Cookbook:Corn Syrup

| Sweeteners

Corn syrup is a glucose syrup made from corn, specifically cornstarch.

Characteristics
The syrup is made by heating the cornstarch with water, before adding an acid, enzymes, or both. These break down the starch into smaller molecules, ultimately producing a syrupy mixture of glucose, maltose, and other carbohydrates. This syrup may then be refined to remove any color and produce a clear, viscous syrup.

The characteristics of a given corn syrup will depend largely on how much of the starch is completely converted to glucose. A low-conversion syrup has a higher proportion of non-sugar carbohydrates, which makes it more viscous and less sweet, and the opposite is true for high-conversion syrups, which have more sugars compared to other carbohydrates. Generic corn syrup is somewhere in the middle, with medium conversion and about 50% glucose content. Some high-conversion corn syrups may be treated with another enzyme to convert a large amount of the glucose to fructose—this produces high-fructose corn syrup, which is sweeter than regular corn syrup. A syrup with 42% fructose and a roughly equal proportion of glucose is very common and has a similar sweetness to table sugar. Corn syrup may also have molasses or other colorants/flavorings added, which yields dark corn syrup.

Selection and storage
Corn syrup has a long shelf life. Keep it in a cool, dry place. It may darken very slightly over time.

Use
The primary applications of corn syrup include sweetening, moistening, coloring, and altering texture of various foods. Because the non-sugar carbohydrates of corn syrup interfere with its sugar molecules, low-to-medium conversion corn syrups are added to various confections (e.g. fondant, icing, caramel, etc) to reduce the risk of undesirable crystals. In a similar way, they also reduce ice crystal formation in ice creams, and they add body to foods. High-fructose corn syrup often provides a cheaper way to add sweetness to beverages compared to using table sugar. Dark corn syrup is sometimes used as a cheap substitute for molasses, but it has less flavor and different properties. Corn syrup also slows moisture loss from baked goods, which can maintain freshness.

Medium-conversion light corn syrup is a great all-purpose corn syrup to keep on hand for home bakers. Higher-skill bakers or those wanting to precisely optimize their recipes may want to experiment with different varieties of corn syrup

Substitution
Cane syrup, golden syrup, and light treacle are sometimes used as substitutes for corn syrup, but they are unfortunately not exact matches. They will produce different effects if substituted, so the best substitute for corn syrup is another glucose syrup, made from a different starch. Light corn syrup can be used instead of dark, though the flavor and color will be different. High-fructose corn syrup may be used in place of honey, which also has high fructose content —note, however, that the characteristic honey flavor will be lost.