Agar agar is a gelling agent derived from seaweed used mainly in vegan recipes to replace gelatin.
It’s fairly easy to find now, but if you don’t have it on hand for a recipe, there are a few alternatives.
The best alternatives at this point are xantham gum and guar gum. You can substitute these in a 1:1 ratio (e.g. 1 tbsp of either gum for 1 tbsp of agar agar). It won’t give you quite the same “jelly” texture as agar agar, but will thicken up your food.
Another decent substitute is carrageenan, however that’s even harder to find, so it’s rarely an option.
If you’re desperate, there’s 1 final option: starch. Either corn starch or tapioca starch can do in a pinch.
It’s a bit more time consuming of a substitution though.
How to Substitute Corn or Tapioca Starch for Agar Agar
Start with a 2:1 ratio, so 2 tbsp of corn or tapioca starch for each tbsp of agar agar flakes or powder.
Then, mix it with water in a 1:1 ratio. For example, 2 tbsp of corn starch should be whisked together with 2 tbsp of water. Then add it to your recipe.
If your recipe isn’t thickening up enough, add more starch to it.