Cut the whole celery head into 3-inch pieces from root to leaves and add to the stockpot.
Quarter the carrots and onions, leaving the skins on for added flavor and color. Trim only the root end of the onion, then add everything to the pot.
Slice the garlic head in half widthwise (no peeling necessary) and add both halves.
Add herbs, bay leaves, and whole peppercorns directly to the pot.
Pour in 1 gallon of water.
Bring to a boil, then reduce heat and simmer on low to medium-low for 1 hour.
Remove large vegetable pieces before straining the remaining liquid through a mesh strainer.
Carefully pour the hot stock into mason jars and secure lids.
Let it rest on the counter for about 2 hours until room temperature. Retighten lids and refrigerate.
Notes
Storage: Refrigerate sealed jars for up to 2 months. Once opened, use within 2 weeks. Freeze in airtight containers for up to 3 months, or in a water bath can for longer pantry storage.Whole Veggies = More Flavor: Leave the skins and outer layers on (when appropriate) to build deeper flavor and more nutrients into your stock.Salt Is Optional: Add salt if you know how you’ll use the stock, or leave it unsalted to control seasoning later.