Thick soy sauce is a sweet, syrupy, dark soy sauce commonly used in Chinese and Southeast Asian cooking. It is made by simmering regular soy sauce with sugar and sometimes a starch thickener, which gives it a glossy, molasses-like consistency. This homemade version is perfect for stir-fries, marinades, and dipping sauces, and it comes together in under 15 minutes with ingredients you likely already have.
Ingredients
- 1 cup (240 ml) regular soy sauce (use low-sodium if you prefer less salt)
- 1/2 cup (100 g) brown sugar, packed (or palm sugar for a more authentic flavor)
- 1/4 cup (60 ml) water
- 2 tablespoons (30 ml) molasses (optional, for deeper color and richness)
- 1 tablespoon (8 g) cornstarch (for thickening; omit if you prefer a thinner syrup)
- 1 teaspoon (5 ml) rice vinegar (optional, to balance sweetness)
Instructions
- In a small saucepan, combine the soy sauce, brown sugar, water, and molasses (if using). Stir over medium heat until the sugar dissolves completely.
- If using cornstarch, whisk it with 2 tablespoons (30 ml) of cold water in a small bowl to make a slurry. Set aside.
- Bring the soy sauce mixture to a gentle simmer, then reduce heat to low. If using the cornstarch slurry, slowly pour it in while stirring constantly. Continue to simmer for 2–3 minutes, until the sauce thickens to a syrupy consistency. It will thicken more as it cools.
- Remove from heat and stir in the rice vinegar (if using). Let the sauce cool completely before transferring to a jar or bottle.
- Store in the refrigerator in an airtight container. Use within 1 month.
Tips
- Substitutions: If you don’t have molasses, use dark brown sugar or add a teaspoon of honey. For a gluten-free version, use tamari or coconut aminos instead of soy sauce.
- Consistency: The sauce will thicken as it cools. If it becomes too thick, thin it with a little water or soy sauce. If it’s too thin, simmer it a bit longer.
- Storage: Always keep thick soy sauce refrigerated. It can solidify slightly when cold, so let it come to room temperature or warm it gently before use.
- Common mistake: Don’t boil the sauce vigorously after adding the cornstarch, as it can become lumpy. Keep the heat low and stir constantly.
Serving Suggestions
Use thick soy sauce as a glaze for roasted meats, a stir-fry sauce for vegetables and noodles, or a dipping sauce for dumplings, spring rolls, or grilled meats. It also works well as a marinade base for chicken, pork, or tofu—just add garlic and ginger for extra flavor.
Variations
- Spicy: Add 1–2 teaspoons of chili flakes or a chopped fresh chili while simmering.
- Garlicky: Add 2–3 minced garlic cloves to the sauce before simmering; strain them out if you prefer a smooth sauce.
- Thicker: Increase the cornstarch to 2 tablespoons (16 g) for a very thick, jam-like consistency.
- Sweet: Increase the brown sugar to 3/4 cup (150 g) for a sweeter sauce, similar to Indonesian kecap manis.
Storage and Reheating
Store thick soy sauce in an airtight glass jar or bottle in the refrigerator for up to 1 month. Because it contains sugar and soy sauce, it does not spoil quickly, but refrigeration helps maintain flavor and prevents fermentation. To reheat, warm gently in a saucepan over low heat or microwave in 10-second bursts, stirring between intervals. Do not boil, as it can burn. If the sauce thickens too much after refrigeration, whisk in a teaspoon of water at a time until it reaches the desired consistency.
Frequently Asked Questions
Can I use this in place of dark soy sauce in recipes? Yes, but note that thick soy sauce is sweeter and thicker. Use it in smaller amounts or adjust the sugar in the recipe.
Why is my sauce too salty? If you used regular soy sauce, it will be saltier than commercial thick soy sauce. Use low-sodium soy sauce or reduce the amount of soy sauce and increase water.
Can I make it without cornstarch? Absolutely. Simmer the sauce longer (about 10–15 minutes) to reduce and thicken naturally. It will be slightly thinner but still syrupy.
Is this the same as kecap manis? No, kecap manis is an Indonesian sweet soy sauce made with palm sugar and star anise. This recipe is simpler and more Chinese-style. For a closer kecap manis, add a star anise and a piece of galangal or ginger while simmering.
How long does it last at room temperature? It is best to refrigerate it. If left at room temperature, it should be used within a few days, but refrigeration is safer and extends shelf life.
Can I double the recipe? Yes, this recipe scales easily. Just ensure you have a large enough pot and store the extra in a separate jar.
Related
- Onion Powder to Fresh Onion: Substitution Guide
- Essen Recipes Cabbage: Hearty German-Style Dishes
- Even Almond Flour Recipes: Sweet & Savory Ideas
More recipes to cook
Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes
Spotted an error? Tell us and we will correct it (corrections policy).