A Mission burrito (also known as a San Francisco burrito or a Mission-style burrito) is a type of burrito that first became popular during the 1960s in the Mission District of San Francisco, California. It is distinguished from other burritos by its large size and inclusion of rice and other ingredients. A key method to the burritos' construction is to steam the wheat flour tortilla to increase its flexibility prior to adding the other ingredients, although that is not a requirement and burritos may be grilled instead. It has been referred to as one of three major styles of burritos in the United States, following the earlier, simple burrito consisting of beans, rice, and meat. It precedes the California burrito, which was developed in the 1980s and contains cheese and potatoes.