The freezer in your kitchen likely gets down to temperatures around -20° C (-4° F). “That keeps your ice cream cold, but it doesn’t turn your ice cream into an impenetrable block of ice,” says Paula Cannon, an associate professor of molecular microbiology and immunology at the University of Southern California’s Keck School of Medicine.
Pfizer’s promising COVID-19 vaccine, by contrast, must be stored at about -70° C (-94° F)—a temperature cold enough to harden ice cream into a spoon-breaking block of ice, and that only specialized freezers can produce.
