How to Use Starches as a Thickening Agent

When starches are used as a thickening agent you always need to make a slurry then pour it into the hot mixture. (examples include: cooked cream pies, puddings, sauces, gravy, soups)

How to make a slurry

  • Stir together starch with water. The recipe will give you the ratio. Mix until there are no lumps. (always use room temperature, never warm or hot) After the slurry is mixed it is ready to pour into the hot liquid.
  • To prevent lumping, it is important to be stirring the hot mixture while pouring in the slurry. So be prepared to stir and continue stirring until the mixture comes to a boil and cooks briefly. ((When you pour in the slurry the mixture will turn white and cloudy. As the mixture cooks it will thicken and turn opaque).

How much starch per cup of liquid

  • 1 Tbsp starch per cup of liquid will give a thin to medium consistency. As a reference a thin sauce would be similar to the consistency of a salad dressing. (see Italian dressing below)
  • 2 Tbsp per cup of liquid will give a gravy like consistency.
  • 4 Tbsp per cup of liquid will give a cream pie consistency.

Other recipes made with a starch slurry:

Common Starches and What to Use


  • Is a great thickener, if you don’t want to freeze it. Sauces made with cornstarch will turn spongy when thawed.
  • Needs to come to full boil.
  • Thickening power breaks down when cooking acidic fruit sauces like lemons, oranges and pineapple.

Arrowroot Powder

  • Arrowroot powder also goes under the name of arrowroot flour.
  • Arrowroot powder is the most neutral flavor of all the starches.
  • It thickens quickly, once mixture has thickened and cooked briefly, remove it from its heat source. Over cooked arrowroot powder will break down and go watery.
  • Works well acidic liquids.
  • Is freezer friendly.

Tapioca Starch

  • Known for glossy sheen in Asian cooking/stir-fry’s.
  • Loses it thickening power when thickening an acidic liquid.
  • Tapioca starch is heat stable for a long time while arrowroot powder will break down when overcooked.
  • Is freezer friendly.