Rescuing a lumpy sauce
Starch granules swell and turn gluey in hot liquid. Drop in flour or cornstarch dry and the outside of each clump gels at once, sealing a core of dry powder inside. That is a lump.
Prevent lumps or strain them out
Mix cornstarch with cold water to make a slurry, or cook flour in fat for a roux, so grains are separated before they meet heat. If lumps have formed, whisk hard, buzz with an immersion blender, or pour through a sieve.
Test yourself
Questions from the interactive lesson, with the answer and the why.
You sprinkle flour straight into hot gravy and get lumps. Why?
The outside of each clump gelled and sealed the dry flour inside. Gelled starch forms a skin around the dry center.
True or false: A blender or strainer can fix a lumpy sauce even after lumps form.
True. A strainer or blender breaks or catches lumps even after they form.
What went wrong? You sprinkle dry flour onto a simmering gravy and stir gently. Lumps appear.
The flour went in dry, so the clumps gelled outside. Separate the grains first with fat or cold water.
Fill the blank: A lump is dry starch wrapped in a ___ skin.
A lump is dry starch wrapped in a gel skin. Wet starch swells into a gel that seals the clump.
The gravy is already lumpy. What fixes it?
Pour it through a sieve or blend it. Both remove or break up the clumps.