Tears of Llorona is an extra extra añejo tequila. It begins as 100% blue agaves from high volcanic slopes in Jalisco, where growth is slow. Master Tequilero Germán Gonzalez hand selects the agaves and has them harvested late, increasing their starch and sugars. The piñas are roasted slowly in the traditional way. His yeast is proprietary and fermentation is slow. Distillation is by copper pot still and barreling is at very high specific gravity.
Tears is aged in three different barrels -- oak that has previously held scotch, sherry, and brandy -- and brought together in very small batches to create a complex fusion that is more like a cognac than a tequila. Germán then bottles at 43% specific gravity to balance the flavors. This results in a very high rate of osmotic loss - the “angel's tears” that are one reason for the name, Tears of Llorona.
More detail than that remains a proprietary secret known only to Germán himself