Freeze-Drying Your Own Backpacking Meals: How to Eat Your Favorite Town Food on the Trail

[Drew Smith]

Companion forum thread to: Freeze-Drying Your Own Backpacking Meals: How to Eat Your Favorite Town Food on the Trail

In this freeze-drying installment, we discuss the history of freeze-drying and experiment with using a freeze dryer to prepare our favorite take-out town meal into the backcountry.

[Kevin Garrison]

Quick couple of questions.  Does each tray hold one meal?  Do you vacuum seal after they are done or does the freeze dryer both freeze and vacuum seal.  It seems like 3 days for 4 meals is a lot.

[Drew Smith]

@Kevin Garrison – I’d say more like 2-3 meals per tray (roughly a quart volume), so 8-12 per run if fully loaded. A run typically takes 30-36 hr, so 1.5 days rather than 3. Yes the process is slow, but the hands-on time with the dryer is fairly minimal: check/replenish oil levels in the vacuum pump, close the drain, a couple of entries on the touch screen and then you walk away until it’s done. You’ll spend much more time prepping the food (even take-out).

The dryer does not do any food storage work. You can vacuum-seal, but I do that more for individual meals pre- trip. For longer-term storage I have been packing food in resealable mylar bags and tossing in a few oxygen-absorbing packets. I’ll address food storage at more length in a future installment as this is fairly crucial to maximizing the value of freeze-drying.

[Josh J]

i’ve done some looking around and it looks like you can freeze dry with dry ice at home. anyone try it? might have to give it a go! especially since buy dry ice is way cheaper than buying a machine for $$$$ for the few times a year I’ll be using it

[Roger Caffin]

The dry ice (frozen CO2) will certainly freeze anything, but you will also need a vacuum pump to extract the water. and dry the food.

The point of freeze-drying is to avoid the movement of water from inside the food to the surface. That lets FD stuff rehydrate fast and taste better. The process of turning frozen water into vapour without a ‘wet’ stage is called sublimation. That is the secret.

Ordinary ‘dried’ food develops a thin shell of dried protein at the surface, and this changes the taste and can make rehydrating very slow. The protein is carried to the surface by the movement of the interior water.

The dried protein layer is often eaten before it rehydrates properly. It passes through the stomach and ferments in the intestines as it rehydrates.

Cheers

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