M Alice: How do freeze-dryers work? Why can’t you buy them for home use? I find practically no information on the subject, as if there was a coverup conspired by giant food-processing corporations. Am I just being paranoid? — Gnat, PB
Oh, yeah, probably. But you can be a paranoid with your own freeze-dryer if you have at least 10, 15, 30 thou hidden under your mattress. The technology ain’t cheap. Depending on whether you’re working on human tissue samples or carrots or bacteria or wet books or roses or your recently departed Pekingese, you stick the thing into the machine, wait hours or days for the temperature to reach, oh, maybe -20, -50, -90 degrees F, whatever the recipe calls for. Then you turn on the big sucking vacuum system to vaporize the ice crystals and whisk them into collectors so they won’t redeposit. Then you wait days, maybe weeks while the temperature is very carefully brought back up to normal. Of course, humidity immediately begins decomposing the stuff unless you seal it or further treat it.
If all this seems too much to handle after battling corporate conspirators all day, here’s a freebie from pre-Columbian Peru. The Incas invented a clever dry-freezing method for storing potatoes, which turn to mush if they fill with ice crystals. According to one food history book, they’d stomp around on the spuds until all the water was squished out, then put the mashed pulp outside to freeze. Is it cheaper to move to Machu Picchu or buy a freeze-dryer? The choice is yours.