Is it a bad idea to keep cut open onion in the fridge?

It is not advisable to keep cut-open onions in the refrigerator. Here's why:

1. Spoilage: Cut onions are more prone to spoilage as they are exposed to air, moisture, and various microorganisms. The cut surface provides an easy entry point for bacteria and fungi to grow, leading to faster deterioration.

2. Flavor Loss: Onions release their flavor compounds after being cut. Storing them in the fridge can cause the flavors to dissipate and weaken, resulting in bland or less flavorful onions.

3. Cross-contamination: Cut onions can easily absorb odors and flavors from other foods in the refrigerator. They can also release their own pungent aroma, which can affect the taste of other stored items.

4. Moisture Absorption: Onions tend to absorb moisture from the refrigerator environment. This can cause them to become soft and lose their crispness.

To store cut onions properly:

- Wrap tightly: Wrap the cut onion tightly in plastic wrap or place it in an airtight container to minimize exposure to air and prevent cross-contamination.

- Keep in a cool, dry place: Store the wrapped onion in a cool, dry area of your kitchen, such as the pantry or a cupboard, to extend its shelf life.

- Use promptly: Cut onions are best used within 3-4 days for optimal flavor and quality.

Alternatively, you can store leftover onions in the freezer. Here's how:

- Blanch: Blanch the onion pieces by immersing them in boiling water for 2-3 minutes to retain their texture and flavor.

- Cool and drain: Drain the onion pieces and cool them quickly by immersing them in ice water. Pat dry thoroughly.

- Freeze: Place the blanched and dried onion pieces in freezer-safe bags or airtight containers, ensuring they are well-sealed.

Frozen onions can be kept for several months and can be used directly from frozen for cooking.