Ayran is a Middle Eastern yogurt drink which is especially popular in Turkey, although it is consumed in other regions of the Middle East and Mediterranean as well. In Turkey, this beverage is so popular that it is readily available in most fast food restaurants, and it is a common offering in the summer, when people view ayran as a refreshing drink in the heat. Some stores sell ayran pre-made, but it is also very easy to make.
The simplest form of ayran is made by blending equal parts of yogurt and water with salt to taste. The result is a thin drink which is often covered in a fine foam. Ayran is traditionally served cool, and it may be shaken or whisked right before it is served to ensure that it is frothy. People drink ayran alone, and also with meals, especially meals with spicy meats, where the yogurt helps to cool the mouth between bites.
Some variations on basic ayran are used by cooks in various regions of the Middle East. For example, cucumber water and various floral waters can be used in lieu of plain water, and ayran may be flavored with fresh mint, cracked pepper, or garlic, among other things. In Iran, it is sometimes carbonated. Savory versions of ayran pair especially well with meals, while sweeter versions may be drunk along as refreshments.
You may hear ayran called laban arbil, doogh, sheninah, moru, or tan, depending on where in the Middle East you are. In Turkey, ayran is naturally salty, which can come as a surprise to people who might be expecting a sweet yogurt drink. Some people have suggested that the salt flavoring references a time when yogurt was heavily preserved with salt to ensure that it would keep in the heat of the Middle East. Many traditional foods are very salty for reasons of preservation, so this theory is quite plausible.
The type of yogurt used has a profound impact on the flavor of ayran. Sheep's milk yogurt is more tangy, while goat's milk yogurt can be almost sharp and sometimes slightly acrid. Cow's milk yogurt is sweet and much creamier, and ayran can also be made with horse or camel's milk yogurts. The yogurt used is generally the traditional strained yogurt of the Middle East, so people making ayran with yogurt which has not been strained may need to use less water to get the consistency right.