If you are new to using onions, or simply want a refresher, we’re sharing everything you need to know to have a successful experience. We’ve compiled the most important things about onions that will improve your knowledge and skills so you can cook with onions all year long. Here, in this Onions 101, you will find helpful information on choosing your onion variety, how to cut an onion, the difference between sautéing and caramelizing, the nutrition benefits of onions, staying tear-free while chopping, and what size onion equals one cup chopped.
Onions 101 — What’s the difference between red, white, and yellow onions?
Of course, you can tell an onion by the color of its skin, but once inside 
each onion variety has its own texture, flavor, and best uses. Some onions have a bolder flavor while others have a higher water content which can influence their storage time.
Red onions are popular due to their vibrant color, both on their skin and inside over each layer. They have less water content than yellow onions along with a flavor that can range from sharp to pungent that sweetens as they are cooked. They are often used for making pickled onions, but they can be eaten raw, grilled, or roasted, too.
Yellow onions have a yellow to brown skin and a longer storage life than other onions. They are the common onion variety used, so if you’ve cooked with onions before, chances are it has been a yellow onion. They have a strong onion flavor, but a mild aftertaste. Yellow onions can be used for any type of cooking, but they are especially good for making caramelized onions.
White onions have a light, white skin that stands out compared to yellow and red onions. They are often used in Mexican cuisine. These onions have a full, robust flavor that is also a bit pungent, and their storage life is shorter than yellow onions. White onions can be used for eating raw, grilling, and sautéing. They are ideal for any preparation that is lightly cooked.
Another category of onions is the sweet onion. They are a yellow onion, but they have a higher water content, so their storage-life is much shorter. You might find these onions under their commercial names such as Vidalia, Texas 1015, Sweetie Sweets or Walla Walla. They are known for their slightly sweet flavor and mild after-taste. Try baking, grilling, sautéing, or caramelizing with sweet onions.
What kind of onion should I use for my recipe?
The time of year can influence which onion is best to use because it indicates whether you are using fresh onions during their growing season or storage onions that allow us to enjoy onions every month of the year. While types of onions are often interchangeable the variety of onion does tell you some information about what it is best used for. Our Pick the Right Onions video on the Nature’s Ninja Homepage will help you choose the best onion for your recipes. Our Onion Color and Flavor Usage Guide is a handy resource to keep near your kitchen and to review before your next grocery shopping trip. The guide details the best ways to use each type of onion during the different months of the year.
What’s the best way to select and store onions?
Choose onions that have no visible bruising as this can cause them to decay more quickly. The skin should be dry, but not look dehydrated. The onion should be heavy for its size without any scent. Your onions should be stored in a cool, dry, and well-ventilated area. One important tip is to avoid storing onions with potatoes. Produce that releases moisture can cause your onions to spoil more quickly. For more tips on how to store your onions, our Storage and Handling Guide will help. We also have some tips and resources our blog post How to Store an Onion.
Refrigeration is only needed when you are trying to extend the shelf-life of whole sweet onions due to their higher water content and once any onion variety has been peeled or cut. Cut onions should stay fresh for 7 to 10 days when stored in a sealed container in the refrigerator. Our How To Guide shares even more information on how to select and store onions.
Can you freeze onions?
Yes, you can freeze onions for up to six months. Freezing is a good way to be sure you always have onions on hand for cooking and it can help you preserve onions that risk spoiling before you use them. We think this article, How to Freeze Onions in a Few Easy Steps, from The Spruce Eats, highlights the best process for freezing your onions.
What kind of onions should I use raw?
Red onions, white onions, and sweet onions are the best choices when eating raw onions such as in a topping for tacos, sliced onions on a burger, or slivers in a salad. You can use yellow onions, too, but they are often best for raw use when fresh and mild, March through August.
Remember that by nature, due to the healthy compounds that make up onions, they can be a sharp-tasting root vegetable with a pungent aftertaste. You can reduce this taste by placing your chopped or sliced onions in a bowl of ice water. Cover the bowl and refrigerate it for at least 90 minutes, preferably overnight. If you don’t have that kind of time, placing the onions in a colander and running cold water over them for at least 60 seconds will help.
What’s the best way to cut an onion?
When you bring your onion home it will still be in its skin, so we need to get it ready for slicing or chopping and then cooking. First, use a high-quality, sharp knife. Using a sharp knife is not only important for a clean cut; using a sharp knife also reduces damage to the cells of the onion which also reduces the potential for chopping it to make you tear up.
First, cut the top off the onion, but leave the root end intact. Peel and discard the outer skin. Cut the onion in half length-wise. Lay the halves cut-side down on your cutting board. For each cut, be sure to leave the root end intact as you work. It helps hold the onion together.
Make evenly spaced slices through the onion from root to the trimmed end. Hold the slices together and turn the knife so the sharp end of the blade is facing the onion and the knife is parallel to the cutting board. Make even horizontal cuts from trimmed end to the root end. Now, cut across the top of the onion to create a dice. Work from the trimmed end until you reach the root end.
Seeing a visual will help and we have one for you in our How to Cut an Onion Graphic. You can also watch our Cutting Onions video. These show you how to cut onions into slices and wedges, and how to prepare them for making onion rings.
Enlist the kids in the kitchen to learn with you
If you have kids in the kitchen with you, there are many ways they can help with onion prep. Younger children can peel the onion and transfer cut onions from the cutting board to cooking pans and bowls. Older children can stir the onions as they cook, and some may be able to help with the chopping. If you have preschoolers who are too young to be involved in food prep, check out our Nature’s Ninja Odyssey Printable Coloring Book. Children love it and they will learn about onions from seed to table while you prepare them.
How do I cut onions without crying?
Let’s begin with why onions make us cry. It’s the sulfur compounds in onions that react with enzymes that then create a compound that causes our eyes to water. The root end of the onion contains the highest concentration of these compounds which is one reason why keeping it intact while slicing your onions will help reduce crying. The best way to avoid tearing up when you cut onions, though, is to place the onions in the refrigerator and chill them for 30 minutes before you begin peeling and chopping them.
One medium onion chopped equates to one cup chopped onions ?
Onions are categorized by their diameter. A medium onion has about a 2 ½ – inch diameter and it will yield about 1 cup once chopped.
How do you sauté onions?
Sauteing onions is a cooking method that requires adding a fat, such as butter or olive oil, to a hot pan and then cooking the onions by tossing or stirring them in the pan. The process softens and sweetens onions, taming any pungent flavors and preparing onions for recipes such as Chunky Southwestern Soup and Creamy Onion Dip. Depending on the recipe, you can usually sauté onions from three to 15 minutes.
Always remember that high heat can cause onions to taste bitter. It’s best to use medium to low heat when sauteing your onions to prevent any off flavors from developing.
How do you caramelize onions?
Truly caramelized onions are medium-brown, tender, sweet, and nearly jam-like. The combination of a fat with long cooking times at lower temperatures gently browns, softens, and sweetens the onions. Plan to invest about 45 minutes in making caramelized onions and rest assured that it is worth it. Our Caramelized Onions 101 video is the best way to learn this cooking technique. We also have many caramelized onion recipes to try once you make them. You can start with this Caramelized Sweet Onion Hummus.
There are some tricks to reducing the time to caramelize onions and one of those is adding baking soda to the pan. We tested the process for Faster Caramelized Onions with some interesting results. We detailed each step of the process to help you decide if it’s worth saving the time. If you don’t need to save time, but you’d prefer a method that requires less hands-on work, you can caramelize onions in the slow cooker.
What are the health benefits of eating onions?
When it comes to healthy foods, onions really do have it all. They taste great and are one of the most widely
used vegetables in the home kitchen. They add an array of flavors to our meals while also being nutritious food. Onions provide nutrients with many health-promoting benefits that make them stand out among other healthy ingredients.
Onions are nutrient dense. This means that they provide a high concentration of vitamins, minerals, and beneficial compounds while being low in total calories. Onions are high in vitamin C, and a good source of dietary fiber and folic acid. Onions also provide vitamin B6, potassium, calcium, and iron. Additionally, they are low in sodium and contain no fat.
That only scratches the surface of the health benefits of eating onions. Onions are full of antioxidants which help protect the body from chronic disease such as heart disease. Specifically, onions contain quercetin, an anti-inflammatory compound that isn’t found in many foods. Onions are a main source along with apples, which also happen to be two ingredients that taste great when added to salads or stacked into sandwiches.
Onions are especially important for kid’s nutrition because they offer many key nutrients important for the development of healthy minds and bodies. You can find more details on the nutritional benefits of onions in our Onion Nutrition Information guide. If you’d like to dive deeper into the health benefits of onions that includes the findings of current research studies that support the onions role as a superfood you can read about Onion Health Research.
Whichever onion you choose and however you choose to prepare it, you have everything you need to know for getting started right here. We haven’t even touched on the many uses for onions beyond cooking and healthy eating. You can use onions to clean a well-used grill and you can use their skins to naturally dye Easter eggs! Check out our list of 15 Tips and Tricks for Using Onions that we’ve compiled so you can make the most of your onions!
