A number of years ago, I stopped buying broth. Instead, after an excellent tip from a co-worker (thanks, Mark!), we started saving all our veggie scraps and popping them in a bag in the freezer. Onion tops, pepper cores, hard tomato parts, squash skins, corn cobs, tough stems and everybody in between eventually makes it into the one-gallon freezer bags that my husband lovingly calls “gross bags.” To transform it all into stock, I simply dump a full bag’s contents into a pot, fill it with water and let it boil itself into brothy goodness for a couple of hours. (Don’t worry, husband has an excellent and equally loving name for the final product: garbage tea.)
Part of the excitement of making broth this way is that it never turns out the same twice. While that once meant matzo ball soup that had a hint of ginger and cilantro, the broth usually blends in well with whatever soup I’m making, while also ensuring that the flavors are wonderfully complex. Plus, in contrast to store-bought broth, I have complete control over the sodium content of the eventual soup.
Kitchen Scrap Broth
Onion scraps. Onion tops, white bottoms of green onions. I think onion is the one critical scrap to have for making a good broth. Others advise also including carrot and celery scraps, but I've never found them essential.
All other veggie scraps. Peels, skins, cores, tough stems, cobs. There’s some debate on whether to add potentially overpowering cruciferous veggies like broccoli, cabbage and Brussels sprouts. I’ve added small amounts of them in the past and never found them to add too much intense flavor.
DO NOT INCLUDE: Anything moldy or rotten, or green potato peels or potato sprouts, which contain a toxin.
Bones. If you’re not making a vegetarian broth, add chicken bones and the like.
1. Designate a one-gallon freezer bag as your “gross bag” (no offense taken if you don’t want to use my husband’s appealing moniker).
2. Keep the bag in the freezer and add scraps to it as you generate them during meal prep. We find it takes a month or two to build up a full freezer bag. Once the bag is full (or, whenever you’re getting ready to make soup), pour the contents of the bag into a pot and fill it with water.
3. Bring the water to a boil, and then let it simmer for at least two hours. For a richer broth, consider adding even more veggies (I know we sometimes find ourselves with two “gross bags” ready for use). Your house will smell cozy!
4. After several hours, or after you’ve determined you’ve gotten all you can out of the veggies, strain the mixture into a bowl. Enjoy the broth and make sure to compost the remains of the veggies.