How to Blanch Onions

Updated April 17, 2017

Blanching vegetables is a process where you cook the vegetables in boiling water for a short period of time and immediately place them into cold water to stop the cooking process. Blanching vegetables such as onions allows for easier removal of the skin. You can also blanch vegetables to prepare them to be frozen, though onions may be frozen without blanching, according to University of Nebraska Extension. Freezing your vegetables after they have been blanched helps preserve the vegetables nutrients and life.

Wash the onions and remove the ends. Cut a "X" at the root end. Do not cut to deep. This cut helps with the removal of the skin.

Bring a pot of water to boil. The pot must be large enough to fit all your onions in. The water should be at a full rolling boil before you place your onions in.

Prepare a large bowl with ice and cold water. This shocks the onions and stop them cooking once they have been removed from the boiling water.

Place the onions carefully into the boiling water. Set the timer for four minutes.

Using pot holders, remove the pot from the heat and strain the onions. Using a slotted spoon place the onions immediately into the cold water. Once cooled completely, drain the onions from the cold water.


Smaller onions will take less time to blanch and cook. Large onions may need to be blanched for up to 7 minutes. Chopped onions or onion rings should stay in boiling water only 10 to 15 seconds.


Always be careful around hot water and heat. Be sure to protect yourself with potholders.

Things You'll Need

  • Pot
  • Strainer or colander
  • Kitchen timer
  • Large bowl
  • Ice
  • Slotted spoon
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About the Author

Stephanie Cai began professionally writing for clients in 2010 and freelance writing in 2008. She is currently a writer for various online publications and is knowledgeable in fields such as health and beauty, fashion, celebrities, films and video games. Cai graduated from Hunter College with a Bachelor of Arts in creative writing.