Science Fair Project Encyclopedia
In its simplest form, ice cream (originally iced cream) is a frozen dessert made from dairy products (milk, cream, or custard) combined with flavourings and sweeteners. This mixture is super-cooled by stirring while reducing its temperature to prevent large ice crystals from forming. Traditionally, the temperature has been reduced by placing the ice cream mixture into a container that is immersed in a mixture of crushed ice and salt. The salt causes a change of state from frozen to liquid water, removing a large amount of heat from the ice cream in the process.
Although the term ice cream is sometimes used to mean frozen desserts and snacks in general, it is usually reserved for frozen desserts and snacks made with a high percentage of milk fat.
Typical definitions for frozen desserts and snacks:
- Ice cream: Any frozen dessert product with 10% or more milk fat.
- Ice milk: Less than 10% milk fat and lower sweetening content.
- Frozen custard: More than 10% milkfat and egg yolk. Considered a kind of ice cream because of the high fat content.
- Sherbet: 1-2% milk fat and more sweetener than ice cream.
- Sorbet: fruit puree and no milk products
- Pop: frozen fruit puree, fruit juice, or flavored sugar water on a stick or in a flexible plastic sleeve.
- Kulfi another ice cream variant, which is dairy based, and brought to Pakistan and India by the Mughals from Persia during the 1500s, later as the result of colonialism and immigration to the West.
Many countries, including the United States, regulate the use of these terms based on specific percent quantities of ingredients.
Ice creams come in a wide variety of flavours, often with additives such as chocolate flakes or chips, nuts, fruit, and small candies/sweets. Some of the most popular ice cream flavours in supermarkets are vanilla, chocolate, strawberry, and Neapolitan (a combination of the three).
While it was not yet ice cream, per se, some examples of early pre-planned, ice dishes include the Roman emperor Nero (A.D. 37-68) who is said to have ordered ice to be brought from the mountains and combined with fruit toppings, and King Tang (A.D. 618-97) of Shang, China who is said to have had a method of creating ice and milk concoctions. People living directly alongside snow and ice have probably always put sweet things like honey and fruit juice on frozen water for variety, as some still do to this day. Snow-cones, made from balls of crushed ice topped with sweet syrup served in a paper cone, are consumed in many parts of the world.
Even earlier, in 400 BC Persia, a special chilled pudding-like dish, made of Rosewater and vermicelli, working out as something like a cross between a sorbet and a rice pudding was served to the royalty during summers. The Persians had already mastered the technique of storing ice inside giant naturally cooled refrigerators known as yakh-chals. These storages kept ice brought in from the winter or from nearby mountains well into the summer. The storages worked by using tall windcatchers that kept the sub-level storage space at frigid temperatures. The ice was then mixed in with saffron, fruits, and various other flavors. The treat, widely made today in Iran, is called "faludeh", which is made from starch (wheat, probably), spun in a kind of sieve-like contraption which produces threads or drops of the batter, which are boiled in water. The mix is then frozen, and mixed with Rosewater and lemons, before serving. 1 2
Contemporary western-style ice cream, however was probably “discovered” in the 1600’s, and was introduced to the United States jointly by Ben Franklin (who brought the idea from France), George Washington (who bought the first ice cream maker in the US), and Thomas Jefferson (who enthusiastically served it at parties and included a recipe in his published cook book). This was followed in the mid 19th century by the invention of the Ice Cream Soda, then the Ice Cream Sundae later in the century to placate religious conservatives, and both the Ice Cream Cone and Banana split in the first years of the 20th century.
Before the development of modern refrigeration by German engineer Carl von Linde during the 1870s, ice cream was a luxury item reserved for very special occasions. Today, ice cream is enjoyed around the world on a daily basis thanks to commercial mass-production and the home freezer. Ice cream is often bought in large tubs from supermarkets/grocery stores, in smaller quantities from ice cream shops, convenience stores, and milk bars, and in individual serves from small carts or vans at public events and places. There are even some ice cream manufacturers who sell ice cream products door-to-door from travelling refrigerated vans.
Modern commercial ice cream is made from a mixture of:
- 10-16% milk fat
- 9-12% milk solids-not-fat: this component, also known as the serum solids, contains the proteins (caseins and whey proteins) and carbohydrates (lactose) found in milk
- 12-16% sweeteners: usually a combination of sucrose and/or glucose-based corn syrup sweeteners
- 0.2-0.5% stabilizers and emulsifiers e.g., agar or carrageenan extracted from seaweed
- 55%-64% water which comes from the milk or other ingredients
These ingredients make up the solid part of the ice cream, but only 50% of the final volume, the remainder being air incorporated during the whipping process. Generally, the cheaper the ice-cream, the cheaper the ingredients, and the more air is incorporated (since ice cream is sold by volume, it's economically advantageous for producers to reduce the density of the product). Artisan-produced ice creams, such as Berthillon's, often contain none to very little air.
There are several popular legends surrounding the discovery of ice cream. Marco Polo supposedly saw ice cream being made on his trip to China, bringing the recipe home to Italy with him on his return. From there, Catherine de Medici's Italian chefs are said to have carried the recipe to France when she went there in 1533 to marry the Duc d'Orléans. Charles I was supposedly so impressed by the "frozen snow" that he offered his own ice cream maker a lifetime pension in return for keeping the formula secret, so that ice cream could be a royal prerogative. There is, however, no historical evidence to support this legend, which first appeared during the 19th century and was probably created by imaginative ice cream vendors. Ice cream most likely did originate in China, but it is unknown how and when the idea made its way into the Western world.
The making of ice cream was originally an extremely laborious process. Ice was cut commercially from lakes and ponds during the winter and stored in large heaps in holes in the ground, insulated by straw. Ice cream was made by hand in a large bowl surrounded by packed ice. The hand-cranked churn was invented in 1846, making production simpler, and the world's first commercial ice cream factory opened in Baltimore, Maryland in 1851. A big factor in making the production easier, obviating the need for cutting and storing natural ice, was the development of modern refrigeration during the 1870s (see above). The continuous process freezer was perfected in 1926, allowing commercial mass-production of ice cream and the birth of the modern ice cream industry.
The most common method for producing ice-cream at home is to use an ice-cream machine, generally some electrical device that churns the ice cream while refrigerated inside a household freezer.
A less common method is by mixing liquid nitrogen into the preparation, with vigorous stirring. The preparation is spectacular, since it results in a column of white condensed vapor, reminiscent of movie depictions of witches' cauldrons. The result, due to the extreme rapid cooling of the mixture, is a very smooth ice cream containing only small ice crystals. For obvious reasons, such a method is generally only used by physicists or other scientists with easy access to liquid nitrogen, in particular by graduate students. Important warnings: It is important to note that boiling nitrogen will displace breathable oxygen in the air when boiled, and that the use of a large quantity of liquid nitrogen in an inadequately ventilated space poses a possible suffocation risk. As long as the liquid nitrogen has completely vaporized, the remaining nitrogen bubbles are perfectly harmless, since nitrogen is anyway the major component of air; however, the nitrogen used in laboratories may have been contaminated by other chemicals, possibly harmful. Furthermore, care has to be taken not to leave chunks of very cold ice inside the mix. Wikipedia does not advocate the use of this method of preparation; see Wikipedia:Disclaimers.
Soy, rice, and non-dairy ice cream
Soy ice cream and rice ice cream are ice cream made without dairy, using soy milk or rice milk instead. Brand names include Soy Delicious, Tofutti, and Rice Dream. There are a variety of flavors and novelties. A minority of non-dairy ice creams are nut butter based.
Ice cream around the world today
Ice cream today is a traditional dessert in Italy, where it is still mostly hand-made, even if one of the most known ice cream machine makers is the Italian Carpigiani.
Before the cone became popular for serving ice cream, street vendors would serve the ice cream in a small glass dish referred to as a 'penny lick' or wrapped in waxed paper and known as a hokey-pokey (possibly a corruption of the Italian "ecco un poco" - "here is a little"). The use of a cone for serving ice cream can be traced back to Mrs Marshall's Cookery Book published in 1888. Agnes Marshall was a celebrated cookery writer of her day and helped to popularise ice cream. She patented and manufactured an ice cream maker and was the first person to suggest using liquid gases to freeze ice cream after seeing a demonstration at the Royal Institution. The first ice cream cones were introduced at the Word's Fair in 1904.
Around the turn of the 20th century, the ice cream soda was probably the single most popular teen delicacy in America, so much so that religious conservatives considered it sinful and subversive, giving rise to actual legal prohibition of the stuff on holy days, which probably influenced the creation of the modern ice cream sundae.
The history of ice cream in the twentieth century is one of great change and increase in availability and popularity. Retail storefront outlets developed as chains of ice cream stores, such as Baskin Robbins.
The popularity of selling ice cream in cones increased greatly after Charles E. Menches of St. Louis, Missouri used them at the St. Louis World's fair in 1904. The story behind why ice creams were sold at the World's Fair is that the ice cream seller had ran out of small cups, and without them could not sell anymore ice cream. Next door to the ice cream booth was the waffle booth, the waffle maker offered to make cones out of stiff waffles, and the new product became extremely popular at the fair and was widely copied by other vendors.
Ice cream became extremely popular throughout the world in the second half of the twentieth century after cheap refrigeration became common, and wages became high enough to indulge in such luxury items. Soon there was an explosion of ice cream stores and of flavours and types.
One important development in the twentieth century was the introduction of soft ice cream . A chemical research team in Britain (of which a young Margaret Thatcher was a member) discovered a method of doubling the amount of air in ice cream. This allowed manufacturers to use less of the actual ingredients, saving money. The ice cream was also very popular amongst consumers who preferred the light flavour, and most major ice cream brands now use this manufacturing process.
Recently, globalisation has brought ice cream styles from around the world to various places. For example, Japanese mochi ice cream is now popular in California, even outside of Japanese restaurants and Little Tokyos.
In the United Kingdom, much of the lower-priced ice cream sold, including that from ice cream vans, has no milk or milk solids content at all. Instead, it is made with vegetable oil, usually hydrogenated palm kernel oil. However, ice cream sold as dairy ice cream must contain milk fat, and many companies make sure that dairy is prominently displayed on their packaging or businesses.
Over 90% of the United States enjoys the taste of ice cream. Also, a whopping 98% of people have at least tried it at one point or another.
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- The Complete Guide To Ice Cream
- Ice Cream History and "who really invented the ice cream cone?"
- Great free downloadable guide to how to make ice cream from Quamut.com
- Cooking with Chemistry, Liquid Nitrogen Ice Cream
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