Vegetable Broth
Homemade vegetable broth without onion, garlic, or mushrooms.
Ingredients
- 12 cups (2.8 L) cold filtered water
- 3 medium carrots, roughly chopped
- 1 stalk celery, roughly chopped
- 1 medium parsnip (about 75g), roughly chopped
- Green tops of 1 large leek, rinsed and roughly chopped (about 1 cup)
- Green tops of 5 to 6 scallions, roughly chopped
- 1/2 corn cob, broken into a few pieces (optional, for sweetness)
- 6 sprigs fresh parsley
- 4 sprigs fresh thyme
- 1 sprig fresh rosemary
- 2 bay leaves
- 1 tsp whole black peppercorns
- 1 tbsp olive oil
- Salt, to taste (added after straining)
Instructions
Build the Pot
- Warm the olive oil in a large stockpot over medium heat. Add the carrots, celery, parsnip, leek greens, and scallion greens. Cook for 5 to 7 minutes, stirring, until the edges start to color. This step is optional but builds a deeper, sweeter base.
- Add the corn cob pieces, parsley, thyme, rosemary, bay leaves, and peppercorns.
- Pour in the cold water. It should cover everything by an inch or two. Do not add salt yet.
Simmer
- Bring to a gentle boil over medium-high heat, then drop to low.
- Hold at a bare simmer (small occasional bubbles, not a rolling boil) for 1.5 to 2 hours with the lid cracked. If it boils hard, the greens and herbs can taste bitter.
- If the water drops below the solids during the simmer, top it off with hot water.
Strain and Cool
- Turn off the heat and let the pot sit for 10 minutes so the solids settle.
- Pour through a fine-mesh sieve into a clean pot or large bowl. Don't press hard on the solids; let the broth drip for cleaner flavor. Discard the solids.
- For a clearer broth, strain a second time through cheesecloth.
- Salt to taste now that the volume is set.
- Cool quickly by setting the container in an ice bath or dividing into shallow containers. Refrigerate within 2 hours of cooking.
Tips & Substitutions
- Leek greens and scallion tops are the onion swap. Fructans are concentrated in the white bulb of both plants; the dark green tops are low-FODMAP and carry the onion flavor you want in a broth. Leek green tops are low-FODMAP up to 54g per serve, scallion greens up to 75g per serve.
- Skip most mushrooms. Common button, cremini, and portobello mushrooms are high in mannitol and can push a vegetable broth high-FODMAP quickly. Canned and oyster mushrooms are better tolerated in small serves (check the current Monash app for the specific type).
- Fennel fronds are a nice add. The wispy green fronds are low-FODMAP and add an anise note. Go easy on fennel bulb, which climbs in fructans at larger serves.
- Add garlic-infused olive oil at the end if you want a garlic note. Stir 1 to 2 teaspoons into the finished broth. Adding it to the simmering pot wastes the flavor.
- Save scraps in a freezer bag. Carrot tops and peelings, celery ends, leek green trim, parsnip peels, and corn cobs freeze well and build up quickly. A full gallon bag plus fresh herbs is enough for one pot.
- For a richer (non-vegan) broth, add a Parmesan rind during the simmer and remove before straining. Aged Parmesan is very low in lactose, so most people tolerate it well. Drop the "Vegan" label if you use this.
Why This Works
The store-bought broth trap. Swanson Vegetable Broth, Pacific Organic Vegetable Broth, and Imagine Organic Vegetable Broth all list onion, garlic, or both in their ingredient decks. Better Than Bouillon's vegetable base is the same story. A single cup can put a sensitive reader over the fructan threshold before the soup even starts.
Leek greens and scallion tops do the work. Fructans sit in the white bulb of alliums, not the green tops. The greens carry the aromatic volatile compounds that make broth taste like broth, without the fructan load.
Celery is fine at one stalk across a batch. Celery's FODMAP load is mannitol, and it climbs with serve size (a low-FODMAP serve is about 15g, roughly a quarter stalk). One stalk spread across 8 cups of broth keeps the per-bowl amount well under the Monash low-FODMAP threshold.
Homemade is the baseline. Because onion and garlic are in almost every commercial vegetable stock, a clean homemade pot is the only way to know exactly what's in the broth you're cooking with. Pair this with the low-FODMAP chicken broth for meat-based soups, and you have both sides of the stock shelf covered.
Storage
Refrigerate in sealed containers at 40°F (4°C) or below for 3 to 4 days. For longer storage, freeze in 2-cup portions for soups and stews, and in a silicone ice-cube tray (about 2 tablespoons per cube) for deglazing pans or finishing sauces. Frozen broth keeps for up to 3 months. Thaw overnight in the fridge, or add cubes straight to a hot pan.
Not sure about an ingredient? FODMAP Tracker includes a database of 1,000+ foods with FODMAP ratings to help you cook with confidence.
For educational purposes only. Not medical advice. Consult a healthcare professional for personal guidance.
References
- All about onion, garlic and infused oils on the Low FODMAP Diet — Monash University FODMAP Blog
- How to Use Spring Onion (Green Onion) on the Low FODMAP Diet — A Little Bit Yummy
- Are Leeks Low FODMAP? 2026 Guide — Gourmend Foods
- Low FODMAP Vegetable Stock — FODMAP Everyday
FODMAP Tracker