Baked Goods
How long does powdered sugar last?
Powdered sugar keeps indefinitely in the pantry by USDA’s reckoning, 18–24 months opened for best quality — seal it tight, because the cornstarch in it soaks up cabinet smells.
Pantry, opened
How long does it keep?
| Pantry | Indefinitely |
|---|---|
| Pantry, opened | 18–24 months |
- Pantry: Sugar never spoils, but for best quality use within 2 years of opening.
Can it sit out?
Powdered sugar is shelf-stable, so sitting out at room temperature isn’t the safety question — storage time is.
How to tell if powdered sugar has gone bad
- Grey or spotted patches where damp got into the bag
- A flat, cardboard-y smell when the bag opens
- Moths or webbing anywhere in the container
When in doubt, throw it out.
Sift before it goes anywhere near a glaze — those lumps are trapped moisture and they won’t whisk out.
Quick answers
How long does powdered sugar last?
Powdered sugar keeps indefinitely in the pantry by USDA’s reckoning, 18–24 months opened for best quality — seal it tight, because the cornstarch in it soaks up cabinet smells.
How long can powdered sugar sit out?
Sitting out at room temperature isn’t the safety question for powdered sugar — storage time is.