In a glass measuring cup, crumble the saffron threads into the fish stock and let stand for 10 minutes.

In a large pot, heat the olive oil. Add the minced garlic and diced onion and cook over moderately high heat, stirring, until the vegetables are softened, about 4 minutes. Stir in the flour until incorporated. Add the saffron-infused fish stock and Albarino and bring to a simmer, stirring, until thickened. Add the clams, cover and cook, shaking the pot, until the clams open, about 6 minutes. Discard any clams that do not open. Spoon the clams into bowls. Season the Albarino sauce with salt and pepper, pour it over the clams and serve them with crusty bread.