You need just four ingredients to make French lean breads: flour, water, salt, and yeast. Simple, right? That’s why we recommend lean breads as a good starting place for new bakers. The baguette is not only a loaf by which many bakers are measured, it is also the quintessential example of French lean bread. Although the word “baguette” has a number of meanings (including a stick or concertmaster’s baton), surly its most common meaning is this long, slender loaf. One of its distinctions is the crispy crust achieved by incorporating steam in the baking process.
The master French Lean Bread recipe from Modernist Bread is made with commercial yeast rather than levain. We use commercial yeast to make a preferment called a poolish, which imparts a slightly tangy flavor and a nice finished appearance to the bread. The dough is versatile enough to work when formed into boules, bâtards, baguettes, and other shapes. The best examples of French lean breads have a crusty exterior, a light yellow–beige crumb that yields to the teeth, a mild flavor that goes with nearly everything, and an aroma that will make you want to inhale deeply through your nose.
-Adapted from Modernist Bread