In a large stockpot, bring the vegetable stock to a boil. Add the ginger, lime leaves, cilantro, bay leaves, garlic, chile, and fish sauce, then remove from the heat and let steep, uncovered, for 30 minutes.

Using an extra-fine-mesh strainer or chinois, strain the stock into an airtight container or containers.

Discard the solids. Use immediately or let the stock cool to room temperature, cover tightly, and refrigerate for up to 5 days or freeze for up to 3 months.