Wild Fermentation
Wild fermentation uses the microbes already present — on skins of fruit, in the air, on hands and surfaces — rather than adding commercial cultures. The winemaker who relies on indigenous yeasts. The baker who catches wild yeast for sourdough. The fermentations that predate microbiology and still work.
Sandor Katz became the evangelist of this approach. His books, Wild Fermentation (2003) and The Art of Fermentation (2012), argued that fermentation doesn’t require labs or packets of freeze-dried cultures. Cabbage becomes sauerkraut through lactobacilli already on its leaves. The craft is creating conditions where the desired microbes thrive.
The mechanism is selective pressure. Salt inhibits most bacteria but Lactobacillus tolerates it. Submerge vegetables in brine and lactobacilli dominate. They produce lactic acid, lowering pH further, selecting for acid-tolerant strains. Each stage creates conditions for the next. The environment shapes the population.
Wild fermentation produces variability. Batch-to-batch differences in microbial populations create batch-to-batch differences in flavor. Commercial operations hate this. Artisans embrace it. The Lambic beers of Belgium use wild yeasts and bacteria from the Senne Valley air — each brewery’s fermentation profile is literally unreproducible elsewhere.
The risks are real. Without controlled inoculation, undesirable microbes can dominate. Kahm yeast creates a white film. Molds can produce mycotoxins. Botulism is rare but possible in low-acid anaerobic environments. Traditional ferments evolved safety through practice — the saltiness of sauerkraut, the acidity of pickles, the alcohol in wine all protect against pathogens.
Commercial culture packets are insurance. They flood the substrate with desired organisms before wild populations establish. The result is predictable but homogenized. Every packet of bread yeast is the same strain: Saccharomyces cerevisiae, domesticated for millennia, now propagated in industrial quantities.
Wild fermentation advocates argue that microbiome diversity matters — for flavor, for gut health, for maintaining cultures that industrial food erodes. The argument echoes concerns about agricultural monocultures. When every fermentation uses the same strains, we lose the microbial diversity that traditional practices maintained.
Whether this matters depends on what you value. If you want consistent product, commercial cultures win. If you want the particular taste of your kitchen, your climate, your hands — wild fermentation is the only option.
Related: [[fermentation]], [[terroir]], [[starter-cultures]], [[swales]]