How Do Yellow Onions, Red Onions, and Other Varieties Differ?

Onions are the third most consumed fresh vegetable in the United States, following only potatoes and tomatoes. The average American enjoys around 18.3 pounds of onions annually. It's no wonder—onions are a versatile kitchen essential. From caramelizing and frying to pickling, they add flavor to many savory dishes. While often used as an aromatic or supporting ingredient, onions can shine as the main event in soups, dips, and pastas. However, slicing them isn't for the faint of heart, as they can make you tear up. With so many varieties to choose from, it's easy to get confused at the grocery store. But don’t worry—when stored in a cool, dry, dark place, onions have a long shelf life. In most supermarkets, you'll find onions in large bins separated by type, such as red and yellow onions. Look for firm, heavy onions with dry, papery skins. The freshest ones are free of bruises, discoloration, or sprouts.

Types of Onions

The allium family includes hundreds of onion varieties, but most grocery stores offer four main types: yellow, white, red, and sweet. Here’s when and why to pick one over the others.

Yellow Onions

Yellow onions are best for cooking due to their naturally strong flavor, which is the result of their high sulfur content. This makes them more pungent compared to other onion types, which can be too intense and spicy to enjoy raw. However, cooking yellow onions softens their bite and brings out a milder, sweeter taste. They're ideal for dishes that require caramelized onions and work wonderfully in soups, stews, dips, sauces, and meat roasts.

White Onions

White onions are perfect for recipes that require raw onions, as they are milder and sweeter than yellow onions. They’re often used as a topping for sandwiches, burgers, hot dogs, and pizzas, and they’re a key ingredient in Mexican dishes like salsa, guacamole, fajitas, and tacos. While white onions are typically not the first choice for cooking, you can substitute them for yellow onions in a pinch.

Red Onions

Though their skin appears purple or magenta, these onions are known as red onions. They're perfect for grilling, roasting, and pickling. With a mild, subtly sweet taste, they can be enjoyed both raw and cooked, although some may find them a bit intense. To tame the heat, try slicing them thinly or soaking them in cold water. Due to their high sugar content, red onions are excellent for pickling, as the process enhances their natural sweetness while adding a tangy kick to dishes like salads, burgers, and sandwiches. They also make a great grilling option, as they hold their texture well and caramelize nicely over high heat.

Sweet Onions

Sweet onions have a yellow skin but shouldn’t be confused with yellow onions. They're distinguishable by their larger size and lighter skin. True to their name, sweet onions have a high sugar content, making them milder and less pungent than other varieties. They’re perfect for recipes that highlight their sweetness, such as tarts, jams, glazes, relishes, and onion rings.

A word of caution: Caramelizing sweet onions can enhance their sweetness to the point where they might overpower savory dishes, so it’s better to use a different type of onion for caramelizing.