Combine all ingredients, except water, in the instant pot.
Pour water in until it fills just below the max line. About 10 cups will be enough.
Place lid on instant pot, seal, set manual pressure to high for 45 minutes. Once finished, do a full natural release.
Allow the stock to cool slightly and use a spoon to skim off any fat that accumulates at the top. Strain stock. Adjust seasoning with salt and pepper if needed. Store in containers to use immediately or freeze.
