By Fred Decker

Cornstarch and agar -- the first conjures images of thickened sauces and soups, wheres the latter sounds more like a lab chemical than a common cooking ingredient. Both are carbohydrate-based food products used to thicken liquids. Cornstarch is used primarily for sauces and custards, or applications that result in soft gels. Agar, a gelling agent refined from seaweed, is used more often to create solid gels like those made from gelatin. However, both thickeners are plant-based and vegetarian friendly, and you can easily substitute cornstarch for agar in any liquid you want to thicken.

how to substitute agar flaes with cornstarch
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how to substitute agar flaes with cornstarch

Step 1

Measure 2 tablespoons of cornstarch for each 1 tablespoon of agar flakes called for in the recipe. If you're not following a recipe, measure 1 tablespoon of cornstarch for every cup of liquid you want to thicken.

Step 2

Prepare the recipe and heat the liquid you want to thicken to a simmer. Whisk the cornstarch into an equal amount of cold water or stock.

Step 3

Slowly add the cornstarch slurry, using a whisk or spoon to incorporate. The liquid should thicken almost immediately.

Step 4

Add more cornstarch slurry if necessary to create the desired consistency. The liquid will thicken as it cools, so it may not be necessary.