Ice cream (derived from earlier iced cream or cream ice) is a frozen dessert usually made from dairy products, such as milk and cream, and often combined with fruits or other ingredients and flavours. Most varieties contain sugar, although some are made with other sweeteners. In some cases, artificial flavourings and colourings are used in addition to, or instead of, the natural ingredients. The mixture of chosen ingredients is stirred slowly while cooling, in order to incorporate air and to prevent large ice crystals from forming. The result is a smoothly textured semi-solid foam that is malleable and can be scooped.
The meaning of the phrase "ice cream" varies from one country to another. Phrases such as "frozen custard", "frozen yogurt", "sorbet", "gelato" and others are used to distinguish different varieties and styles. In some countries, such as the United States, the phrase "ice cream" applies only to a specific variety, and most governments regulate the commercial use of the various terms according to the relative quantities of the main ingredients. In other countries, such as Italy and Argentina, one word is used for all variants. Analogues made from dairy alternatives, such as goat's or sheep's milk, or milk substitutes, are available for those who are lactose intolerant, allergic to dairy protein, or vegan. The most popular flavours of ice cream are vanilla and chocolate.
In the Persian Empire, people would pour grape-juice concentrate over snow, in a bowl, and eat this as a treat, especially when the weather was hot. Snow would either be saved in the cool-keeping underground chambers known as "yakhchal", or taken from snowfall that remained at the top of mountains by the summer capital — Hagmatana, Ecbatana or Hamedan of today. In 400 BC, the Persians went further and invented a special chilled food, made of rose water and vermicelli, which was served to royalty during summers. The ice was mixed with saffron, fruits, and various other flavours.