Thanks to a trend sweeping the cocktail world, you can now walk into a liquor store and legally purchase a bottle of alcohol-Agwa de Bolivia-flavored with coca leaves. Suddenly exotic choices in flavors is enlivening what had been the sleepy category of liqueurs. With revived selection comes a transparency about formulas. While classics are often veiled in secret recipes known only to the monks who invented them, many prideful modernists call out their ingredients. The term liqueur can be hazy. Wine Spectator's Jack Bettridge explains.