Thursday, November 8, 2012

Onions… To Weep Or Not To Weep


I did a little research to find out about how to prevent crying when cutting onions. My personal experience has shown that it depends on the variety of onion.  Some seem stronger than others.  That being said, sometimes I don’t get a choice of what onions to use, I have to take what I can get and what I can afford. 

Onions are from a family called Alliums. This includes garlic, cloves, leeks and about 400 other plants.  To varying degrees, all of them have Amino acid sulfoxides form sulfenic acids. When you cut into an onion, you tend to crush the little cells containing these elements.  They produce propanethiol S-oxide. This gas reacts with the water in your tears to form sulfuric acid. The sulfuric acid burns, stimulating your eyes to release more tears to wash the irritant away.  Now you know! 

The National Onion Association says to reduce the tearing you can try several things:

First, chill the onions for 30 minutes
Leave the Root Attached

Then, cut off the top and peel the outer layers leaving the root end intact. (The root end has the highest concentration of sulphuric compounds that make your eyes tear.)

Linda’s Note:  You must use a very sharp knife.  A dull knife tends to crush those little acid cells


Most chefs I’ve seen will cut the onion in half, slicing through the root end like the picture above. I found that slicing this way makes short work of onions.

Peel back the skin, but leave it on the onion at the root base.

Thin Slices

When you are prepping onions for dehydrating, don’t bother to dice them.  Make the thinnest slices you can.  After they are dry, these will crush easily for whatever diced use you may need. 

When slicing your onions, be sure not to cut that last little bit holding the root.  The less damage to it, the less tearing.


Rack them and dehydrate at 115º.  Usually, they are dry overnight. 
  • Remember, the thicker the slices, the longer it will take for them to dry.
  • Onions should be crispy, not leathery.
  • Sweet onions like Vidalia will tend to be leathery because of the high sugar contend.


  1. Do you make onion powder for recipes with your dehydrated onions? Sorry to be bombarding you with questions, but I so want to learn! :-)

    1. Lisa, I am absolutely delighted that you are asking questions. please don't stop... it's what makes my day!

      Yes, dehydrated onions make excellent powder for cooking. You can also simply crush them in your hands and they make a great salad sprinkle.

      My recommendation is that you do not powder them until you are ready to use them. The flavor will last longer. If I know I will be using a good bit of powdered onions, I might make up a few weeks or maybe a month's supply of them ahead of time, but no more.

      You might want to look over my posts on herbs and spices.

      "Grinding Dehydrated Herbs & Spices"

  2. Hi Linda, love your blog, so much helpful info on dehydrating. Was wondering, when you dry onions do you set your dehydrator outside? I've seen so many blog posts about how bad the fumes are. I have a store bought dehydrator with 7 trays. So it can't pack much, but I don't want run everyone outside because I didn't think first. Thanks, dee

    1. Thank you for writing, and I appreciate how much you are helped.

      As to the onions, personally, I don't have a good place outside to put my machines. In Wyoming we have high winds that can rip the jacket off your back! I keep my machines inside, even if I'm drying onions or garlic!

      Mike isn't thrilled, but personally, I happen to like the wonderful kitchen smell of onions ... and even garlic. They stimulate wonderful feelings of cooking, homebody, and food attached to love and affection.

      Outside or inside? Personal preference. It's your home and your machine. Do what you please. :)

      Thanks for writing!