Chocolate chips are small chunks of chocolate. They are often sold in a round, flat-bottomed teardrop shape. They are available in numerous sizes, from large to miniature, but are usually less than 1 cm in diameter. Another variety of chocolate chips is rectangular or square chocolate chunks.
They are also found in many other retail food products such as granola bars, ice cream, and trail mix.
Chocolate chips can also be melted and used in sauces and other recipes. The chips melt best at temperatures between 104 and 113 °F (40 and 45 °C). The melting process starts at around 32 °C (90 °F) when the cocoa butter in the chips starts to heat. The cooking temperature must never exceed 115 °F (for milk and white) or 48 °C (120 °F) (for dark) or the chocolate will burn. Although convenient, melted chocolate chips are not always recommended as a substitute for melted baking chocolate. Because most chocolate chips are designed to retain their shape when baking, they contain less cocoa butter than baking chocolate. This can make them more difficult to work with in melted form.
Chocolate chips are a required ingredient in chocolate chip cookies, which were invented in 1937 when Ruth Graves Wakefield of the Toll House Inn in the town of Whitman, Massachusetts added cut up chunks of a semi-sweet Nestlé chocolate bar to a cookie recipe. The cookies were a huge success, and Wakefield reached an agreement in 1939 with Nestlé to add her recipe to the chocolate bar's packaging in exchange for a lifetime supply of chocolate. Initially, Nestlé included a small chopping tool with the chocolate bars. In 1941 Nestlé and one or more of its competitors started selling the chocolate in chip (or "morsel") form.