All About Cornstarch
Your complete guide to cornstarch - discover how to store it properly, identify when it's gone bad, and find the best substitutes for your recipes.
How Long Does Cornstarch Last?
Storage times and freshness tips for cornstarch in different conditions.
Safety first: This guide provides general information. When in doubt, throw it out! Trust your senses and err on the side of caution. If something smells, looks, or tastes off, don't consume it.
Unopened Pantry2-3 years past best-by date (or indefinitely if stored perfectly)
Signs of Spoilage
Punctured or damaged packaging, visible signs of pests (small holes, insect activity), significant hard clumping due to moisture ingress, off-odor if stored near strong smells.
How to Check
Visually inspect the packaging for any tears, holes, or signs of tampering. Check for any movement or dark specks inside the package, indicating pests. Gently squeeze the package to feel for hard, unyielding clumps that cannot be broken apart. A slight, clean starchy smell is normal; any strong or 'off' smell is a concern.
Storage Tips
Store in a cool, dark, dry place, such as a pantry or cupboard, away from direct sunlight, heat sources, and areas prone to humidity. Keep it away from strongly scented items like spices, coffee, or cleaning products, as cornstarch can absorb odors.
Opened Pantry1-2 years after opening (for optimal quality)
Signs of Spoilage
Hard, unmixable clumps that don't break apart easily (indicating significant moisture absorption), discoloration (yellowish, grayish, or brownish tint), presence of pests (tiny insects, larvae, webbing), musty, sour, or 'off' odor, visible mold (rare, but possible if heavily exposed to moisture).
How to Check
-
Visual Inspection: Look for a smooth, fine, bright white powder. Any discoloration, dark specks, or fuzzy patches are signs of spoilage.
-
Touch Test: Feel the texture. It should be silky and powdery. Hard, unyielding clumps are a bad sign. If clumps are soft and break apart easily, it might still be okay, but quality could be diminished.
-
Smell Test: It should be virtually odorless or have a very faint, clean starchy smell. A musty, sour, chemical, or otherwise 'off' smell indicates it has gone bad.
-
Small Taste Test (if visual and smell pass): Take a tiny pinch. It should be bland and starchy. Any off-taste means discard.
Storage Tips
Immediately transfer opened cornstarch to an airtight container (glass, plastic, or metal) to protect it from moisture, pests, and odor absorption. Ensure the container is completely dry before adding the cornstarch. Store in a cool, dry, dark place. While cornstarch doesn't 'spoil' in the sense of becoming unsafe quickly, its thickening power and texture can degrade over time, affecting recipe results.