We used to drop little vials of cells into liquid nitrogen for exactly the reason Rosa's puddle gives away: slow ice grows big crystals that tear through the membrane, fast ice stays small and leaves the cell more or less intact. We cheated, mind — a bit of glycerol in the mix to keep the crystals small. He got there with a hole in the ice and a wind off Labrador, which is roughly a better lab than any I worked in.
Didn't know until this week that the whole frozen food business starts with a man standing on ice in Labrador watching fish come up through a hole and go stiff in the wind before anybody could blink. Forty below will do that. Months later…
Ada, that's the whole argument against refreezing in one go — once it's thawed, the cells are already slashed open, and the second freeze builds big lazy crystals in a bag of juice. You get mush peas and a puddle in the pan. Freeze it once, hard, and leave it.