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How Ice Cream Works | The U.S. ice cream industry sells about a million gallons of ice
cream each year, dispensing cones, gallons, pints, sundaes and other desserts through grocery stores and ice cream shops.
In fact, eight percent of all the milk produced in the U.S. ends up in a frozen dairy product. Although ice cream can be easy to make at home, it is actually a very complex substance. In this article, we'll learn how it's made, what goes into it, and who invented it. We'll also learn how to quickly make ice cream in your kitchen. |
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| Ice Cream or Frozen Dessert? | |
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Not just any frozen treat can be called ice cream. In fact, the U.S.
Department of Agriculture has specific rules that define what can and can't be labeled "ice cream." To bear the "Meets USDA
Ingredient Standard for Ice Cream" stamp, it has to contain at least 10 percent milk fat, and a minimum of six percent
non-fat milk solids. A gallon has to weigh at least 4.5 pounds. The range of milk fat (sometimes referred to as butter fat) used in ice cream can go from the minimum 10 percent to a maximum of about 16 percent. Most premium ice creams use 14 percent milk fat. Higher fat content leads to better, richer taste and a creamier texture. Ice cream makers don't go higher than 16 percent because it would be costly and very high in calories. An ice cream with this much milk fat would also taste so rich that people would probably eat it in smaller amounts, which would be bad news for people who sell ice cream for a living. Other frozen desserts, such as sorbets, low-fat ice cream, and frozen yogurt, are not technically ice cream at all. Frozen custard is ice cream that has at least 1.4 percent egg yolk solids, and "soft serve" can be any frozen milk-based dessert that has not gone through the hardening process -- more on that later. In terms of specific ingredients, the recipe for ice cream is simple. But in scientific terms, it's complicated stuff. Ice cream is a colloid, a type of emulsion. An emulsion is a combination of two substances that don't normally mix together. Instead, one of the substances is dispersed throughout the other. In ice cream, molecules of fat are suspended in a water-sugar-ice structure along with air bubbles. The presence of air means that ice cream is also technically a foam. In addition to milk fat, non-fat milk solids, sugar, and air, ice cream also contains stabilizers and emulsifiers. Stabilizers help hold the air bubble structure together and give the ice cream a better texture. Although gelatin was originally used as a stabilizer, xanthan gum, guar gum, and other compounds are used today. Emulsifiers keep the ice cream smooth and aid the distribution of the fat molecules throughout the colloid. Egg yolks were once used, but ice cream manufacturers now tend to use other chemical compounds. These stabilizers and emulsifiers make up a very small proportion (less than one percent) of the ice cream. |
| Ice Cream Industry | |
| In 1999, retail sales of ice cream in the U.S., the worldwide leader
in ice cream production, topped $4 billion. In 2002, more than $20 billion was spent on frozen desserts. The leading states
in ice cream consumption are California, Indiana, Pennsylvania, Texas and New York. Americans ate an average of 21.5 quarts
of ice cream per person in 2004.
With that much money to be made, the ice cream industry can be secretive and underhanded. Deborah Hanny, owner of Sweet Jenny's Ice Cream in Williamsville, NY, protects her recipes carefully. Her shop has been photographed by men in suits and she once caught someone in her upstairs office hurriedly trying to copy down her recipes. Ice cream making secrets are seldom passed down from generation to generation these days. So where do people in the ice cream industry learn their craft? At ice cream school. Pennsylvania State University offers a week-long "Ice Cream Short Course" intended for industry professionals. The course teaches the science and technology used to make ice cream. They also offer Ice Cream 101 for ice cream hobbyists who just want to learn more about their favorite frozen treat. The University of Guelph, Ontario's Dairy Science and Technology school, also has a long history of teaching ice cream science. Next, we'll learn who invented ice cream. | |
| Ice Cream History | |
| The earliest reports of people enjoying flavored ice desserts come from
the Romans and the Chinese. Marco Polo returned from his famous expedition with fruit-flavored ices, reporting that Asians
had been making them for thousands of years. These delicacies became popular in France in the 1500s, but only among royalty.
Over the next few centuries, the process of making them evolved from hauling mountain ice to salt/ice freezing methods.
Cream was introduced as an ingredient, and by the 1700s, people were enjoying a dessert that was very similar to today's
ice cream. The hand-cranked ice cream freezer was first developed by Nancy Johnson in 1846. Ice was readily available from large warehouses in that era, so ice cream became a treat that could be enjoyed by almost anyone, not just the rich. Ice cream making was revolutionized again in 1851, when Jacob Fussel started the first wholesale ice cream manufacturing operation in Baltimore, Maryland. Fussel's dairy business had excess cream and he couldn't figure out what to do with it. He tried using it to make ice cream, and before long his ice cream business outsold the rest of the dairy. The business slowly evolved for the next few decades. Manufacturing methods and ingredients improved, while refrigeration technology became cheaper and more efficient. By the 1920s, home refrigerators and freezers became more common, which gave the ice cream industry another boost. Sugar was rationed in the U.S. during World War I, but the ice cream industry convinced the government that ice cream was an "essential food." Ice cream factories were allotted sugar rations and production continued. Ice cream increased in popularity until the Depression years caused a drop in sales for virtually all non-essential goods. Sales increased in the years leading up to World War II before leveling off in the post-war years. The rise of the giant supermarket created demand for cheaper, mass-produced ice cream, but quality suffered. The 1960s saw a resurgence in "premium" ice cream, while the following decades saw the market fragment into low-fat varieties for the health-conscious, including frozen yogurt, fruit bars, ice milk, fat-free ice cream, and dozens of other varieties. However, ice cream still makes up about 60 percent of the market share among frozen desserts [ref]. While ice cream is enjoyed worldwide, it has become an American tradition. In the next section, we'll see how ice cream is made. |
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