As is true of many geek-cooks, I am a serious devotee of Alton Brown--the creator and host of the Food Network Program "Good Eats". This show is a great resource for people (like me), who don't feel truly comfortable with a process unless they completely understand it. Good Eats is nice for that, because in addition to telling you what to do, Alton Brown tells you why you're doing it.
Here's an example--suppose you want to make mayonnaise. Whereas the usual cooking show (or cookbook) would simply tell you to "add the milk to the eggs very slowly," Alton Brown will tell you 1)When you make mayonnaise, you are making an emulsion, 2)An emulsion is a fine mixture of fat molecules and water molecules 3)Because fat and water don't mix, emulsions are very sensitive, and thus require an *extremely* slow introduction of the fats to water 4)If you screw this up, the fats will start to glob together, and the emulsion will "break".
What's so great about the latter method of learning to cook? A couple of things--first of all, learning the science behind a particular recipe can often give you insight recipes that may initially seem unrelated. For instance, once you know that mayonnaise is an emulsion, you can apply your knowledge about making mayonnaise to other emulsions--like buttercream frosting (which is an emulsion of eggs and butter). If you learned to make mayonnaise from an ordinary recipe, then you wouldn't necessarily know about emulsions, and the relationship between mayonnaise and buttercream would remain obscure. Without knowing their relationship, getting from mayonnaise to buttercream would be no easier than getting from mayonnaise to meringues. Placing those two foods in the same category, makes buttercream a variation on mayonnaise (strange, I know) and makes getting from one to the other much easier.
Secondly, knowing the science behind food lets you know why you are doing what the recipe tells you, and more importantly, when you don't have to. This makes altering an existing recipe much much easier. It is much easier to make substitutions when you know the purpose of each ingredient, and what other ingredients serve that same purpose. For example, in some recipes, a liquid serves only to keep something wet (in which case, feel free to substitute buttermilk for vinegar if you think that would somehow be tasty) whereas in others it serves another purpose as well, such as making a food more acidic (in which case, you would have to confine your substitutions to other acidic liquids).
On a more philosophical level, knowing how your food works is important because without that knowledge, I don't think that you can really call yourself a cook. As with many things, I feel that knowing how things work gives you an ownership over them, in a way that merely following directions does not. I didn't feel like I really owned my bike until I learned how all of it's component parts worked, and I don't feel like I own a food until I know how it's component parts work. That level of ownership is really liberating, because it leaves you free to wander as you please, with a reasonable chance of getting where you're going in the end.
Next post--Adventures in Cooking!