The American Association of Cereal Chemists (AACC) has done research on the development of gas cells in bread doughs during proofing. This caught my interest the same time I wanted to get bigger holes in my baguettes.
Many older papers by the AACC are available to the public, but only a few more recent ones. In an article with the catchy title “Quantitative Assessment of Gas Cell Development During Proofing of Dough by Magnetic Resonance Imaging and Image Analysis”(pdf-link) hole-size and -distribution in the crumb of baguettes are treated. The research group used a dough made with bread improvers, but since physical properties are discussed, the findings should apply to a “Baguette de tradition au naturel” as well. Here are some of the results the researchers have found to be true:
- Slow shaping of baguettes results in a more regular distribution (isotropy) of holes and higher overall volume.
- Fast (and consequently more vigorous) shaping of baguettes results in a more irregular distribution (anisotropy) of holes and a smaller overall volume. A small number of very big holes appear (see Fig. 4 A).
- “Stress lines” (barely visible lines of poorly risen dough portions in the crumb that often appear in spirals) must be destroyed to ensure a good aeration of the bread. But too much force will disrupt internal structures, in contrast to slow-deformation where they would stay intact.
- “[…] the crumb structure is already defined at the early stage of the breadmaking process, and baking is not the sole determining step.”
- Doughs kneaded at 26° will have a higher volume than those kneaded at 28°C.
Also mentioned is a result about frozen doughs:
- “It is known that frozen storage of dough can negatively affect the hydration state of the gluten component, and that leads to smaller volume after proofing and baking (Esselink et al 2003a). As a prepcaution, in the study the doughs were stored for short periods (two to three days), so changes in gluten hydration would be minimal.”
(Fast shaping (left) vs. Slow shaping (right), Source: http://www.aaccnet.org)
I took this to heart and will now make sure I shape the baguettes firmly (to destroy stress lines) but lightly in a moderately warm spot in the kitchen (to keep stress lines thin and low in number). And I also feel entitled to infer, that hand-shaped baguettes are of superior quality compared to those spit out by industrial moulders.
What I want in a baguette are rather large holes distributed throughout a dough with good aeration and high volume. This is best achieved by increasing dough hydration and letting time do its work. Of course, other factors are important as well: overall flavor and crispy crust with a toasty aroma and deep reddish brown color. I find that the inclusion of sourdough helps.