Un estudio muestra que la harina cambia el sabor de la masa madre

Anyone who bakes sourdough bread knows that no two loaves are exactly alike. The loaves may seem very similar, and only someone with a deep understanding of their bread's flavor would notice. Temperature, hydration, and fermentation times all play a role, and now research has added another easily measurable element: the flour.

The study, published in the scientific journal Microbiology Spectrum, was conducted by researchers at North Carolina State University. Its aim was to understand how the type of flour and the frequency of flour turnover influence the sourdough microbiome, that is, the community of yeasts and bacteria that determine its fermentation and sensory characteristics.

In the laboratory, eighteen starter cultures were created using three types of soft wheat flour: type 00 flour, whole wheat flour, and an unspecified bread flour. Each type fed six cultures, half of which were renewed daily and the other half every two days, for twenty-eight days. Using DNA sequencing techniques, the researchers tracked the evolution of the microbial communities over time.

The results were consistent with the yeasts: regardless of the type of flour or the amount of yeast, the genus Kazachstania was predominant in the mature cultures. This confirms what has been observed in other studies, in which a few species tend to stabilize and dominate fermentation.

With lactic acid bacteria, however, the type of flour significantly influenced the species composition. Wholemeal flour increased the presence of Companilactobacillus; bread flour, Levilactobacillus; and 00 flour, where Lactiplantibacillus and Furfurilactobacillus predominated. These genera are known for their role in the production of organic acids and aromatic compounds, well-established aspects that carry more scientific than gustatory weight.

The study did not include a direct sensory evaluation of the bread, which is a real shame. The researchers point out, however, that each bacterial community is associated with different levels of acidity and specific aromatic metabolites. Changing the flour used in the dough can promote different microbial balances and, therefore, distinct flavor nuances.

The frequency of renewal, however, had a limited impact: when comparing daily feeding with feeding every other day, no significant differences were found in the final composition of the communities. Under controlled conditions, at least during the observed period, the choice of flour had a much greater impact.

It's worth remembering that the experiment was conducted in a laboratory, which minimizes variables such as utensils, the baker's hands, or airborne microbes. In a home or professional kitchen, these factors can indeed influence microbial diversity. Even so, the trend remains: the way the sourdough starter is fed affects the final flavor of the product.