This section is from the book "The American Woman's Cook Book", by Ruth Berolzheimer. Also available from Amazon: The Domestic Arts Edition of the American Woman's Cook Book.
Sugars - Granulated, confectioners', brown and maple sugar, corn sirup, molasses, honey and maple and cane sirups are all used in candy, according to the flavor and texture desired. The light-brown sugar should be chosen rather than the darker brown, for a candy of delicate flavor. The same thing is true if corn sirup or molasses is used; the lighter color gives the less strong flavor.
Brown sugar and molasses contain an acid, which if used in candies with milk causes the milk to curdle. Therefore, candy containing these two ingredients should be stirred while it is cooking. Crystallization does not readily occur here because the milk tends to prevent it.
Butter is often used because of its flavor and because it tends to make a creamy product. Other mild-flavored fats maybe used instead of butter, particularly in candies containing chocolate, brown sugar or molasses.
Chocolate contributes flavor and tends to make a smooth candy because of the fat it contains. Three tablespoons of cocoa and two-thirds of a tablespoon of butter may be used instead of one square of chocolate.