In San Francisco, California, the Mexican-American burrito has become a city specialty, as the New York-based writer Calvin Trillin describes in his essay "Grandfather Knows Best": "In San Francisco, the burrito has been refined and embellished in much the same way that pizza has been refined and embellished in Chicago." Since its likely beginnings in the 1960s, the style has spread widely through the San Francisco Bay Area, and variations on it have spread throughout the United States.This type of burrito was born in the city's Mission District, and it is often called a Mission or Mission-style burrito as a result. Taquerias in the Mission, contrary to their taco-derived name, specialize in large, aluminum-foil wrapped burritos. The aluminum foil holds a large flour tortilla which is wrapped and folded around a variety of ingredients. The San Francisco burrito is distinguished partly by the amount of rice and other side dishes included in the package and partly by sheer size. A food critic working for the San Francisco Chronicle counted hundreds of taquerias in the San Francisco Bay Area, and noted that the question of which taqueria makes the best burrito can "encourage fierce loyalty and ferocious debate".