Instant Pot Vegetable Broth (Vegan)

Recipe from The Vegan Instant Pot Cookbook by Nisha Vora 
Husband-Tested in Alice’s Kitchen
Makes about 10 cups 

When you have veggie scraps on hand, you can make this to use for any recipe calling for vegetable broth.  I like to use fresh herbs, dried mushrooms, mushroom stems, dried chili peppers, carrot peels, carrot and celery tops and ends, peppercorns, etc… Making your own broth allows you to control the ingredients.  This is a pretty forgiving recipe.

1 Tablespoon olive oil (optional, use only if sautéing vegetables)
2 medium yellow onions, papery skin still on and roughly chopped
4 celery stalks, roughly chopped
3 large carrots, roughly chopped
1 cup sliced mushrooms
2-3 cups vegetable scraps
3 bay leaves
6 cloves garlic, skins on and smashed
1 ½ teaspoons whole black peppercorns
10-12 sprigs of fresh thyme
6-8 small sprigs of fresh rosemary
1 ½ teaspoons kosher salt
1 teaspoon ground turmeric (optional, it doesn’t affect the taste, but it will add antioxidants to the broth)
10 cups cold water

(This first step is optional, but it does seem to yield a richer, complex flavor. If you choose to skip the sautéing step, just add all the ingredients to the pot. You'll still have a fine broth.) 

*Select the Sauté setting on the Instant Pot.  After the pot heats up, add the oil and sauté the onions for about 8 minutes.  Add the celery and carrots and cook until they begin to soften, about 5 minutes.  Select the Cancel button. 
**Add the mushrooms, vegetable scraps, bay leaves, garlic, peppercorns, thyme, rosemary, salt and turmeric (if using) to the Instant Pot.  Add the water and stir to combine.  
Secure the lid and set the Pressure Release Valve to Sealing. 
Select Pressure Cook setting at High for 15 minutes.
Once the time is up, allow a Natural Release for another 15 minutes. Switch the Pressure Release Valve to Venting to release any remaining steam.
Open the pot and carefully strain the vegetable broth into a fine-mesh sieve over a large bowl (preferably with a spout/lip) and discard the solids.
Allow the broth to cool to room temperature.  Store in the refrigerator for 3-4 days or in the freezer for up to 3 months.