What makes rye bread hollow?

Sourdough Fermentation: Rye bread is often made using sourdough fermentation, which involves the use of wild yeast and bacteria. During fermentation, sourdough produces gases that form air pockets within the dough. If these air pockets are not adequately distributed or if the dough is not kneaded and shaped properly, it can lead to a hollow loaf of bread.

High Hydration: Rye flour has a high water absorption capacity compared to other flours. If too much water is added to the dough, it can result in a loose and weak gluten structure, leading to bread with voids and gaps. Maintaining the proper hydration level for rye bread is crucial to achieve a consistent and well-structured loaf.

Low Gluten Content: Rye flour contains less gluten compared to wheat flour. Gluten is responsible for providing structure and strength to bread dough. The weaker gluten structure in rye bread may not be able to effectively hold gas bubbles, resulting in holes and cavities within the bread.

Over-proofing: Proofing refers to the stage when the dough is allowed to rise before baking. Over-proofing can cause excessive fermentation, leading to the breakdown of the gluten structure. This makes the dough weak and prone to collapsing, which can result in a hollow loaf.

Incorrect Baking Conditions: The temperature and steam management during baking play a significant role in the final texture of rye bread. If the oven temperature is too low or if there's insufficient steam, the dough may not rise properly and the surface can crust prematurely, trapping the gases inside and creating gaps.

By carefully monitoring fermentation times, hydration levels, shaping techniques, and baking conditions, it is possible to produce rye bread with a balanced fermentation and a desired crumb structure.