This afternoon my friend Scott dropped by for a visit. I was busy preparing a creamy spinach soup and soon we were engrossed in comfort food and stimulating conversation. Scott is a thinker on an illimitable quest for knowledge. He never ceases to be fascinated by the nature of things. Although cooking is by no means one of his passions, he queried me on such issues as the composition of evaporated milk, if microwave heating can cause cream based sauces to break, and why egg whites whip to a greater volume in copper bowls. All of this in turn, got me thinking.
The increased interest in food and cooking over the last couple decades has spawned a corollary fascination with food science. Some people not only want to know the hows, they want to know the whys. Humans are curious by nature and most of us need to know the underlying reason for phenomena. Why are older eggs better for hard-boiling? Why do severed apples, pears, and artichokes turn brown when exposed to air? Why can’t you cook acidic foods in aluminum pans? Why are custards cooked in a water bath?
In order to cook something properly you don’t have to know the why, if you’ve got the how down pat. For example, you may not know that when an alkaline substance and an acid are combined, the byproduct is carbon dioxide, a leavening agent. Yet ignorance of this fact will not prevent your biscuits from rising, assuming you added the proper amounts of buttermilk and baking soda to the batter. Some individuals don’t care about the why as long as the end result is successful.
But, (you know by now there’s always a but coming with me right?), knowledge of food science can make you a better cook. If you are simply mechanistically following a recipe you should be OK. But what if you are called upon to improvise, are supplied a shoddy recipe, or are forced to make something unfamiliar from scratch? Then my dear friends, you will need a deeper understanding of the products and processes at hand. Here are some examples how, or should I say, why?
Your friends are arriving soon for an afternoon of burgers, beers, and reposing in the sun. You decide to make your tried and true onion rings to accompany the burgers. But now you’re running behind schedule because your wife suddenly informs you that four unexpected guests are coming as well. So you prepare extra onion rings. The oil is ready and to save time you fry them all at once. But this time, instead of them turning out crunchy, they’re soggy and oily. What went wrong?
Fried foods cook, in part by steaming from the inside out. The intensely hot oil causes the internal moisture in the food to boil, which then escapes as steam. The outward rush of steam prevents the surrounding oil from permeating the food and making it greasy. This equilibrium creates that nirvana of a crunchy outside and a tender, non-oily inside. If the oil’s temperature is too low, insufficient steam is produced, the oil wins the shoving match, and your food tastes like a grease sponge.
Adding any amount of food to hot oil will drop the temperature of the oil. Adding a lot of food will lower it so much that it cannot recover quickly enough before steam will prevent it from infiltrating the food. Our inundated host should have cooked his onion rings in batches and poured his guests an extra beer in the meantime. 325 – 375 is the target temperature for most fried foods by the way. Procure a frying thermometer and eliminate the guesswork.
One day you decide to make homemade bread for the first time. One of the steps in the recipe says to dissolve the active dry yeast in warm water for 5 minutes. You do so, continue on with the recipe and in the end discover that your bread did not rise. What went wrong?
Simple. The recipe instructions were vague and deficient. Did you take the temperature of the water before adding the yeast? Of course not. The instructions didn’t tell you to.
Yeast is a living organism. It consumes sugars and expels carbon dioxide as a byproduct. This process, known as leavening, is what makes dough rise. Active dry yeast needs to be “proofed,” i.e., activated in warm water first. But the water must be between 100 and 110 degrees, preferably 105 to 110. Beyond 110 degrees it starts to die. Below 100 and it will not fully activate. Either way the leavening effect will be compromised and you’ll be making pitas instead of dinner rolls. Had you been fluent in Yeast 101 your knowledge would have transcended the pitfalls of the recipe. (PS. Make sure you check the expiration date on the yeast as well. Old yeast will not rise properly).
WORKING FROM SCRATCH
You just get home from food shopping. It’s your mom’s birthday and your parents will be arriving in two hours for dinner. You have a simple homey menu planned: a mixed green salad to start, followed by roasted chicken, mashed potatoes, and green beans. Nice. You make the salad and toss it in the fridge. Next you prep the chicken and get it in the oven. On to the potatoes. Yikes! You forgot to buy potatoes! No time to run back to the store. You frantically search your cupboards and discover a bag of rice. Rice pilaf! Of course! Your mom likes rice pilaf and you made it once before. You run through the steps in your head. Sauté some onion in butter and oil. Add the rice, cook for a few minutes and then add chicken broth, (luckily you have a couple of cans in the pantry). Bring to a boil and simmer for 15 minutes. Rest for five minutes, finish with herbs and seasonings, fluff with a fork. That’s precisely what you do but when it comes time to fluff the rice, you discover a sticky, glutinous mess. What went wrong?
Let me see the package of rice you used. Aha! Just as I suspected. You used Arborio rice, not long grain rice. So what you say? Well, not all rice is created equal. Short grain rices, such as Arborio, have a higher starch content than long grain rice. The lower starch content of long grain rice makes it ideal for a fluffy pilaf while that bag of Arborio is destined for risotto. The “creaminess” of a risotto is produced by the high degree of starch being released and incorporated into the fluid. This is why you constantly stir a risotto but not a pilaf. In this scenario, if you at least knew the properties of the two rices you could have evaded disaster. However, if you also knew how to make risotto, you would have turned forgetfulness into triumph.
If you’d like to learn more about food science I would recommend the classic text “On Food and Cooking” by Harold McGee. And remember; always wear your thinking cap under your chef’s hat.
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