During the first stage of lambic fermentation, which organisms are dominant?

In the first stage of lambic fermentation, the dominant organisms are indeed Kloekera apiculata and enterobacter. Lambics are unique to the Brussels region of Belgium and are traditionally fermented using spontaneous fermentation, which involves exposing wort to the open air for natural inoculation.

During this initial phase, various wild yeasts and bacteria present in the environment begin to colonize the wort. Kloekera apiculata, a type of wild yeast, is typically among the first organisms to thrive. Enterobacter species, which are bacteria that can contribute to mixed fermentation profiles, also play a significant role during this stage. These microbes help prepare the wort for later fermentation stages where more yeasts, such as Saccharomyces, become prominent.

This process distinguishes lambic fermentation from traditional brewing methods where brewers yeast is introduced directly and dominates from the start. The initial dominance of Kloekera and enterobacter allows for a complex interplay of flavors, leading to the characteristic profile of lambic beers. Over time, as fermentation progresses, other strains of wild yeast, including various Saccharomyces strains, will also become significant in the fermentation process, but they do not dominate at the very beginning.