Low FODMAP Oyster Sauce

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Traditional oyster sauce contains shellfish and garlic, both of which are high FODMAP. This version uses dried shiitake mushroom powder and soy sauce to recreate that deep, umami flavor without any IBS triggers. Coconut sugar adds a hint of sweetness while cornstarch gives the sauce a thick, glossy finish. It’s easy to make in 15 minutes and stores well for quick, flavorful meals.

Ingredients Needed:

Mushroom Powder:

• 1 cup dried shiitake mushrooms: ground into powder (you’ll only use 2 tsp)

Sauce Base:

• 1 cup (240 ml) water: base of the sauce
• ¾ cup (135 g) coconut sugar or white sugar: adds natural sweetness
• ½ cup (120 ml) soy sauce: use gluten-free tamari for gluten-sensitive
• 2 tsp mushroom powder: rich umami flavor
• 1 tsp salt: balances taste
• 2 tbsp (15 g) cornstarch: thickens the sauce

How To Make Low FODMAP Oyster Sauce:

Make Mushroom Powder:
Blend 1 cup dried shiitake mushrooms in a high-speed blender for 30–45 seconds until finely ground. Store extra in an airtight jar.

Make the Sauce:
In a saucepan, whisk together 1 cup water, sugar, soy sauce, 2 teaspoons of mushroom powder, salt, and cornstarch until smooth.

Cook and Thicken:
Place saucepan over medium heat. Bring to a simmer, whisking regularly for 5–7 minutes until the sauce thickens to a glossy texture.

Cool and Store:
Remove from heat. Let cool for 10–15 minutes. Pour into a jar and refrigerate.

Recipe Tips:

• Only use 2 teaspoons of the mushroom powder—save the rest
• Use gluten-free soy sauce (tamari) for a fully gluten-free version
• Coconut sugar adds richness, but white sugar works just as well
• For extra umami, add a drop of sesame oil when using the sauce
• Always stir before using—it thickens slightly in the fridge

How to Store & Reheat:

• Room Temperature: Not recommended
• Fridge: Store in a sealed jar for up to 2 weeks
• Freezer: Can be frozen in small portions for up to 3 months

Nutrition Facts (approx. per 1 tbsp):

• Calories: 26
• Sodium: 370 mg
• Protein: 0.4 g
• Fat: 0 g
• Carbs: 6.5 g
• Fibre: 0.2 g
• Sugar: 5 g

FAQs

Is oyster sauce low FODMAP?
Regular oyster sauce is not, due to garlic, onions, and oyster extract. This version is shellfish-free and made with FODMAP-safe ingredients.

What can I use instead of mushroom powder?
You can use Monash-tested oyster mushroom powder if available, or omit it for a lighter flavor, but shiitake powder adds the best umami.

Can I make this sauce gluten-free?
Yes—just use gluten-free tamari instead of regular soy sauce.

How do I use this oyster sauce alternative?
Use it in stir-fries, marinades, fried rice, or as a dipping sauce—just like traditional oyster sauce.

How long does it last in the fridge?
Up to 2 weeks when stored in an airtight jar. Stir before using.

Try More Recipes:

• Low FODMAP Miso Soup
• Low FODMAP Pickled Beets
• Low FODMAP English Muffins