A cooking apple or culinary apple is an apple that is used primarily for cooking, as opposed to a dessert apple, which is eaten raw. Cooking apples are generally larger, and can be tarter than dessert varieties. Some varieties have a firm flesh that does not break down much when cooked. Culinary varieties with a high acid content produce froth when cooked, which is desirable for some recipes. Britain grows a large range of apples specifically for cooking. Worldwide, dual-purpose varieties (for both cooking and eating raw) are more widely grown. John Claudius Loudon wrote in 1842: