Agar Agar vs Cornstarch - Substitutes and Differences
Learn the differences between agar agar and cornstarch, and discover the best substitutes for each. Understand when to use agar agar vs cornstarch in your recipes.
Quick Answer
Agar agar creates firm gels while cornstarch only thickens. Use 1 teaspoon agar agar powder per cup for gelling, or 2 tablespoons cornstarch per cup for thickening. For agar agar substitutes, use gelatin (1:1) or pectin (1:1). For cornstarch substitutes, use arrowroot (1:1) or tapioca starch (1:1).
Best Substitutes
Gelatin
1:1 for agar agarAnimal-based gelling agent with identical properties to agar agar
Best for:
Not suitable for vegans, but provides identical gelling to agar agar
Pectin
1:1 for agar agarPlant-based gelling agent, good for fruit-based recipes
Best for:
Works best with acidic ingredients and sugar
Arrowroot Powder
1:1 for cornstarchStarch-based thickener with similar properties to cornstarch
Best for:
Creates clearer sauces than cornstarch, good for gluten-free recipes
Tapioca Starch
1:1 for cornstarchStarch-based thickener with similar thickening properties
Best for:
Creates glossy, clear sauces, good for fruit fillings
Potato Starch
1:1 for cornstarchStarch-based thickener with similar properties to cornstarch
Best for:
Good for high-temperature cooking, doesn't break down easily
Xanthan Gum
1/4:1 for cornstarchFermentation-derived thickener, very potent
Best for:
Use sparingly as it's very potent, provides smooth thickening
Carrageenan
1:1 for agar agarSeaweed-derived gelling agent with similar properties to agar agar
Best for:
Excellent vegan alternative with similar gelling properties
Cooking Tips
- 💡Agar agar creates firm gels while cornstarch only thickens liquids
- 💡Use agar agar when you need sliceable, firm textures (jellies, panna cotta)
- 💡Use cornstarch when you need smooth thickening (sauces, gravies, puddings)
- 💡Agar agar needs to be boiled for 1-2 minutes to activate
- 💡Cornstarch should be mixed with cold liquid before adding to hot liquids
- 💡Agar agar sets at room temperature, cornstarch thickens when heated
- 💡For clear sauces, use arrowroot or tapioca starch instead of cornstarch
- 💡Agar agar can be reheated and reset multiple times
- 💡Cornstarch breaks down with prolonged cooking or high heat
- 💡Both agar agar and cornstarch are flavorless and won't affect taste
Frequently Asked Questions
What's the difference between agar agar and cornstarch?
Agar agar is a gelling agent that creates firm, sliceable gels, while cornstarch is a thickener that only makes liquids thicker. Agar agar is used for jellies and desserts, while cornstarch is used for sauces and gravies.
Can I use cornstarch instead of agar agar?
No, cornstarch cannot replace agar agar for gelling applications. Cornstarch only thickens liquids but doesn't create firm gels. For agar agar substitutes, use gelatin, pectin, or carrageenan instead.
Can I use agar agar instead of cornstarch?
Agar agar can provide some thickening, but it's not ideal for sauce thickening as it creates gels rather than smooth, pourable textures. For cornstarch substitutes, use arrowroot, tapioca starch, or potato starch.
Why does my cornstarch sauce get thin when reheated?
Cornstarch breaks down with prolonged cooking or high heat, causing sauces to thin out. For sauces that need to be reheated, use arrowroot powder or tapioca starch instead, as they're more heat-stable.
Can I make jelly with cornstarch?
No, cornstarch cannot create firm gels like agar agar or gelatin. It will only thicken the liquid but won't create sliceable jelly. For jellies, use agar agar, gelatin, or pectin instead.
Summary
Learn the differences between agar agar and cornstarch, and discover the best substitutes for each. Understand when to use agar agar vs cornstarch in your recipes.