What is the primary ingredient in the batter for French pancakes or crepes?

The primary ingredient in the batter for French pancakes, or crepes, is milk. The batter typically consists of a mixture of milk, flour, eggs, and sometimes a little sugar and salt. Milk is essential because it not only contributes to the liquid content of the batter, allowing the ingredients to combine smoothly, but it also adds richness and flavor.

In crepe preparation, the milk helps achieve the desired thin and delicate texture that characterizes crepes. It hydrates the flour, enabling the gluten to develop to the right extent for a tender crepe that can hold fillings without breaking apart. While butter, water, and yeast can have roles in various types of batters or doughs, they are not the primary components for crepes, which rely on milk for both consistency and taste.