Why soup is so good

Why is soup so common in all the world's cultures? What is it about soup that makes it so appealing, regardless of what local ingredients there are?

I think it is because every culture in history has had a "lower" class that has had to make do with the cheapest, least sought after ingredients. Higher "quality" ingredients often have as much to do with texture as with flavor, and the richest people in any society get the pick of the tenderest cuts of meat, the finest spring vegetables, and the freshest fruit. In contrast, the "peasantry" lives on the tougher cuts of meat, the bones often included, root vegetables and leftover fruit that has either been dried or fermented.

But these "lower" cuts of meat and root vegetables are not devoid of flavor, in fact they often have much more owing to what makes them less desirable: their texture. Tougher foods are denser, and contain more flavor, more varied tissues, and often more nutrients. Compare, for instance, an onion and an asparagus. Which has the more flavor? Sure, if you had to eat one raw you would probably pick the asparagus. But ask your self which one you would give up for life if you had to!

But using tougher foods does not mean you have to give up texture for the extra flavor; nor does intensity of flavor mean you have to have less subtlety. What it does mean is that you have to treat it differently from the way you treat "finer" foods.

For instance, a tenderloin, the tenderest cut of meat in most animals, is one that must be cooked quickly lest it get tough. But this type of cooking does little for the flavor, as it has no time to develop or convert the flavors that already exist. Again, the finer cuts are more about texture. But a flank steak, being much tougher already, benefits from a low, slow, wet cooking process that both extracts flavor and reduces toughness. Soups and stews are perfect for this method, as is braising. What you end up with is something at least as tasty as the tenderloin, and nearly as tender. And certainly cheaper!

Let's take this one step further, and ask what can be done with bones and gristle. Certainly no one wants to chow down on a hunk of bone, unless one is of the canine persuasion. But there is a lot of flavor, and a ton of nutrients just begging to be let out. After all, a lot of nutrients went into making them! This is where soup stock comes in.

Bones, gristle and similar tissues contain, among other things, collagen. This is a protein used in connective tissues, and it has some very interesting properties. Firstly, it dissolves in hot liquid. Second, it coagulates when it cools down, provided it is concentrated enough. If this makes it sound like gelatin, then you are correct: collagen is one of the main ingredients in gelatin. The third property of collagen that is of interest in the kitchen is that is carries flavors that water cannot.

By extracting the collagen from bones and tough tissues, we can get a lot of flavor and nutrients that would otherwise be thrown away. This can be done with any meat product. In restaurants, veal bones are often used for their high collagen content, but beef and chicken are also very common. Fish and seafood stocks can be made from bones, gills, fins, and shells. Ham hocks are often used to make a ham stock.

Martin Yan, the famous Chinese Chef, said it most succinctly: when you have a good stock, you can make a good soup. If I can sum up in a word what makes soup so universal, it would be "extraction". The slow, patient process of getting the most out of your ingredients. And that's what cooking with love is all about.

Erik Christensen