Do you know ...
... Why wine contains no more than 12 percent alcohol?
When grape juice is fermented, yeast converts the sugar in the grapes into alcohol and carbon dioxide. The yeast typically used for wine-making (Saccharomyces cerevisiae) will churn out alcohol until the level reaches 12 percent, at which point the yeast cells die of alcohol toxicity. (For comparison, humans die at a blood alcohol content of 0.3 percent to 0.6 percent.) No matter how sweet the grapes, it's the yeast's tolerance, not the amount of sugar that determines the alcohol content of wine.
... That aspartame and sugar have the same number of calories, gram for gram?
It's just that the artificial sweetener aspartame is 180 times sweeter than sugar. Diet soft drinks and sugar-free candy are virtually calorie-free because such a miniscule amount of aspartame is required to provide intense sweetness.
... Where sugar comes from?
Nearly all of the sugar in the United States comes from another root vegetable: the sugar beet. All plants store the sugar made from photosynthesis in their roots. Often plants store their energy as starch (think of a potato), but sugar beets are bred to store particularly high amounts of sucrose. The typical sugar beet consists of 18 percent sugar by weight, and yields about three teaspoons of the sweet stuff. Another source of sugar is sugar cane, a tropical grass with a sugary stalk. Sugar cane provides three-quarters of the world sugar supply, but the United States limits the amount of sugar cane that can be imported due to high domestic production of sugar beets.
... What the difference is between a yam and a sweet potato?
In most American markets, the orange-fleshed root vegetables labeled "yams" are actually just a more colorful variety of the whitish-fleshed sweet potato (Ipomoea batatas). True yams (Dioscorea sp.) are white, bland, starchy tubers that are used widely in tropical countries, but are rarely marketed in the United States. Unlike true yams, sweet potato "yams" are packed with beta-carotene, the orange pigment, which reduces risk of heart disease and cancer. Winter is sweet potato season; so enjoy your candied yams and sweet potato pie knowing that they are loaded with powerful antioxidants, and that they come from the same vegetable.
Whitson Herforth is a graduate student at the Friedman School. She has a BS in Plant Science from Cornell University.
