Researchers have uncovered a simple yet elegant mechanism behind ancient wine production. By drying grapes and soaking them in water, early winemakers could reliably ferment sugars into alcohol. The study suggests that natural sun-drying transformed the raisins’ micro-habitat, making it friendlier to alcohol-producing yeasts like Saccharomyces cerevisiae. This process, known as “raisin-seeded fermentation,” has been confirmed through microbial sequencing and experimentation.
The team found that all three sun-dried samples fermented successfully, while only one incubator-dried bottle and two combination-dried bottles completed fermentation. Microbial analysis revealed a decrease in overall species diversity during fermentation, with S. cerevisiae dominating the process. The study’s findings provide insight into how ancient people achieved fermentation without isolating yeasts.
The researchers note that commercial raisins treated with edible oil to prevent clumping may not be suitable for spontaneous fermentation. However, naturally sun-dried raisins without coatings can still produce wine through this process. Future studies aim to refine the understanding of this natural fermentation mechanism and its potential applications in food production and waste reduction.
Source: https://www.earth.com/news/ancient-winemakers-used-a-surprising-ingredient-and-it-wasnt-grapes