Skip the store-bought version and make your own homemade shrimp stock using shrimp shells and heads, mirepoix, garlic, and dried herbs. This recipe is courtesy of Emeril Lagasse.
Place shrimp shells and heads in a large colander and rinse under cold running water.
Place all ingredients in a heavy 6-quart stockpot. Add 4 quarts water, and bring to a boil over medium-high heat, skimming surface occasionally. Reduce heat to medium-low and simmer, uncovered, for 45 minutes, continuing to skim surface occasionally.
Remove stock from heat and strain through a fine-mesh sieve set over a large bowl; let cool completely. Refrigerate stock up to 3 days or freeze in an airtight container, up to 2 months.