Long before the high-heeled Sex and the City gals were sipping Cosmos with a citrus kick on TV, medieval merrymakers were drinking flavored vodka in Poland and Russia. But the spices and honey added to vodka centuries ago were used to mask impurities of the early distillation process and make it a palatable potable rather than enhance an otherwise pure white spirit that is a perfect match for fruit—and a balmy spring evening.   Vodka is a purer form of alcohol beverage than other distilled spirits, thanks to a carbon filtering process that removes impurities created by distillation.  Known for being clear, odorless, and flavorless, vodka’s natural affinity with fruit juices such as orange and grapefruit—which have been mixed in drinks for years—has helped spur the creation of citrus-infused spirits that satisfy the thirst for added flavor without added sweetness. (Why use canned grapefruit juice for that Greyhound when you can sip grapefruit flavored vodka instead?) Vodka distillers have perfected flavoring methods so you can easily enjoy the pure essence of fruit and the spirit from one bottle, and virtually all the popular brands offer citrus-flavored options. In fact, vodka is the United States’ best selling spirit, due in part to flavor-infused varieties, of which citrus is the most popular category.  Fragrant blossoms of Mandarin oranges, zesty lemon peels, and cool limes are just some of the fruits that lend their essences to create delicious distillations with a lively citrus flair.    Russia’s Stolichnaya boasts of having introduced flavored vodka to the United States in 1986 with its lemon flavor, Limonnaya. Now called Stoli Citros, this was followed by an orange flavor, Stoli Ohranj, and the brand now features seven flavors. Sweden’s Absolut launched Citron in 1988, which is predominantly lemon but also includes flavors from other citrus fruits—the recipe is a closely guarded secret.  And in 1999, the company introduced its orange flavor, Mandrin, which is flavored with essential oils of mandarin and other oranges. Lemons and limes that ripen in a sunny Spanish citrus grove infuse Belvedere’s new Cytrus flavor, and Moroccan mandarin oranges, mandarin blossoms and limes from southeastern Spain are distilled in its orange offering, Pomarancza.   Just as each chef has a different way of cooking—and secrets as well—vodka distillers employ a variety of techniques to flavor their spirit. Essential oils from the peel of the fruit rather than the pulp produce the truest essence of flavor. Some distillers add aromatic oils to the clear vodka by macerating, or steeping, the fruit in the vodka for several weeks then distilling again to purify. Others use blends of natural fruit essences and add them to vodka at the end of the production process, just prior to bottling. And more cost-effective brands may use a blend of synthetic essences that are mixed with the vodka.   The new breed of citrus vodkas adds kick to your favorite cocktails or inspiration for new drinks. If you want to try them straight, place the bottle in the refrigerator or freezer for a nice chill.  When frozen, they can take on a cloudy, somewhat milky appearance due to the essential oils from the citrus peels—a good assurance they’re flavored with the pure essence of natural citrus fruit.  There’s nothing like succulent mandarin oranges or the fresh zest of lemon to help you shake up the taste of exotic locales.