Place the dried chiles in a bowl and cover with hot water. Let them soak for 15 minutes, until softened.
4 dried guajillo chiles, 2 dried ancho chiles
While the chiles soak, add the cumin, coriander, oregano, black peppercorns, kosher salt, and annatto seeds to a spice grinder, or high powered blender, or mortar and pestle. Grind until fine. If using achiote paste, skip this step and just add it to the blender later.
1 tablespoon cumin seeds, 1 tablespoon coriander seeds, 1 teaspoon black peppercorns, 1 tablespoon annatto seeds, 1 tablespoon dried Mexican oregano, 1 tablespoon kosher salt
Drain the soaked chiles and add them to a blender along with the chipotles, garlic, ground spices,, salt, pineapple juice, vinegar, and oil. Blend until smooth. Add a splash of water or more pineapple juice if needed to loosen it up.
1-3 chipotles in adobo, 6-8 garlic cloves, ¾ cup pineapple juice, ¼ cup apple cider vinegar, ¼ cup neutral oil
Give it a taste; it should be tangy, smoky, a little sweet, and well-seasoned. Add more salt or chipotle peppers, if needed. Let it sit for 10 minutes before using to let the flavors settle.