CAN OVERNIGHT LAST ALL DAY? (2024)

Generally, "overnight" is intended to mean eight to 10 hours, and in most cases even 12 probably wouldn't hurt. But a carefully written recipe should let us set our own schedules. Just tell us how many hours, thank you; we're old enough to choose our own bedtimes.

Is white chocolate caffeine-free?

Yes. It's also chocolate-free.

White chocolate is the fat from the cocoa bean, euphemistically known as cocoa butter, mixed with milk solids and sugar. It contains none of the chocolate liquor from those wonderful, though inauspiciously brown, cocoa-bean solids that give chocolate its unique character and rich flavor. If you choose a white-chocolate-topped dessert to avoid chocolate's caffeine, bear in mind that cocoa butter is a highly saturated fat. You can't win 'em all.

To cut down on my use of fat, I put some oil in a spray bottle, but all it did was shoot out a heavy, calorie-laden stream. Is there a better way to make my own "nonstick cooking spray"?

Yes, there is a better way.

Ordinary plastic spray bottles are made to spray watery liquids, not oily ones. Water is "thinner" (less viscous) than oil and breaks up easily into a mist, but the paltry pressure from a trigger pump isn't enough to break oil down into microscopic droplets, the way a pressurized aerosol can can.

Williams-Sonoma cookware stores and catalogue sell a sturdy little stainless-steel olive-oil sprayer called QuickMist. Other housewares stores carry the aluminum Misto brand. In either case, you put oil in it and pressurize it by pumping the cap. The oil then sprays out in a fine mist at the touch of a button, just as if from an aerosol can. It's great for low-calorie coating of frying pans, grill pans and salad greens-- everything you use those commercial cooking sprays for.

Incidentally, I also keep a small, trigger-operated plastic bottle of plain water in the kitchen for a variety of moisturizing chores. Overcooking and staleness are often just a matter of the food's drying out. Sometimes when a food is too dry, I give it a brief spritz of water. The best way to freshen up a loaf of crusty French bread, I've found, is to dampen it lightly with a spritz of water and put it in a 300-degree toaster oven for two minutes.

Why does vanilla extract smell so good and make food taste so good, yet taste so awful from the bottle?

Vanilla extract is around 35 percent ethyl alcohol, which has a harsh, biting flavor. Whiskeys and other distilled beverages contain even more alcohol, of course, but they are lovingly produced by time-honored flavoring and aging processes that soften the harshness.

Vanilla extract, in order to be labeled as such, must be extracted from real vanilla beans. But the chemical that gives the beans most of their great flavor and aroma is vanillin, and chemists can make vanillin a lot cheaper than the vanilla plant can. Synthetic vanillin is used commercially to flavor baked goods, candies, ice creams and such. It's chemically identical to the natural chemical, and is the main ingredient in imitation vanilla flavoring. But real vanilla extract is so much more complex than just plain vanillin that it doesn't pay to buy the imitation stuff, especially since you use so little of it and it keeps forever. Robert L. Wolke is professor emeritus of chemistry at the University of Pittsburgh. His latest book, "What Einstein Didn't Know--Scientific Answers to Everyday Questions," will be published in paperback by Dell in January. Send your food or cooking questions to the Food Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 or e-mail them to wolke+@pitt.edu. Individual responses cannot be made, but the most interesting questions will be addressed in this column.