Ouzo has its roots in tsipouro, which is said to have been the pet project of a group of 14th century monks living in a monastery on Mount Athos. One version of it was flavored with anise. This version eventually came to be called ouzo.
Modern ouzo distillation largely took off in the beginning of the 19th century following Greek independence, with production centered on the island of Lesbos, which claims to be the originator of the drink and remains a major producer. When absinthe fell into disfavor in the early 20th century, ouzo was one of the products whose popularity rose to fill the gap; it was once called "a substitute for absinthe without the wormwood". In 1932, ouzo producers developed a method of distillation using copper stills that is now the standard method of production. One of the largest producers of ouzo today is Varvayiannis (Βαρβαγιάννης), located in the town of Plomari in the southeast portion of the island, while in the same town Pitsiladi (Πιτσιλαδή), a variety of high-quality ouzo, is also distilled.
Ouzo is traditionally served with a small plate of a variety of appetizers called mezes, usually small fresh fish, fries, olives and feta cheese. Ouzo can be described to have a similar taste to absinthe which is liquorice-like, but smoother.
On October 25, 2006, Greece won the right to label ouzo as an exclusively Greek product. The European Union now recognizes ouzo, as well as the Greek drinks tsipouro and tsikoudia, as products with a Protected Designation of Origin, which prohibits European makers other than Greece and Cyprus from using the name.
The origin of the name "ouzo" is disputed. A popular derivation is from the Italian "uso Massalia" - for use in Marseille - stamped on selected silkworm cocoons exported from Tyrnavos in the 19th century. According to anecdote, this designation came to stand for "superior quality", which the spirit distilled as ouzo was thought to possess.
During a visit to Thessaly in 1896, the late professor Alexander Philadelpheus delivered to us valuable information on the origins of the word "ouzo", which has come to replace the word "tsipouro". According to the professor, tsipouro gradually became ouzo after the following event: Thessaly exported fine cocoons to Marseilles during the 19th century, and in order to distinguish the product, outgoing crates would be stamped with the words "uso Massalia"—Italian for "to be used in Marseille". One day, the Ottoman Greek consulate physician, named Anastas (Anastasios) Bey, happened to be visiting the town of Tyrnavos and was asked to sample the local tsipouro. Upon tasting the drink, the physician immediately exclaimed: "This is uso Massalia, my friends"—referring to its high quality. The term subsequently spread by word of mouth, until tsipouro gradually became known as ouzo.—The Times of Thessaly, 1959.
Ouzo production begins with distillation in copper stills of 96 percent alcohol by volume (ABV) ethyl alcohol of agricultural origin. Anise is added to the alcohol, and sometimes other flavorings such as star anise, coriander, cloves, and cinnamon are also added. The flavoring ingredients are often closely guarded company secrets, and distinguish one ouzo from another. The result is a flavored alcoholic solution known as flavored ethyl alcohol, or more commonly as ouzo yeast—μαγιά ούζου in Greek—the term for "yeast" being used by Greeks metaphorically to denote that it serves as the starting point for ouzo production.
Makers of high-quality "100% from distillation" ouzo (such as Varvayiannis, Babatzim (ouzo classic) and Pitsiladis) proceed at this stage with water dilution, bringing the ouzo to its final ABV. But most producers combine the "ouzo yeast" with less expensive ethyl alcohol flavored with 0.05 percent natural anethole, before water dilution. Greek law dictates that in this case the ouzo yeast cannot be less than 20 percent of the final product.
Sugar may be added before water dilution, which is done mostly with ouzo from Southern Greece.
The final ABV is usually between 40 and 50 percent; the minimum allowed is 37.5 percent.
Aperitif drink 
In modern Greece, ouzeries (the suffix -erie is imported from French) can be found in nearly all cities, towns, and villages. These cafe-like establishments serve ouzo with mezedes — appetizers such as octopus, salad, sardines, calamari, fried zucchini, and clams, among others. It is traditionally slowly sipped (usually mixed with water or ice) together with mezedes shared with others over a period of several hours in the early evening.
In other countries it is tradition to have ouzo in authentic Greek restaurants as an aperitif, served in a shot glass and deeply chilled before the meal is started. No water or ice is added but the drink is served very cold, enough to make some crystals form in the drink as it is served.
Ouzo is often referred to as a particularly strong drink, although its alcohol content is not especially high compared to other liquor. The reason mainly has to do with its sugar content. Sugar delays ethanol absorption in the stomach, and may thus mislead the drinker into thinking that they can drink more as they do not feel tipsy early on. Then the cumulative effect of ethanol appears and the drinker becomes inebriated rather quickly. This is why it is generally considered poor form to drink ouzo "dry hammer" ("ξεροσφύρι", xerosfýri, an idiomatic expression that means "drinking alcohol without eating anything") in Greece. The presence of food, especially fats or oils, in the upper digestive system prolongs the absorption of ethanol and ameliorates alcohol intoxication.
Ouzo is a clear liquid. However, when water or ice is added, ouzo turns a milky-white colour. This is because anethole, the essential oil of anise, is soluble in alcohol but not in water. Diluting the spirit causes it to separate creating an emulsion, whose fine droplets scatter the light. This process is called louching, and is also found while preparing absinthe.
Drinks with a similar flavor 
Similar aperitifs include oghi (from Armenia and among Western Armenians), Rakı from Turkey, pastis (France), and arak (from the Levant). Its aniseed flavor is also similar to the anise-flavored liqueurs of sambuca (Italy) and anís (Spain) and the stronger spirits of absinthe (Switzerland). It is a variation of мастика, mastika from Bulgaria and the Republic of Macedonia. It can be consumed neat or mixed with water. Aguardiente (Colombia), made from sugar cane, is also similar.
See also 
- Epikouria Magazine, Spring/Summer 2007
- Encyclopædia Britannica: Micropaedia article on "ouzo".
- "Greeks toast EU's ruling on ouzo". Theage.com.au. 2006-10-25. Retrieved 2011-10-14.
- Oxford English Dictionary online, Oxford University Press, retrieved September 7, 2007
- G. Babiniotis, Λεξικό της Νέας Ελληνικής Γλώσσας (2002), p. 1285
- G. Clauson, An Etymological Dictionary of Pre-Thirteenth Century Turkish, Oxford 1972, p. 288
- Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης, Λεξικό της Κοινής Νεοελληνικής, 1998, s.v. ούζο
- Epikouria Magazine Spring/Summer 2007
- "The production method (of ouzo)" (in Greek). Tsou.gr. Retrieved 25 December 2011.