Okay, this one sounds a little crazy, but hear me out. You can keep cut onions fresh by submerging them in a bowl of cold water. Just put the cut onion pieces (diced or sliced) into a container, cover them completely with water, and pop a lid on it.
Water creates a barrier against oxygen, which is the main enemy of freshness. It also leaches out some of that harsh sulfur taste, making your future cooking a little sweeter. It’s like giving your onions a refreshing bath instead of letting them dry out in the desert of your fridge. Change the water every day for maximum crispness.
Trick #3: The Glass Jar Lockdown (My Favorite)
Here’s a pro tip I picked up from a chef friend. Take a clean glass jar (like a mason jar) and pack your chopped onions inside. Don’t fill it to the brim—leave a little air at the top. Screw the lid on tightly, then immediately put it in the fridge.
Glass is non-porous and doesn’t hold onto smells like plastic does. Plus, the tight seal slows down the onion’s respiration rate. It’s like putting the onion into a flavor-preserving time capsule. Your onions stay crunchy and potent for up to a week—yes, a week!—if you start with a fresh onion.
Onion Storage Guide: Keep Them Fresh for Months
