside for 2 days.  Fermentation is by wild yeasts in 200-liter tinas and takes 5-8 days.  Salcedo double-distills in a copper-lined pot.