Freeze-drying fruit at home?

Question

Is it possible to freeze-dry fruit at home without expensive special equipment (or get the same dryness otherwise)? Especially I want to get the fruit to the crisp dryness¹ of freeze-dried fruit compared to the still slightly damp / soggy dryness of hot-air dried fruit.

[Edit] Well, turns out, basically no. Freeze-drying not only involves the ability to freeze the food to low temperatures (which can be achieved), but also creating a low pressure environment and controlled heating of the the food in that environment (Not easily achievable or controllable at home). More info from Wikipedia

_{1. It should feel absolutely dry to the touch, and crumble / break when handled roughly rather than stretch / bend.}

Answer 1

Assuming you have a frost-free freezer (which dehumidifies the cold air), I'd experiment by laying sliced fruit on a sheet (maybe on a layer of waxed paper) and putting it in the freezer. Pull out a slice every day or two to check its crispness. The time necessary will depend on the type of fruit, its moisture content, the slice thickness, and the room's humidity.

Answer 2

The frost-free freezer that kajaco suggested is definitely worth a try is you have access to one.

An easy hack to get a similar result is to use dry ice. As far as i know, this works for things that have a low amount of water to start with and do not know how apples will behave as they have a lot of water. For this, you need some dry ice, put 2-3 cm of it at the bottom of a cardboard container that has soles on the sides and place the fruit slices on top of it in a single sheet (no stacking)

You may also try to first dry the apples first in the oven in order to get most of the moisture out. You may find a decent guide for that here.

Do remember that in order to get the desired humidity (crumble / break when handled roughly rather) you will need to protect them from any moisture after the drying as well as during the storage. I am almost sure that a simple zip-lock bag will not do the trick and that the air inside the bag / jar may be too moist already at the time of sealing and so it may alter your desired result.

Answer 3

Most modern freezers are the frost free type. You would know if yours isn't one because you would have to defrost it once a month or so. Ever forget about a bag of frozen veggies for a couple months? (I'm a bachelor, do it all the time) The veggies are shrivelled and there's a bunch of ice in the bag. If you leave anything in there long enough all the moisture will eventually be pulled out and turned to ice.