To a very large pot add your olive oil and heat for 30 seconds before adding your onion, whole garlic, carrot and celery. On medium heat cook down the vegetable for around 20 minutes or until reduced by around half in size. Be sure to stir every so often to avoid burning.
Once the mixture is reduced by around half add the dehydrated mushrooms, Kombu and Miso to the pot and stir till everything is well coated. Cook for one minute before adding in your thyme, parsley, cilantro and black peppercorns. Stir for another minute and increase heat to high.
To the pot, add your 15 cups of water and bring to a boil. Using a wooden spoon scrape the bottom bits of the pan to make sure anything stuck at the base incorporates into the broth (this is where all the flavour lives). Once your mixture has come to boil, reduce heat and simmer for around 40-50 minutes or until reduced by around half.
Let the broth cool slightly before putting through a mesh sieve to strain into another pot or into jars. Lightly press down on the veggies to release any excess liquid. Don't press too hard, you want this to remain clear with no lumps.
Great on it's own, in soups + stews. Before sure to season with salt before eating!
Notes
Cool and freeze your veg to use again or compost.Be sure to use Kombu, white miso and dehydrated mushrooms - these 3 ingredients are so important and will really, really elevate your brothUse good quality (or even organic) produce and herbsUse filtered water (save yourself time by pre-boiling)10000% use a strainer to press out any excess liquid from the veg, this makes for an incredibly saturated taste + ensures you end up with a smooth stock