Common onions are normally available in three colour varieties:
- Yellow or brown onions (called red in some European countries), are the all-purpose full-flavoured onions and are the onions of choice for everyday use. Yellow onions turn a rich, dark brown when caramelized and give French onion soup its sweet flavour. Yellow onions have a nice balance of astringency and sweet in their flavor, becoming sweeter the longer they cook. They are usually fist-sized with a fairly tough outer skin and meaty layers.
- Red onions (called purple in some European countries) is a good choice for fresh use when its colour livens up the dish. It is also used in grilling and char-broiling. With their deep purple outer skin and reddish flesh, these are really the odd-guys out in the onion family. They are fairly similar to yellow onions in flavor, though their layers are slightly less tender and meaty. Red onions are most often used in salads, salsas, and other raw preparations for their color and relatively mild flavor. The lovely red color becomes washed out during cooking. If you find their flavor to astringent for eating raw, try soaking them in water before serving.
- White onions are the traditional onions that are used in classic Mexican cuisine. They have a golden colour when cooked and a particularly sweet flavour when sautéed. These onions tend to have a sharper and more pungent flavor than yellow onions. They also tend to be more tender and have a thinner, more papery skin. They can be cooked just like yellow onions, but we also like them in minced and added to raw salsas and chutneys.