Marlene Parrish - What Einstein Told His Cook 2

3.Transfer the mixture to the baking pan. Carefully place the pan in the oven. (It will want to slosh over.)

4.Bake uncovered for 45 minutes. With a fork or a wooden spoon, stir the polenta until evenly combined and smooth. Bake for 5 minutes longer, or until slightly puffy.

MAKES ABOUT 8 CUPS, OR 8 SERVINGS

VARIATIONS ON THE THEME

Polenta with Gorgonzola: Spoon soft, cooked polenta into a warmed serving dish. Make a well in the center and fill it with, say, 3 tablespoons unsalted butter and 3 ounces crumbled Gorgonzola cheese. Amounts will vary according to the amount of polenta you have made. Spoon some of the butter and cheese onto each serving of polenta.

Broiled Polenta Slices: Spoon soft, cooked polenta into a greased 9-inch square pan. Spread to make a layer about ½ inch thick. Chill. Turn the polenta out of the pan onto a work surface, and cut into squares or rectangles. Place the pieces on a greased cookie sheet. Brush with melted butter and broil, turning once, until browned and crisp on both sides.

Leftover Polenta: Spoon soft, cooked polenta into a greased loaf pan. Smooth the surface with a wooden spoon, cover with plastic wrap, and refrigerate. Cold polenta, sometimes called mush, is delicious for breakfast. Cut into slices, fry in butter or bacon fat, and top with maple syrup.

TORTILLA TIPS

My local market sells two types of Mexican tortillas: flour and corn. I assume that the flour tortillas are made out of regular wheat flour. But the corn tortillas are made out of masa harina, which, I’m told, is a kind of flour made from corn. Can you tell me how it’s made? And why is lime listed among the ingredients?

You’re correct about the flour tortillas, which should rightly be called wheat flour tortillas, because there are many other kinds of flour made from a wide variety of grains, including barley, rye, and rice. But you’ll rarely find flour tortillas south of the border. In Mexico tortillas are made from corn. Flour tortillas are a Tex-Mex invention.

The word flour evolved from flower , as used metaphorically to mean the best part of something, such as the flower of a plant or, in culinary use, the best part of a cereal grain. The supposedly inferior parts, the chaff and bran of the wheat berry and the hull of the corn kernel, have presumably been disposed of. To complicate matters, however, the literal translation of the Spanish masa harina is “flour dough,” with no specification of the kind of flour. On corn tortillas you may also see the more explicit harina de maíz , which distinguishes corn flour from harina de trigo , or wheat flour.

Spanish class dismissed.

The cellulose hulls of corn kernels can be loosened and the germs released by being soaked in water containing an alkali. Acids can be powerful chemicals, but so can alkalis. One exceedingly strong alkali is sodium hydroxide (NaOH), also known as caustic soda or lye. It’s so powerful that we use it to unclog drains—it actually dissolves hair and grease. (It turns the grease into soap, but that’s in Chemistry 102.)

In Mexico, the corn kernels are treated with lime, which is much milder than lye but still strong enough to open the cellulose husks of the corn kernels and uncover the starchy endosperm. Lime has been used for this purpose for thousands of years in Mexico and Central America. The husked kernels are then washed, dried, and ground or pounded into masa (dough).

Small balls of the dough are flattened into very thin, almost perfect disks by the astoundingly dexterous hands of Mexican women, then baked on a hot griddle for 30 to 60 seconds on each side, and distributed still warm and fresh to lucky local Mexicans, who have never had to deal with the factory-produced, machine-rolled-and-stamped-out, imitations that we gringos must often settle for. The main problem with these commercial pretenders is that a fresh corn tortilla should contain about 40 percent moisture, which is almost impossible to maintain during the packaging, freezing, and shipping of the mechanized version.

Sidebar Science: Lime in the limelight

LIMESTONE,seashells, coral, chalk, marble, eggshells, pearls, stalactites, and stalagmites all consist mainly of a remarkably versatile and plentiful chemical compound called calcium carbonate (CaCO 3). It constitutes about 7 percent of our planet’s crust, the 20-mile-or-so-thick top layer. When heated to 1520 to 1650°F (825 to 900°C), calcium carbonate decomposes into carbon dioxide gas (CO 2) and calcium oxide or lime (CaO). Lime has been used for centuries to make mortar, glass, and many other useful materials.

When lime is added to water, it forms calcium hydroxide, Ca(OH) 2, also known as limewater or slaked lime. It is quite alkaline, but not as much so as lye.

The Aztecs used an even more easily obtained alkaline material to treat their corn: wood ashes. All plant materials, including wood, contain potassium (it’s the “potash” in fertilizers), and when they are burned, their ashes are rich in the alkaline chemical potassium carbonate.

The Aztecs didn’t know all that, because Chemistry 101 wasn’t scheduled to be taught for another five hundred years. We can only guess at why they started boiling their corn in water containing wood ashes.

HELLO, SUGAR!

I’m amazed at how many prepared foods list sugar among their ingredients. Do the manufacturers think the only way to make something taste good is to make it sweet?

The fact that everybody likes sugar certainly has a lot to do with its presence in so many processed foods. Some breakfast cereals, for example, will surprise you with their content of sugar, if you figure it out. To check your cereals (or other manufactured foods) for sugar content, look at the Nurtrition Facts table and divide the number of grams of sugars per serving by the number of grams of cereal (or other manufactured food) per serving and multiply by 100. You’ll find, for example, that Kellogg’s Raisin Bran is 30 percent sugar by weight and Multi-Bran Chex is 21 percent sugar.

Note that the Nutrition Facts table lists “sugars,” in the plural. That means not only the sucrose from sugar cane (listed as “sugar” among the ingredients) but also sugars present naturally in the food, such as the lactose in milk, the fructose in fruit (such as the raisins in Raisin Bran), and the glucose, maltose, and fructose in any corn sweeteners that may be present. So in addition to sugar (sucrose), look for such ingredients as fructose, maltose, lactose, honey, corn syrup, high-fructose corn syrup, molasses, and fruit-juice concentrate. And note that “evaporated cane juice” is a sneaky euphemism used by “health-food” purveyors to avoid the dreaded s -word on their labels. Evaporated sugar-cane juice is, of course, nothing but sugar.

Then there are the sugar alcohols ( polyols ), which chemically speaking are not sugars, although they taste sweet. Glycerol (glycerin) is one. Their molecules have the characteristics of both sugars and alcohols. They contribute only about one-half to two-thirds as many calories as sugar, because they are converted only very slowly into glucose and may escape from the southern end of the alimentary canal before being fully metabolized. As a result, they can have a slight laxative effect if consumed in excessive quantities.

Because sugar alcohols don’t cause tooth decay or a sudden increase in blood sugar, they are used mainly in sugar-free candies and chewing gums. You’ll see them listed separately by name in the ingredient lists: sorbitol, xylitol, lactitol, mannitol, or maltitol. (Look for the suffix - itol .)