Ancho vs Guajillo
The two pillars of a dried-chile base, and they do opposite jobs. Ancho (1,000–2,000 SHU) brings dark, smoky-sweet depth; guajillo (2,500–5,000 SHU) brings tangy brightness and red color. Don't choose — use both. A two-to-one ancho-to-guajillo paste is a reliable starting point for chili and adobo.