Caramelizing Onions – (Or Is It)?
When I think of raw onion, I think of a punch of concentrated, peppery flavor. I think of watering eyes and harsh sulfur compounds. I think cold, crisp, crunchy and pungent. Caramelized onions are a whole other ballgame.
Caramelized onions are sweet and buttery, soft and kind of slippery. They are mellow and full of deep, rich, sweet flavor—slightly nutty and the perfect accompaniment to a steak or a goat cheese pizza. What kitchen alchemy is it that can turn a pungent raw onion into a sweet and melting treat?
Obviously, caramelized onions are brown. In cooking, browning takes place in several ways. One way is through caramelization, the process by which sugars react with sugars in the presence of high heat.
Another way is through the Maillard reactions. Named for the chemist who first studied these reactions in 1912, the Maillard reactions, of which there are many, are a series of browning reactions that occur when certain sugars react with the amino acids found in proteins. These reactions are accelerated by heat and also the pH of the food being cooked.
Needless to say, a scientific explanation of these reactions is pretty exhaustive and exhausting. As cooks, what we need to understand is that a brown color and a more complex flavor are generally the end result of these reactions. We can use caramelization and the Maillard reactions to produce beautifully browned, deeply flavored foods, even if we do not understand the precise chemistry by which it all occurs.
While onions are made up mostly of carbohydrates in the form of fiber and sugar, they do contain a small amount of protein. Knowing this tells us that browning will occur through both caramelization (sugars reacting with sugars) and Maillard reactions (sugars reacting with amino acids)