FOR YEARS, MOST PEO ple have regarded “pizza” and “frozen pizza” as two distinct species of food. Americans love pizza, especially when you can make a phone call and have it delivered to your door still hot from the oven. Frozen pizza, by contrast, was long considered the dinner of last resort. Frozen pizza has been around for at least 50 years, but only in the last decade have manufacturers been able to make one that rivals the quality of fresh-baked.

Although pizzerias have existed in America since at least the 189Os, pizza was little known outside the Northeast until after World War II, when GIs returned from Italy with a taste for it. As home freezers became widespread in the postwar consumer boom, some pizzerias began offering unbaked frozen pies, but customers complained about soggy or crumbly dough and tasteless toppings. Bakers trying to make a decent frozen pizza faced two big problems: the formation of ice crystals and the interruption of biological and chemical processes.

The key to a good crust is leavening. Normally, before baking the pie, a pizza maker will “proof” the dough, letting it sit as the yeast digests sugars in the flour through the process of fermentation. By-products of fermentation include ethanol (one of the ingredients that make the aroma of fresh-baked bread so beguiling) and carbon dioxide. In dough made from wheatbased flours, filaments of a protein called gluten form a network that traps the carbon dioxide. This creates bubbles of gas that expand as the pizza is baked, causing the dough to rise.

The problem is that if you proof your dough and then freeze it, ice crystals will form and break down the dough’s gluten structure. In the early days of frozen pizza, the result was often a crumbly and less flavorful crust. Ice crystals also destroyed the cell structure of meat and vegetable toppings, so as the pizza thawed, the toppings released water. This seeped down to the crust, leaving it soggy and the toppings dry and flavorless.

Similar problems plagued many frozen foods in the industry’s early days, and they still afflict home cooks. The answer, as developed by Clarence Birdseye in the 1920s, is extremely rapid “flash freezing,” which occurs too fast for destructive ice crystals to form. Unfortunately, flash-freezing equipment was beyond the reach of most pizzerias. One low-cost technique that helped somewhat was partially baking the crust before adding the toppings and freezing the pizza. This drove off some of the water from the crust and firmed up the gluten structure.

The first nationally marketed brand of frozen pizza, debuting sometime in the 1950s, was Celentano Brothers, but the first big name in the business was Totino. In 1951 Rose and Jim Totino opened one of the first pizzerias in Minneapolis (it’s still there). Supposedly, Rose secured a $1,500 loan by baking one of her famous pizzas and serving it to a delighted banker. A decade later, with business booming, the Totinos decided to branch out into frozen pizza. They bought an abandoned factory but couldn’t raise enough money to convert it into a facility that could mass-produce flash-frozen pizza shells. They ended up buying frozen shells from a Chicago company. Rose complained that they tasted like cardboard, but buyers were eager nonetheless. By the late 1960s Totino’s was the top-selling frozen pizza in the United States.

In 1975 Pillsbury bought the company for $20 million, and Rose Totino, a high school dropout, became Pillsbury’s first female vice president. (Her husband was already in failing health and would die in 1981.) In 1979 she received a patent on a pizza crust designed especially for freezing. The crust was fried at the factory, making it more resistant to the ravages of freezing and thawing. At the opening of Pillsbury’s 1980 annual meeting, the deeply religious Rose Totino closed an invocation with “Oh, and Lord, I forgot to thank you for crisp crust.”

Not everyone was so thankful. Quality was still nowhere near equal to fresh-baked, so through the 1980s, frozen pizza occupied an increasingly tight niche. Sales growth averaged a sluggish one percent a year, even with innovations such as French-bread and microwaveable pizzas. Competition for shelf space in the frozen-food aisle was fierce. With chains like Domino’s offering to rush hot pizza to your doorstep in 30 minutes or less, about the only thing most frozen pizzas had going for them was, as one manufacturer put it, “an exceptional price-value relationship for households with kids.” In other words, they were cheap and children liked them. So did parents, especially since they didn’t have to eat them.

Kraft Foods, which made the popular if oddly named Tombstone Pizza, decided that substantial growth wouldn’t come by grabbing market share from rival frozen pizzas or other supermarket convenience foods but by grabbing it from “real pizza,” the takeout and delivery market. To do this, Kraft had to duplicate the total sensory experience of real pizza—not just taste, but appearance, scent, and “mouth feel” as well.

The company made a good start by joining forces with General Foods in 1989. General Foods owned several patents for yeast-leavened dough that could be frozen for extended periods, then thawed and baked successfully. This feat is achieved with such additives as gums, protein film formers, and surfactants, which enable the leavened dough to retain its structure during freezing and thawing. The resulting combination of puffiness and sturdiness makes possible the vaunted “rising crust” of modern frozen pizzas. Chemical leavening agents give a boost to the process, but the distinctive smell and taste, manufacturers insist, comes from the use of live yeast. High-speed “blast freezing” and vacuum-sealed packaging further preserve the flavor of both crust and toppings and increase the shelf life.

Kraft introduced its DiGiorno line of pizzas in 1995. Soon afterward, Schwans followed with its Freschetta brand, which uses a different process developed in Europe. Despite the premium price tag—around six dollars a pie, high for frozen food but lower than fresh-baked—DiGiorno and, to a lesser extent, Freschetta soon dominated the frozen-pizza market. Annual frozen-pizza sales had totaled less than $1 billion at the start of 1995. Two years later, sales topped $2 billion, with most of that growth coming from premium, rising-crust pizzas. Since then, annual sales have more than doubled, to upward of $5 billion.

That’s still small change compared with the $30 billion worth sold by parlors ranging from the corner pizzeria to chains like Little Caesars and Pizza Hut. But frozen-pizza makers are not done innovating. According to the latest figures, only 17 percent of frozen pizzas are baked in a microwave, mostly because it’s hard to get the yeast to react properly. Using a conventional oven works better but is almost as slow as having a pie delivered. But DiGiorno has just introduced its first microwaveable “rising crust” pizza, which cooks in just five minutes. With the frozen/fresh convenience gap growing and the quality gap shrinking—plus the option of designing your own custom-made pineapple-and-Beer Nuts pie—technology is transforming frozen pizza from a punch line into something approaching a delicacy.