How long does flour last?
Unopened, it keeps in the pantry for about 12 months. Once opened, it keeps in the pantry for about 6 months.
Product: White all-purpose wheat flour.

Shelf life of flour at a glance
| Storage | Unopened | Opened |
|---|---|---|
| Pantry | 12 months | 6 months |
| Fridge | – | 12 months |
An airtight container in a cool, dry spot protects it from moisture and pantry pests. Whole-wheat flour goes rancid sooner because of its oil, after about 3 to 6 months.
Does flour go bad?
Food past its date has not necessarily gone bad. The times on this page are guideline values for food stored properly. In the US, date labels are not required by federal law (infant formula is the exception), and most of them describe quality, not safety. A "Best if Used By" date is not an expiration date, and many products are still fine after it. A "Sell By" date is meant for the store, not for you. Look at the food and smell it before you taste a little. Mold, an off smell or a bulging can or lid means it goes in the trash. Take a "Use By" date on perishables such as meat, fish, deli meats and dairy seriously: eat or freeze them by that date.