Soup is a primarily liquid food, generally served warm (but may be cool or cold), that is made by combining ingredients such as meat and vegetables with stock, juice, water, or another liquid. Hot soups are additionally characterized by boiling solid ingredients in liquids in a pot until the flavors are extracted, forming a broth. Traditionally, soups are classified into two main groups: clear soups and thick soups. The established French classifications of clear soups are bouillon and consomme. Thick soups are classified depending upon the type of thickening agent used: purees are vegetable soups thickened with starch; bisques are made from pureed shellfish or vegetables thickened with cream; cream soups may be thickened with bechamel sauce; and veloutes are thickened with eggs, butter, and cream. Other ingredients commonly used to thicken soups and broths include rice, lentils, flour, and grains; many popular soups also include carrots and potatoes. Soups are similar to stews, and in some cases there may not be a clear distinction between the two; however, soups generally have more liquid than stews. Evidence of the existence of soup can be found as far back as about 6,000 BC. Boiling was not a common cooking technique until the invention of waterproof containers (which probably came in the form of clay vessels). Animal hides and watertight baskets of bark or reeds were used before this. To boil the water hot rocks were used. This method was also used to cook acorns and other plants. The word soup comes from French soupe ("soup", "broth"), which comes through Vulgar Latin suppa ("bread

soaked in broth") from a Germanic source, from which also comes the word "sop", a piece of bread used to soak up soup or a thick stew. The word restaurant (meaning "[something] restoring") was first used in France in the 16th century, to refer to a highly concentrated, inexpensive soup, sold by street vendors, that was advertised as an antidote to physical exhaustion. In 1765, a Parisian entrepreneur opened a shop specializing in such soups. This prompted the use of the modern word restaurant for the shops. In America, the first colonial cookbook was published by William Parks in Williamsburg, Virginia, in 1742, based on Eliza Smith's The Compleat Housewife; or Accomplished Gentlewoman's Companion and it included several recipes for soups and bisques. A 1772 cookbook, The Frugal Housewife, contained an entire chapter on the topic. English cooking dominated early colonial cooking; but as new immigrants arrived from other countries, other national soups gained popularity. In particular, German immigrants living in Pennsylvania were famous for their potato soups. In 1794, Jean Baptiste Gilbert Payplat dis Julien, a refugee from the French Revolution, opened an eating establishment in Boston called The Restorator, and became known as "The Prince of Soups". The first American cooking pamphlet dedicated to soup recipes was written in 1882 by Emma Ewing: Soups and Soup Making. Portable soup was devised in the 18th century by boiling seasoned meat until a thick, resinous syrup was left that could be dried and stored for months at a time. The Japanese miso is an example of a concentrated soup paste.