By the time that Europeans arrived in what is now California there were roughly 300,000 indigenous people living in the region in both villages and seasonal gathering sites, and speaking over 60 different languages. When the Spanish first began to chronicle their observations of the flora and fauna they noted that the locals seemed to enjoy a rather wide-ranging diet that took full advantage of the regions extraordinary biodiversity.
Among the foods eaten commomnly by the Chumash, whose villages were around modern-day Santa Barbara, the Costanoans who lived along the Central Coast, the Ohlone who had villages on either side of the Bay, and the Miwok, who lived both along the north coast and in the Sierra foothils were: acorns, pine nuts, cherries, berries, grapes, honey, nuts, sprouts, roots, grasshoppers, birds eggs, snails, trout, salmon, shellfish. deer, elk, bear, ground squirrels, woodrats and waterfowl.
Each local group had its own favorite dish.The Pomo people, for instance, who lived in the Russian River Valley area, dined on roasted moth caterpillars accompanied bu salty sea palm. The Miwok, who lived in the foothills would collect clover in the spring, seeds in the summer, bulbs and mushrooms in the winter, and a variety of flowers and fruits throughout the warmer months.
If there was one staple food eaten throughout the entirety of what is now California it was acorns. Unlike today, oaks once ranged widely throughout the coastal hills making acorns abundant and easy to harvest. They were, however, also notoriously difficult to prepare.
Untreated acorns contain powerful astringents and toxins that demand a long leaching process to make them edible. The earliest solutions to this dilemma involved burying the acorns in a sandy ditch along with grass, charcoal and ashes. Later, the acorns would be soaked in fresh water, then pounded until they were sweet and edible.
The Pomo had a still more sophisticated method of acorn preparation. Interestingly it was almost identical to the one employed by early Sardinians half a world away. They would first ground the acorns into a fine meal, then mixed it with clay. After drying and then rinsing away the clay, they would mold the moist detoxified meal into flat cakes and bake them in an earthen oven.