Chorizo vs chouriço: the Iberian sausage divide
Iberian Peninsula
Chorizo (Spanish) and chouriço (Portuguese) share the same Iberian origin — ground pork seasoned with pimentón and salt, stuffed into natural casings — but they are not the same product. Spanish chorizo is typically drier, more cured, and redder; Portuguese chouriço varies enormously by region in spice level, smoking technique, and texture. The word covers products ranging from the firm, brick-red chouriço de vinho (Alentejo, wine-cured) to the soft, heavily smoked chouriço preto of the north.
The use of pimentón is the defining shared characteristic: both are coloured and flavoured by sweet or sweet-hot dried red pepper. Neither uses anything equivalent to the cumin-heavy North African sausage merguez or the Mexican-American chorizo (which is a completely different product).