The oldest sugar candies are presumed to have been made where the sugar cane plant was domesticated. Sugar cane probably originated in Papua New Guinea, and from there was taken to Southeast Asia and other Pacific Islands, and ultimately to India and China. From India, sugar spread to the Arab states and eventually to Europe.
Chemically, sugar candies are broadly divided into two groups: crystalline candies and amorphous candies. Crystalline candies are not as hard as crystals of the mineral variety, but derive their name and their texture from their microscopically organized sugar structure, formed through a process of crystallization, which makes them easy to bite or cut into. Fudge, creams, and fondant are examples of crystalline candies. Amorphous candies have a disorganized crystalline structure. They usually have higher sugar concentrations, and the texture may be chewy, hard, or brittle. Hard candies, such as lollipops, caramels, nut brittles and toffees are all examples of amorphous candies, even though some of them are as hard as rocks and resemble crystals in their overall appearance.
Crystalline candies are chemically described as having two phases, because the tiny, solid sugar crystals are suspended in a thick liquid solution. These are also called grained candies, because they can have a grainy texture. Amorphous candies are have only one phase, which is either solid or liquid, and do not have a grainy texture, so they may be called ungrained.
Commercially, candies are often divided into three groups, according to the amount of sugar they contain:
- 100% sugar (or nearly so), such as hard candies or creams
- 95% sugar or more, with up to 5% other ingredients, such as marshmallows or nougats, and
- 75 to 95% sugar, with 5 to 25% other ingredients, such as fudge or caramels.
Each of these three groups contains both crystalline (grained) and amorphous (ungrained) candies.
- Hard candies and pulled candies
- Hard candies (also called boiled sweets) are single-phase, amorphous sugar candies that are commonly made from a combination of sucrose and glucose syrups. They are typically about 98% or more solid sugar. They have a glassy, translucent appearance. Pulled candy, like rock or Brach's starlight mints, is a hard candy that has been pulled or stretched to incorporate air. This process makes the candy opaque.
- Fondant candy is a partly crystallized, two-phased sugar candy. It is about 88% sugar by weight, usually with much more sucrose than glucose. In making fondant, a stiff sugar paste is cooked to a high temperature, then carefully cooled and mechanically beaten to produce the desired texture.
- Caramels and toffees
- Caramels contain milk and are cooked to a lower temperature than most sugar candies; toffees are similar, but use less milk and are cooked hotter. In both cases, the milk protein causes these emulsified candies to hold their shapes and prevents the sugars from crystallizing. Their brown color is due to a Maillard reaction between the milk protein and the sugars.
- Fudges, which are made in a wide variety of flavors, are essentially two-phased, crystallized caramels, with a short texture (easily broken). Sugar crystals are formed either due to agitation or the addition of crystal seeds in the form of powdered sugar or crushed fondant candy. The texture depends on the number and size of sugar crystals, the fat content, and the dispersion of milk solids.
- Nougats and marshmallows
- Nougats and marshmallows are confectionery foams, full of air. In the final product, there is often as much air, or even more, than sugar; for marshmallows, a ratio of 5 parts air to two parts syrup by volume is typical. Chemically, they may be single-phase or two-phased. Marshmallows are stabilized by a colloid like gelatin. Compared to nougats, marshmallows have higher moisture content, are softer and more rubbery, and dry out more easily.
- Jellies and gums
- Jellies and gums are thick liquid sugar candies. Gums, such as wine gums, are drier than jellies. They are made from sugar syrup plus a gelling agent. They are cooked to the lowest temperature of all sugar candies and consequently have the highest water content of sugar candies, about 20 to 25% water. Their stiffness depends on the type and amount of gelling agent, the final concentration, the pH of the product, and other factors. The most popular forms of gelling agent are gelatin, agar-agar, starch (more typical of American jelly candies), and pectin (more typical of European candies). These produce different effects. For example, starch produces cloudy jellies, while high-methoxyl pectin produces clear ones. Agar-based jellies are harder to dissolve, and gelatin-based jellies have a more rubbery texture.
- Nut pastes
- The most common nut paste candy is marzipan, which is an almond nut paste. Nut pastes are made by mixing crushed nuts with a sugar syrup.
- Panned candies
- Panned candy is a category of candy that includes dragées and comfits. These candies are formed by coating nuts, preserved fruits, or other candies with either sugar or chocolate in a revolving pan.
- Pralines, truffles, and noisettes
- There is significant variation among pralines, truffles, and noisettes. In general, they involve roasting nuts in a high-temperature sugar syrup, and then grinding the cooled result into a paste.
- Lozenge pastes and cream pastes
- Lozenge paste is a sugar candy made by combining fine sugar with a natural gum like gum arabic. The paste is stamped, cut, and dried until almost no water content remains. Conversation hearts are an example of lozenge paste candies that have been manufactured for over a century. A cream paste may include gelatin and is not dried as completely.
- Licorice is a sugar candy flavored by liquorice plants. It is usually a stiff, gelatinous paste.
Historically, sugar candy was used for pharmaceutical preparations as well as food uses. The sugar candy was used to disguise the unpleasant taste of the drug ingredients. Cough sweets and some other drugs show this heritage in the form of sugar tablets containing drugs, active drug ingredients being added to hard candies, and panned sugar coatings surrounding unpalatable pills.
Storage and shelf life
Shelf life is largely determined by the amount of water present in the candy and the storage conditions. High-sugar candies, such as hard candies, can have a shelf life of many years if kept covered in a dry environment. Spoilage for low-moisture sugar candies tends to involve a loss of shape, color, texture and flavor, rather than the growth of dangerous microbes. Impermeable packaging can reduce spoilage due to storage conditions.
Sugar candies spoil more quickly if they have different amounts of water in different parts of the candy (for example, a candy that combines marshmallow and nougat), or if they are stored in in high-moisture environments. This process is due to the effects of water activity, which results in the transfer of unwanted water from a high-moisture environment into a low-moisture candy, rendering it rubbery, or the loss of desirable water from a high-moisture candy into a dry environment, rendering the candy dry and brittle.
- NPCS (2013). Confectionery Products Handbook (Chocolate, Toffees, Chewing Gum & Sugar Free Confectionery). India: Asia Pacific Business Press. pp. 9–13.
- Richardson, Tim H. (2002). Sweets: A History of Candy. Bloomsbury USA. pp. 68–69. ISBN 1-58234-229-6.
- McWilliams, Margaret (2007). Nutrition and Dietetics' 2007 Edition. Rex Bookstore, Inc. pp. 177–184. ISBN 978-971-23-4738-2.
- "Candy History: Sweethearts". NECCO. 2014.
- Edwards, W.P. (2000). The Science of Sugar Confectionery. Cambridge: Royal Society of Chemistry. p. 1. ISBN 9780854045938.
- Ergun R, Lietha R, Hartel RW (February 2010). "Moisture and shelf life in sugar confections". Crit Rev Food Sci Nutr 50 (2): 162–92. doi:10.1080/10408390802248833. PMID 20112158.