True or false? Aunt Jean’s rum cake won’t get you drunk. All the alcohol cooks away in the oven.

Answer: False. The room won’t spin after you eat one piece of cake, but there is still some alcohol in it. Alcohol has a lower boiling point than water, which is why people think it disappears in sauces and baked goods. But when you simmer a sauce containing wine or liquor, up to 50 percent of the alcohol can remain, says Robert Wolke, professor emeritus of chemistry at the University of Pittsburgh and the author of What Einstein Told His Cook (www.amazon.com, $26). The percentage depends on how long it simmers and other factors, like the size of the pan. When you’re baking a cake, the evaporated alcohol has to work its way out of the batter, so even less will “burn off” than in an open pan. Wolke also points out that rum is added for moisture as well as flavor. If it evaporated completely, you’d be left with a cake that wouldn’t be as moist as it should.