In a temperature-controlled basement below Estela, chef Ignacio Mattos keeps mason jars of fermenting fish collars, buckets of koji inoculating on rice, and shelves of aging condiments that won't be ready for months. When we visited, sous chef Rebecca Kim was tending to a batch of shrimp paste that had been sitting in salt and humidity for six weeks. "People think fermentation is passive," she explained, turning the mixture with a wooden spoon. "It requires constant attention." The Invisible Infrastructure Mattos introduced serious fermentation to Estela around five years ago after visiting Japan. Now nearly 40% of the restaurant's flavor comes from fermented elements. The team makes their own miso using chickpeas instead of soybeans, ages fish bones in koji to create umami-rich bases, and develops house-made hot sauces that take months to mature. Each batch is labeled with fermentation start dates and projected finish dates. A single plate of pasta might contain four different fermented elements, none of which appear on the menu—they're simply the foundation of how we taste. The commitment requires space, patience, and accepting that some experiments fail. Mattos estimates that roughly 15% of their fermentation projects never reach the dining room. For him, that failure rate validates the entire operation. "If we're not pushing into unknown territory, we're not learning anything new."