How To Tell If An Onion Is Bad

Onions are undoubtedly a staple for most home cooks and the foundation of many popular recipes. Their versatility—from soups to salads—makes them a kitchen staple and a great food item to buy in bulk. But if you’re questioning just how long that bag of onions has been in the pantry, it’s important to know how to tell if an onion is bad.

World master chef Fred Tiess tells Southern Living that you can use three different senses to tell if an onion has gone bad: sight, touch, and smell.

“An onion is bad if you see visible mold developing on the outer skin, if it is soft to the touch, or begins to smell musty,” Tiess says.

How To Tell If An Onion Is Bad

Tiess says that onions going bad happens more rapidly in recent years.

“You may have noticed in the past couple of years that the bag of onions that you purchased begins to go bad within a couple of days of purchase,” he tells Southern Living. “The reason is most likely that those onions were stored in refrigeration somewhere in the supply chain.”

According to the National Onion Association, onions should be able to be stored between 30 and 60 days if they are stored at room temperature in a dry and well-ventilated space. 

“The issue is when onions are stored under refrigeration moisture condenses on the outside of the onion which causes mold to develop,” Tiess says. 

What Is The Best Way To Store Onions So They Do Not Go Bad?

To make sure that your onions are less likely to turn bad, first select onions from grocers that have stored the onions properly. If the onions are cold to the touch, then chances are that they were stored in the refrigerator.

“Chat with your grocer to see which onions have been properly stored,” Tiess says. “If the onions have been stored properly, then place them in a well-ventilated dark space at room temperature.”

If the only onions that you can find are cold, Tiess recommends following these steps:

1. Wash the onion to remove any potential mold in a solution of three cups of water and one cup of white vinegar. 
2. Peel the onions and rinse again. 
3. Store the onions under refrigeration in a sealed container for three to five days. 

Can You Freeze Onions?

A pile of onions on their way to spoiling may have you wondering if it’s safe to freeze onions and the answer is: yes, if you plan on cooking them in a future recipe.

Tiess says to first make sure the onions are thoroughly washed, peeled, and cut into their desired shape.

“Store them in the freezer in smaller freezer bags, typically most recipes call for 1/2 to 1 cup of diced onions, so freezing them in those pre-portioned units can help during meal prep,” Tiess says.