More than half of the sugar produced in the U.S. comes from sugar beets, misshapen, whitish-brown roots that resemble short, fat carrots.
Sugar beets grow in temperate climates, such as in Minnesota, North Dakota, and Idaho in the U.S., and in much of Europe, whereas sugar cane is a tropical plant, grown in the U.S. mainly in Louisiana and Florida.
Beet sugar refineries have the more difficult task because the beets contain many bad-tasting and foul-smelling impurities that must be removed. The impurities survive in the molasses, which is inedible and fit only for animal feed. For that reason there’s no such thing as edible brown beet sugar.
Once refined, cane sugar and beet sugar are chemically identical: they’re both pure sucrose and therefore should be indistinguishable from each other. Refineries don’t have to label their sugar as cane or beet, so you may be using beet sugar without knowing it.
If it doesn’t say “Pure Cane Sugar” on the package, it’s probably beet.
Nevertheless, some people who have long experience in making jams and marmalades insist that cane and beet sugars don’t behave the same.
Alan Davidson, in his encyclopedic Oxford Companion to Food (Oxford University Press, 1999), says that this fact “should cause the chemists to reflect, humbly, that they are not omniscient in these matters.” Touché.